diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index b5e66c17..e24afe1d 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -41,7 +41,8 @@ before_script:
 cache:
   key: "$CI_COMMIT_REF_SLUG"
   paths:
-    - /usr/lib/R/library/
+    - /usr/local/lib/R/
+    - /usr/lib/R/
 
 R 3:
   stage: build
diff --git a/NAMESPACE b/NAMESPACE
index b3c3d316..aee04dee 100755
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -76,6 +76,7 @@ export(g.test)
 export(geom_rsi)
 export(get_locale)
 export(ggplot_rsi)
+export(guess_ab)
 export(guess_atc)
 export(guess_mo)
 export(header)
diff --git a/NEWS.md b/NEWS.md
index 009cc4e7..b21e0fc8 100755
--- a/NEWS.md
+++ b/NEWS.md
@@ -7,6 +7,7 @@
   * Contains the complete manual of this package and all of its functions with an explanation of their parameters
   * Contains a comprehensive tutorial about how to conduct antimicrobial resistance analysis
 * Support for [`dplyr`](https://dplyr.tidyverse.org) version 0.8.0
+* Function `guess_ab` to find an antibiotic column in a table
 * Function `mo_failures()` to review values that could not be coerced to a valid MO code, using `as.mo()`. This latter function will now only show a maximum of 25 uncoerced values.
 * Function `mo_renamed()` to get a list of all returned values from `as.mo()` that have had taxonomic renaming
 * Function `age()` to calculate the (patients) age in years
diff --git a/R/eucast_rules.R b/R/eucast_rules.R
index 51926fea..616b8da9 100755
--- a/R/eucast_rules.R
+++ b/R/eucast_rules.R
@@ -30,7 +30,7 @@
 #' @param ... parameters that are passed on to \code{eucast_rules}
 #' @inheritParams first_isolate
 #' @section Antibiotics:
-#' To define antibiotics column names, input a text (case-insensitive) or use \code{NULL} to skip a column (e.g. \code{tica = NULL}). Non-existing columns will anyway be skipped with a warning.
+#' To define antibiotics column names, leave as it is to determine it automatically with \code{\link{guess_ab}} or input a text (case-insensitive) or use \code{NULL} to skip a column (e.g. \code{tica = NULL}). Non-existing columns will anyway be skipped with a warning.
 #'
 #' Abbrevations of the column containing antibiotics in the form: \strong{abbreviation}: generic name (\emph{ATC code})
 #'
@@ -158,69 +158,69 @@ eucast_rules <- function(tbl,
                          info = TRUE,
                          rules = c("breakpoints", "expert", "other", "all"),
                          verbose = FALSE,
-                         amcl = 'amcl',
-                         amik = 'amik',
-                         amox = 'amox',
-                         ampi = 'ampi',
-                         azit = 'azit',
-                         azlo = 'azlo',
-                         aztr = 'aztr',
-                         cefa = 'cefa',
-                         cfep = 'cfep',
-                         cfot = 'cfot',
-                         cfox = 'cfox',
-                         cfra = 'cfra',
-                         cfta = 'cfta',
-                         cftr = 'cftr',
-                         cfur = 'cfur',
-                         chlo = 'chlo',
-                         cipr = 'cipr',
-                         clar = 'clar',
-                         clin = 'clin',
-                         clox = 'clox',
-                         coli = 'coli',
-                         czol = 'czol',
-                         dapt = 'dapt',
-                         doxy = 'doxy',
-                         erta = 'erta',
-                         eryt = 'eryt',
-                         fosf = 'fosf',
-                         fusi = 'fusi',
-                         gent = 'gent',
-                         imip = 'imip',
-                         kana = 'kana',
-                         levo = 'levo',
-                         linc = 'linc',
-                         line = 'line',
-                         mero = 'mero',
-                         mezl = 'mezl',
-                         mino = 'mino',
-                         moxi = 'moxi',
-                         nali = 'nali',
-                         neom = 'neom',
-                         neti = 'neti',
-                         nitr = 'nitr',
-                         norf = 'norf',
-                         novo = 'novo',
-                         oflo = 'oflo',
-                         oxac = 'oxac',
-                         peni = 'peni',
-                         pipe = 'pipe',
-                         pita = 'pita',
-                         poly = 'poly',
-                         pris = 'pris',
-                         qida = 'qida',
-                         rifa = 'rifa',
-                         roxi = 'roxi',
-                         siso = 'siso',
-                         teic = 'teic',
-                         tetr = 'tetr',
-                         tica = 'tica',
-                         tige = 'tige',
-                         tobr = 'tobr',
-                         trim = 'trim',
-                         trsu = 'trsu',
-                         vanc = 'vanc') {
+                         amcl = guess_ab(),
+                         amik = guess_ab(),
+                         amox = guess_ab(),
+                         ampi = guess_ab(),
+                         azit = guess_ab(),
+                         azlo = guess_ab(),
+                         aztr = guess_ab(),
+                         cefa = guess_ab(),
+                         cfep = guess_ab(),
+                         cfot = guess_ab(),
+                         cfox = guess_ab(),
+                         cfra = guess_ab(),
+                         cfta = guess_ab(),
+                         cftr = guess_ab(),
+                         cfur = guess_ab(),
+                         chlo = guess_ab(),
+                         cipr = guess_ab(),
+                         clar = guess_ab(),
+                         clin = guess_ab(),
+                         clox = guess_ab(),
+                         coli = guess_ab(),
+                         czol = guess_ab(),
+                         dapt = guess_ab(),
+                         doxy = guess_ab(),
+                         erta = guess_ab(),
+                         eryt = guess_ab(),
+                         fosf = guess_ab(),
+                         fusi = guess_ab(),
+                         gent = guess_ab(),
+                         imip = guess_ab(),
+                         kana = guess_ab(),
+                         levo = guess_ab(),
+                         linc = guess_ab(),
+                         line = guess_ab(),
+                         mero = guess_ab(),
+                         mezl = guess_ab(),
+                         mino = guess_ab(),
+                         moxi = guess_ab(),
+                         nali = guess_ab(),
+                         neom = guess_ab(),
+                         neti = guess_ab(),
+                         nitr = guess_ab(),
+                         norf = guess_ab(),
+                         novo = guess_ab(),
+                         oflo = guess_ab(),
+                         oxac = guess_ab(),
+                         peni = guess_ab(),
+                         pipe = guess_ab(),
+                         pita = guess_ab(),
+                         poly = guess_ab(),
+                         pris = guess_ab(),
+                         qida = guess_ab(),
+                         rifa = guess_ab(),
+                         roxi = guess_ab(),
+                         siso = guess_ab(),
+                         teic = guess_ab(),
+                         tetr = guess_ab(),
+                         tica = guess_ab(),
+                         tige = guess_ab(),
+                         tobr = guess_ab(),
+                         trim = guess_ab(),
+                         trsu = guess_ab(),
+                         vanc = guess_ab()) {
 
   EUCAST_VERSION_BREAKPOINTS <- "8.1, 2018"
   EUCAST_VERSION_EXPERT_RULES <- "3.1, 2016"
@@ -268,12 +268,80 @@ eucast_rules <- function(tbl,
   }
 
   # check columns
+  if (identical(amcl, as.name("guess_ab"))) { amcl <- guess_ab(tbl, "amcl", verbose = verbose) }
+  if (identical(amik, as.name("guess_ab"))) { amik <- guess_ab(tbl, "amik", verbose = verbose) }
+  if (identical(amox, as.name("guess_ab"))) { amox <- guess_ab(tbl, "amox", verbose = verbose) }
+  if (identical(ampi, as.name("guess_ab"))) { ampi <- guess_ab(tbl, "ampi", verbose = verbose) }
+  if (identical(azit, as.name("guess_ab"))) { azit <- guess_ab(tbl, "azit", verbose = verbose) }
+  if (identical(azlo, as.name("guess_ab"))) { azlo <- guess_ab(tbl, "azlo", verbose = verbose) }
+  if (identical(aztr, as.name("guess_ab"))) { aztr <- guess_ab(tbl, "aztr", verbose = verbose) }
+  if (identical(cefa, as.name("guess_ab"))) { cefa <- guess_ab(tbl, "cefa", verbose = verbose) }
+  if (identical(cfep, as.name("guess_ab"))) { cfep <- guess_ab(tbl, "cfep", verbose = verbose) }
+  if (identical(cfot, as.name("guess_ab"))) { cfot <- guess_ab(tbl, "cfot", verbose = verbose) }
+  if (identical(cfox, as.name("guess_ab"))) { cfox <- guess_ab(tbl, "cfox", verbose = verbose) }
+  if (identical(cfra, as.name("guess_ab"))) { cfra <- guess_ab(tbl, "cfra", verbose = verbose) }
+  if (identical(cfta, as.name("guess_ab"))) { cfta <- guess_ab(tbl, "cfta", verbose = verbose) }
+  if (identical(cftr, as.name("guess_ab"))) { cftr <- guess_ab(tbl, "cftr", verbose = verbose) }
+  if (identical(cfur, as.name("guess_ab"))) { cfur <- guess_ab(tbl, "cfur", verbose = verbose) }
+  if (identical(chlo, as.name("guess_ab"))) { chlo <- guess_ab(tbl, "chlo", verbose = verbose) }
+  if (identical(cipr, as.name("guess_ab"))) { cipr <- guess_ab(tbl, "cipr", verbose = verbose) }
+  if (identical(clar, as.name("guess_ab"))) { clar <- guess_ab(tbl, "clar", verbose = verbose) }
+  if (identical(clin, as.name("guess_ab"))) { clin <- guess_ab(tbl, "clin", verbose = verbose) }
+  if (identical(clox, as.name("guess_ab"))) { clox <- guess_ab(tbl, "clox", verbose = verbose) }
+  if (identical(coli, as.name("guess_ab"))) { coli <- guess_ab(tbl, "coli", verbose = verbose) }
+  if (identical(czol, as.name("guess_ab"))) { czol <- guess_ab(tbl, "czol", verbose = verbose) }
+  if (identical(dapt, as.name("guess_ab"))) { dapt <- guess_ab(tbl, "dapt", verbose = verbose) }
+  if (identical(doxy, as.name("guess_ab"))) { doxy <- guess_ab(tbl, "doxy", verbose = verbose) }
+  if (identical(erta, as.name("guess_ab"))) { erta <- guess_ab(tbl, "erta", verbose = verbose) }
+  if (identical(eryt, as.name("guess_ab"))) { eryt <- guess_ab(tbl, "eryt", verbose = verbose) }
+  if (identical(fosf, as.name("guess_ab"))) { fosf <- guess_ab(tbl, "fosf", verbose = verbose) }
+  if (identical(fusi, as.name("guess_ab"))) { fusi <- guess_ab(tbl, "fusi", verbose = verbose) }
+  if (identical(gent, as.name("guess_ab"))) { gent <- guess_ab(tbl, "gent", verbose = verbose) }
+  if (identical(imip, as.name("guess_ab"))) { imip <- guess_ab(tbl, "imip", verbose = verbose) }
+  if (identical(kana, as.name("guess_ab"))) { kana <- guess_ab(tbl, "kana", verbose = verbose) }
+  if (identical(levo, as.name("guess_ab"))) { levo <- guess_ab(tbl, "levo", verbose = verbose) }
+  if (identical(linc, as.name("guess_ab"))) { linc <- guess_ab(tbl, "linc", verbose = verbose) }
+  if (identical(line, as.name("guess_ab"))) { line <- guess_ab(tbl, "line", verbose = verbose) }
+  if (identical(mero, as.name("guess_ab"))) { mero <- guess_ab(tbl, "mero", verbose = verbose) }
+  if (identical(mezl, as.name("guess_ab"))) { mezl <- guess_ab(tbl, "mezl", verbose = verbose) }
+  if (identical(mino, as.name("guess_ab"))) { mino <- guess_ab(tbl, "mino", verbose = verbose) }
+  if (identical(moxi, as.name("guess_ab"))) { moxi <- guess_ab(tbl, "moxi", verbose = verbose) }
+  if (identical(nali, as.name("guess_ab"))) { nali <- guess_ab(tbl, "nali", verbose = verbose) }
+  if (identical(neom, as.name("guess_ab"))) { neom <- guess_ab(tbl, "neom", verbose = verbose) }
+  if (identical(neti, as.name("guess_ab"))) { neti <- guess_ab(tbl, "neti", verbose = verbose) }
+  if (identical(nitr, as.name("guess_ab"))) { nitr <- guess_ab(tbl, "nitr", verbose = verbose) }
+  if (identical(norf, as.name("guess_ab"))) { norf <- guess_ab(tbl, "norf", verbose = verbose) }
+  if (identical(novo, as.name("guess_ab"))) { novo <- guess_ab(tbl, "novo", verbose = verbose) }
+  if (identical(oflo, as.name("guess_ab"))) { oflo <- guess_ab(tbl, "oflo", verbose = verbose) }
+  if (identical(oxac, as.name("guess_ab"))) { oxac <- guess_ab(tbl, "oxac", verbose = verbose) }
+  if (identical(peni, as.name("guess_ab"))) { peni <- guess_ab(tbl, "peni", verbose = verbose) }
+  if (identical(pipe, as.name("guess_ab"))) { pipe <- guess_ab(tbl, "pipe", verbose = verbose) }
+  if (identical(pita, as.name("guess_ab"))) { pita <- guess_ab(tbl, "pita", verbose = verbose) }
+  if (identical(poly, as.name("guess_ab"))) { poly <- guess_ab(tbl, "poly", verbose = verbose) }
+  if (identical(pris, as.name("guess_ab"))) { pris <- guess_ab(tbl, "pris", verbose = verbose) }
+  if (identical(qida, as.name("guess_ab"))) { qida <- guess_ab(tbl, "qida", verbose = verbose) }
+  if (identical(rifa, as.name("guess_ab"))) { rifa <- guess_ab(tbl, "rifa", verbose = verbose) }
+  if (identical(roxi, as.name("guess_ab"))) { roxi <- guess_ab(tbl, "roxi", verbose = verbose) }
+  if (identical(siso, as.name("guess_ab"))) { siso <- guess_ab(tbl, "siso", verbose = verbose) }
+  if (identical(teic, as.name("guess_ab"))) { teic <- guess_ab(tbl, "teic", verbose = verbose) }
+  if (identical(tetr, as.name("guess_ab"))) { tetr <- guess_ab(tbl, "tetr", verbose = verbose) }
+  if (identical(tica, as.name("guess_ab"))) { tica <- guess_ab(tbl, "tica", verbose = verbose) }
+  if (identical(tige, as.name("guess_ab"))) { tige <- guess_ab(tbl, "tige", verbose = verbose) }
+  if (identical(tobr, as.name("guess_ab"))) { tobr <- guess_ab(tbl, "tobr", verbose = verbose) }
+  if (identical(trim, as.name("guess_ab"))) { trim <- guess_ab(tbl, "trim", verbose = verbose) }
+  if (identical(trsu, as.name("guess_ab"))) { trsu <- guess_ab(tbl, "trsu", verbose = verbose) }
+  if (identical(vanc, as.name("guess_ab"))) { vanc <- guess_ab(tbl, "vanc", verbose = verbose) }
   col.list <- c(amcl, amik, amox, ampi, azit, azlo, aztr, cefa, cfra, cfep, cfot,
                 cfox, cfta, cftr, cfur, chlo, cipr, clar, clin, clox, coli,
                 czol, dapt, doxy, erta, eryt, fosf, fusi, gent, imip, kana,
                 levo, linc, line, mero, mezl, mino, moxi, nali, neom, neti, nitr,
                 novo, norf, oflo, oxac, peni, pipe, pita, poly, pris, qida, rifa,
                 roxi, siso, teic, tetr, tica, tige, tobr, trim, trsu, vanc)
+  if (length(col.list) < 63) {
+    warning('Some columns do not exist -- THIS MAY STRONGLY INFLUENCE THE OUTCOME.',
+            immediate. = TRUE,
+            call. = FALSE)
+  }
   col.list <- check_available_columns(tbl = tbl, col.list = col.list, info = info)
   amcl <- col.list[amcl]
   amik <- col.list[amik]
@@ -339,8 +407,8 @@ eucast_rules <- function(tbl,
   trsu <- col.list[trsu]
   vanc <- col.list[vanc]
 
-  amount_changed <- 0
-  amount_affected_rows <- integer(0)
+  number_changed <- 0
+  number_affected_rows <- integer(0)
   verbose_info <- data.frame(rule_type = character(0),
                              rule_set = character(0),
                              force_to = character(0),
@@ -352,7 +420,7 @@ eucast_rules <- function(tbl,
 
   # helper function for editing the table
   edit_rsi <- function(to, rule, rows, cols) {
-    cols <- unique(cols[!is.na(cols)])
+    cols <- unique(cols[!is.na(cols) & !is.null(cols)])
     if (length(rows) > 0 & length(cols) > 0) {
       before <- as.character(unlist(as.list(tbl_original[rows, cols])))
       tryCatch(
@@ -376,8 +444,8 @@ eucast_rules <- function(tbl,
           tbl[rows, cols] <<- to
       ))
       after <- as.character(unlist(as.list(tbl_original[rows, cols])))
-      amount_changed <<- amount_changed + sum(before != after, na.rm = TRUE)
-      amount_affected_rows <<- unique(c(amount_affected_rows, rows))
+      number_changed <<- number_changed + sum(before != after, na.rm = TRUE)
+      number_affected_rows <<- unique(c(number_affected_rows, rows))
       changed_results <<- changed_results + sum(before != after, na.rm = TRUE) # will be reset at start of every rule
 
       if (verbose == TRUE) {
@@ -399,7 +467,7 @@ eucast_rules <- function(tbl,
     }
   }
   na.rm <- function(col) {
-    if (is.na(col)) {
+    if (is.null(col)) {
       ""
     } else {
       col
@@ -420,7 +488,7 @@ eucast_rules <- function(tbl,
   }
 
   # since ampicillin ^= amoxicillin, get the first from the latter (not in original EUCAST table)
-  if (!is.na(ampi) & !is.na(amox)) {
+  if (!is.null(ampi) & !is.null(amox)) {
     if (verbose == TRUE) {
       cat(bgGreen("\n VERBOSE: transforming",
                   length(which(tbl[, amox] == "S" & !tbl[, ampi] %in% c("S", "I", "R"))),
@@ -435,7 +503,7 @@ eucast_rules <- function(tbl,
     tbl[which(tbl[, amox] == "S" & !tbl[, ampi] %in% c("S", "I", "R")), ampi] <- "S"
     tbl[which(tbl[, amox] == "I" & !tbl[, ampi] %in% c("S", "I", "R")), ampi] <- "I"
     tbl[which(tbl[, amox] == "R" & !tbl[, ampi] %in% c("S", "I", "R")), ampi] <- "R"
-  } else if (is.na(ampi) & !is.na(amox)) {
+  } else if (is.null(ampi) & !is.null(amox)) {
     # ampicillin column is missing, but amoxicillin is available
     message(blue(paste0("NOTE: Using column `", bold(amox), "` as input for ampicillin (J01CA01) since many EUCAST rules depend on it.")))
     ampi <- amox
@@ -471,21 +539,21 @@ eucast_rules <- function(tbl,
       cat(rule)
     }
 
-    if (!is.na(ampi)) {
+    if (!is.null(ampi)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$order == 'Enterobacteriales'
                             & tbl[, ampi] == 'S'),
                cols = amox)
     }
-    if (!is.na(ampi)) {
+    if (!is.null(ampi)) {
       edit_rsi(to = 'I',
                rule = c(rule_group, rule),
                rows = which(tbl$order == 'Enterobacteriales'
                             & tbl[, ampi] == 'I'),
                cols = amox)
     }
-    if (!is.na(ampi)) {
+    if (!is.null(ampi)) {
       edit_rsi(to = 'R',
                rule = c(rule_group, rule),
                rows = which(tbl$order == 'Enterobacteriales'
@@ -502,7 +570,7 @@ eucast_rules <- function(tbl,
       changed_results <- 0
       cat(rule)
     }
-    if (!is.na(peni) & !is.na(cfox)) {
+    if (!is.null(peni) & !is.null(cfox)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$genus == "Staphylococcus"
@@ -516,21 +584,21 @@ eucast_rules <- function(tbl,
                             & tbl[, cfox] == 'S'),
                cols = c(oxac, clox))
     }
-    if (!is.na(cfox)) {
+    if (!is.null(cfox)) {
       edit_rsi(to = 'R',
                rule = c(rule_group, rule),
                rows = which(tbl$genus == "Staphylococcus"
                             & tbl[, cfox] == 'R'),
                cols = all_betalactam)
     }
-    if (!is.na(ampi)) {
+    if (!is.null(ampi)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$fullname %like% "^Staphylococcus saprophyticus"
                             & tbl[, ampi] == 'S'),
                cols = c(amox, amcl, pipe, pita))
     }
-    if (!is.na(cfox)) {
+    if (!is.null(cfox)) {
       # inferred from cefoxitin
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
@@ -548,14 +616,14 @@ eucast_rules <- function(tbl,
                             & tbl[, cfox] == 'R'),
                cols = c(carbapenems, cephalosporins[cephalosporins != na.rm(cfta)]))
     }
-    if (!is.na(norf)) {
+    if (!is.null(norf)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$genus == "Staphylococcus"
                             & tbl[, norf] == 'S'),
                cols = c(cipr, levo, moxi, oflo))
     }
-    if (!is.na(eryt)) {
+    if (!is.null(eryt)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$genus == "Staphylococcus"
@@ -572,7 +640,7 @@ eucast_rules <- function(tbl,
                             & tbl[, eryt] == 'R'),
                cols = c(azit, clar, roxi))
     }
-    if (!is.na(tetr)) {
+    if (!is.null(tetr)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$genus == "Staphylococcus"
@@ -589,14 +657,14 @@ eucast_rules <- function(tbl,
       changed_results <- 0
       cat(rule)
     }
-    if (!is.na(ampi)) { # penicillin group
+    if (!is.null(ampi)) { # penicillin group
       edit_rsi(to = 'R',
                rule = c(rule_group, rule),
                rows = which(tbl$fullname %like% "^Enterococcus faecium"
                             & tbl[, ampi] == 'R'),
                cols = all_betalactam)
     }
-    if (!is.na(ampi)) {
+    if (!is.null(ampi)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$genus == "Enterococcus"
@@ -613,7 +681,7 @@ eucast_rules <- function(tbl,
                             & tbl[, ampi] == 'R'),
                cols = c(amox, amcl, pipe, pita))
     }
-    if (!is.na(norf)) {
+    if (!is.null(norf)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$genus == "Enterococcus"
@@ -640,7 +708,7 @@ eucast_rules <- function(tbl,
       changed_results <- 0
       cat(rule)
     }
-    if (!is.na(peni)) {
+    if (!is.null(peni)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$fullname %like% "^Streptococcus (pyogenes|agalactiae|dysgalactiae|group A|group B|group C|group G)"
@@ -657,14 +725,14 @@ eucast_rules <- function(tbl,
                             & tbl[, peni] == 'R'),
                cols = c(aminopenicillins, ureidopenicillins, cephalosporins, carbapenems, clox, amcl))
     }
-    if (!is.na(norf)) {
+    if (!is.null(norf)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$fullname %like% "^Streptococcus (pyogenes|agalactiae|dysgalactiae|group A|group B|group C|group G)"
                             & tbl[, norf] == 'S'),
                cols = c(levo, moxi))
     }
-    if (!is.na(eryt)) {
+    if (!is.null(eryt)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$fullname %like% "^Streptococcus (pyogenes|agalactiae|dysgalactiae|group A|group B|group C|group G)"
@@ -681,7 +749,7 @@ eucast_rules <- function(tbl,
                             & tbl[, eryt] == 'R'),
                cols = c(azit, clar, roxi))
     }
-    if (!is.na(tetr)) {
+    if (!is.null(tetr)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$fullname %like% "^Streptococcus (pyogenes|agalactiae|dysgalactiae|group A|group B|group C|group G)"
@@ -698,14 +766,14 @@ eucast_rules <- function(tbl,
       changed_results <- 0
       cat(rule)
     }
-    if (!is.na(peni)) {
+    if (!is.null(peni)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$fullname %like% "^Streptococcus pneumoniae"
                             & tbl[, peni] == 'S'),
                cols = c(ampi, amox, amcl, pipe, pita))
     }
-    if (!is.na(ampi)) {
+    if (!is.null(ampi)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$fullname %like% "^Streptococcus pneumoniae"
@@ -722,14 +790,14 @@ eucast_rules <- function(tbl,
                             & tbl[, ampi] == 'R'),
                cols = c(amox, amcl, pipe, pita))
     }
-    if (!is.na(norf)) {
+    if (!is.null(norf)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$fullname %like% "^Streptococcus pneumoniae"
                             & tbl[, norf] == 'S'),
                cols = c(levo, moxi))
     }
-    if (!is.na(eryt)) {
+    if (!is.null(eryt)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$fullname %like% "^Streptococcus pneumoniae"
@@ -746,7 +814,7 @@ eucast_rules <- function(tbl,
                             & tbl[, eryt] == 'R'),
                cols = c(azit, clar, roxi))
     }
-    if (!is.na(tetr)) {
+    if (!is.null(tetr)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$fullname %like% "^Streptococcus pneumoniae"
@@ -768,14 +836,14 @@ eucast_rules <- function(tbl,
                         "intermedius", "mitis", "mutans", "oligofermentans", "oralis",
                         "parasanguinis", "peroris", "pseudopneumoniae", "salivarius",
                         "sanguinis", "sinensis", "sobrinus", "thermophilus", "vestibularis")
-    if (!is.na(peni)) {
+    if (!is.null(peni)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$genus == "Streptococcus" & tbl$species %in% viridans_group
                             & tbl[, peni] == 'S'),
                cols = c(ampi, amox, amcl, pipe, pita))
     }
-    if (!is.na(ampi)) {
+    if (!is.null(ampi)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$genus == "Streptococcus" & tbl$species %in% viridans_group
@@ -802,7 +870,7 @@ eucast_rules <- function(tbl,
       changed_results <- 0
       cat(rule)
     }
-    if (!is.na(ampi)) {
+    if (!is.null(ampi)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$fullname %like% "^Haemophilus influenzae"
@@ -819,14 +887,14 @@ eucast_rules <- function(tbl,
                             & tbl[, ampi] == 'R'),
                cols = c(amox, pipe))
     }
-    if (!is.na(peni)) {
+    if (!is.null(peni)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$fullname %like% "^Haemophilus influenzae"
                             & tbl[, peni] == 'S'),
                cols = c(ampi, amox, amcl, pipe, pita))
     }
-    if (!is.na(amcl)) {
+    if (!is.null(amcl)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$fullname %like% "^Haemophilus influenzae"
@@ -843,14 +911,14 @@ eucast_rules <- function(tbl,
                             & tbl[, amcl] == 'R'),
                cols = pita)
     }
-    if (!is.na(nali)) {
+    if (!is.null(nali)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$fullname %like% "^Haemophilus influenzae"
                             & tbl[, nali] == 'S'),
                cols = c(cipr, levo, moxi, oflo))
     }
-    if (!is.na(tetr)) {
+    if (!is.null(tetr)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$fullname %like% "^Haemophilus influenzae"
@@ -867,7 +935,7 @@ eucast_rules <- function(tbl,
       changed_results <- 0
       cat(rule)
     }
-    if (!is.na(amcl)) {
+    if (!is.null(amcl)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$fullname %like% "^Moraxella catarrhalis"
@@ -884,14 +952,14 @@ eucast_rules <- function(tbl,
                             & tbl[, amcl] == 'R'),
                cols = pita)
     }
-    if (!is.na(nali)) {
+    if (!is.null(nali)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$fullname %like% "^Moraxella catarrhalis"
                             & tbl[, nali] == 'S'),
                cols = c(cipr, levo, moxi, oflo))
     }
-    if (!is.na(eryt)) {
+    if (!is.null(eryt)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$fullname %like% "^Moraxella catarrhalis"
@@ -908,7 +976,7 @@ eucast_rules <- function(tbl,
                             & tbl[, eryt] == 'R'),
                cols = c(azit, clar, roxi))
     }
-    if (!is.na(tetr)) {
+    if (!is.null(tetr)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$fullname %like% "^Moraxella catarrhalis"
@@ -925,7 +993,7 @@ eucast_rules <- function(tbl,
       changed_results <- 0
       cat(rule)
     }
-    if (!is.na(peni)) {
+    if (!is.null(peni)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$genus %in% c("Clostridium", "Actinomyces", "Propionibacterium",
@@ -961,7 +1029,7 @@ eucast_rules <- function(tbl,
       changed_results <- 0
       cat(rule)
     }
-    if (!is.na(peni)) {
+    if (!is.null(peni)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$genus %in% c("Bacteroides", "Prevotella", "Porphyromonas",
@@ -991,7 +1059,7 @@ eucast_rules <- function(tbl,
       changed_results <- 0
       cat(rule)
     }
-    if (!is.na(peni)) {
+    if (!is.null(peni)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$fullname %like% "^Pasteurella multocida"
@@ -1018,7 +1086,7 @@ eucast_rules <- function(tbl,
       changed_results <- 0
       cat(rule)
     }
-    if (!is.na(eryt)) {
+    if (!is.null(eryt)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$fullname %like% "^Campylobacter (jejuni|coli)"
@@ -1035,7 +1103,7 @@ eucast_rules <- function(tbl,
                             & tbl[, eryt] == 'R'),
                cols = c(azit, clar))
     }
-    if (!is.na(tetr)) {
+    if (!is.null(tetr)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$fullname %like% "^Campylobacter (jejuni|coli)"
@@ -1062,7 +1130,7 @@ eucast_rules <- function(tbl,
       changed_results <- 0
       cat(rule)
     }
-    if (!is.na(norf)) {
+    if (!is.null(norf)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$fullname %like% "^Aerococcus (sanguinicola|urinae)"
@@ -1079,7 +1147,7 @@ eucast_rules <- function(tbl,
                             & tbl[, norf] == 'R'),
                cols = fluoroquinolones)
     }
-    if (!is.na(cipr)) {
+    if (!is.null(cipr)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$fullname %like% "^Aerococcus (sanguinicola|urinae)"
@@ -1106,7 +1174,7 @@ eucast_rules <- function(tbl,
       changed_results <- 0
       cat(rule)
     }
-    if (!is.na(peni)) {
+    if (!is.null(peni)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$fullname %like% "^Kingella kingae"
@@ -1123,7 +1191,7 @@ eucast_rules <- function(tbl,
                             & tbl[, peni] == 'R'),
                cols = c(ampi, amox))
     }
-    if (!is.na(eryt)) {
+    if (!is.null(eryt)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$fullname %like% "^Kingella kingae"
@@ -1140,7 +1208,7 @@ eucast_rules <- function(tbl,
                             & tbl[, eryt] == 'R'),
                cols = c(azit, clar))
     }
-    if (!is.na(tetr)) {
+    if (!is.null(tetr)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$fullname %like% "^Kingella kingae"
@@ -1442,7 +1510,7 @@ eucast_rules <- function(tbl,
       cat(rule)
     }
     # rule 8.3
-    if (!is.na(peni)) {
+    if (!is.null(peni)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl$fullname %like% '^Streptococcus (pyogenes|agalactiae|dysgalactiae|group A|group B|group C|group G)'
@@ -1450,14 +1518,14 @@ eucast_rules <- function(tbl,
                cols = c(aminopenicillins, cephalosporins, carbapenems))
     }
     # rule 8.6
-    if (!is.na(ampi)) {
+    if (!is.null(ampi)) {
       edit_rsi(to = 'R',
                rule = c(rule_group, rule),
                rows = which(tbl$genus == 'Enterococcus'
                             & tbl[, ampi] == 'R'),
                cols = c(ureidopenicillins, carbapenems))
     }
-    if (!is.na(amox)) {
+    if (!is.null(amox)) {
       edit_rsi(to = 'R',
                rule = c(rule_group, rule),
                rows = which(tbl$genus == 'Enterococcus'
@@ -1476,7 +1544,7 @@ eucast_rules <- function(tbl,
       cat(rule)
     }
     # rule 9.3
-    if (!is.na(tica) & !is.na(pipe)) {
+    if (!is.null(tica) & !is.null(pipe)) {
       edit_rsi(to = 'R',
                rule = c(rule_group, rule),
                rows = which(tbl$family == 'Enterobacteriaceae'
@@ -1496,7 +1564,7 @@ eucast_rules <- function(tbl,
       cat(rule)
     }
     # rule 10.2
-    # if (!is.na(ampi)) {
+    # if (!is.null(ampi)) {
     # you should know first if the are B-lactamase positive, so do not run for now
     # edit_rsi(to = 'R',
     #          rule = c(rule_group, rule),
@@ -1516,7 +1584,7 @@ eucast_rules <- function(tbl,
       cat(rule)
     }
     # rule 11.1
-    if (!is.na(eryt)) {
+    if (!is.null(eryt)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl[, eryt] == 'S'),
@@ -1542,7 +1610,7 @@ eucast_rules <- function(tbl,
       cat(rule)
     }
     # rule 12.2
-    if (!is.na(tobr)) {
+    if (!is.null(tobr)) {
       edit_rsi(to = 'R',
                rule = c(rule_group, rule),
                rows = which(tbl$genus == 'Staphylococcus'
@@ -1550,7 +1618,7 @@ eucast_rules <- function(tbl,
                cols = c(kana, amik))
     }
     # rule 12.3
-    if (!is.na(gent)) {
+    if (!is.null(gent)) {
       edit_rsi(to = 'R',
                rule = c(rule_group, rule),
                rows = which(tbl$genus == 'Staphylococcus'
@@ -1558,7 +1626,7 @@ eucast_rules <- function(tbl,
                cols = aminoglycosides)
     }
     # rule 12.8
-    if (!is.na(gent) & !is.na(tobr)) {
+    if (!is.null(gent) & !is.null(tobr)) {
       edit_rsi(to = 'R',
                rule = c(rule_group, rule),
                rows = which(tbl$family == 'Enterobacteriaceae'
@@ -1567,7 +1635,7 @@ eucast_rules <- function(tbl,
                cols = gent)
     }
     # rule 12.9
-    if (!is.na(gent) & !is.na(tobr)) {
+    if (!is.null(gent) & !is.null(tobr)) {
       edit_rsi(to = 'R',
                rule = c(rule_group, rule),
                rows = which(tbl$family == 'Enterobacteriaceae'
@@ -1588,7 +1656,7 @@ eucast_rules <- function(tbl,
       cat(rule)
     }
     # rule 13.2
-    if (!is.na(moxi)) {
+    if (!is.null(moxi)) {
       edit_rsi(to = 'R',
                rule = c(rule_group, rule),
                rows = which(tbl$genus == 'Staphylococcus'
@@ -1596,7 +1664,7 @@ eucast_rules <- function(tbl,
                cols = fluoroquinolones)
     }
     # rule 13.4
-    if (!is.na(moxi)) {
+    if (!is.null(moxi)) {
       edit_rsi(to = 'R',
                rule = c(rule_group, rule),
                rows = which(tbl$fullname %like% '^Streptococcus pneumoniae'
@@ -1604,7 +1672,7 @@ eucast_rules <- function(tbl,
                cols = fluoroquinolones)
     }
     # rule 13.5
-    if (!is.na(cipr)) {
+    if (!is.null(cipr)) {
       edit_rsi(to = 'R',
                rule = c(rule_group, rule),
                rows = which(tbl$family == 'Enterobacteriaceae'
@@ -1612,7 +1680,7 @@ eucast_rules <- function(tbl,
                cols = fluoroquinolones)
     }
     # rule 13.8
-    if (!is.na(cipr)) {
+    if (!is.null(cipr)) {
       edit_rsi(to = 'R',
                rule = c(rule_group, rule),
                rows = which(tbl$fullname %like% '^Neisseria gonorrhoeae'
@@ -1639,7 +1707,7 @@ eucast_rules <- function(tbl,
       changed_results <- 0
       cat(rule)
     }
-    if (!is.na(amcl)) {
+    if (!is.null(amcl)) {
       edit_rsi(to = 'R',
                rule = c(rule_group, rule),
                rows = which(tbl[, amcl] == 'R'),
@@ -1654,7 +1722,7 @@ eucast_rules <- function(tbl,
       changed_results <- 0
       cat(rule)
     }
-    if (!is.na(pita)) {
+    if (!is.null(pita)) {
       edit_rsi(to = 'R',
                rule = c(rule_group, rule),
                rows = which(tbl[, pita] == 'R'),
@@ -1669,7 +1737,7 @@ eucast_rules <- function(tbl,
       changed_results <- 0
       cat(rule)
     }
-    if (!is.na(trsu)) {
+    if (!is.null(trsu)) {
       edit_rsi(to = 'R',
                rule = c(rule_group, rule),
                rows = which(tbl[, trsu] == 'R'),
@@ -1684,7 +1752,7 @@ eucast_rules <- function(tbl,
       changed_results <- 0
       cat(rule)
     }
-    if (!is.na(ampi)) {
+    if (!is.null(ampi)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl[, ampi] == 'S'),
@@ -1699,7 +1767,7 @@ eucast_rules <- function(tbl,
       changed_results <- 0
       cat(rule)
     }
-    if (!is.na(pipe)) {
+    if (!is.null(pipe)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl[, pipe] == 'S'),
@@ -1714,7 +1782,7 @@ eucast_rules <- function(tbl,
       changed_results <- 0
       cat(rule)
     }
-    if (!is.na(trim)) {
+    if (!is.null(trim)) {
       edit_rsi(to = 'S',
                rule = c(rule_group, rule),
                rows = which(tbl[, trim] == 'S'),
@@ -1737,7 +1805,7 @@ eucast_rules <- function(tbl,
     } else {
       wouldve <- ""
     }
-    if (amount_changed == 0) {
+    if (number_changed == 0) {
       colour <- green
     } else {
       colour <- blue
@@ -1745,11 +1813,11 @@ eucast_rules <- function(tbl,
     decimal.mark <- getOption("OutDec")
     big.mark <- ifelse(decimal.mark != ",", ",", ".")
     cat(bold(paste('\n=> EUCAST rules', paste0(wouldve, 'affected'),
-             amount_affected_rows %>% length() %>% format(big.mark = big.mark, decimal.mark = decimal.mark),
+             number_affected_rows %>% length() %>% format(big.mark = big.mark, decimal.mark = decimal.mark),
              'out of', nrow(tbl_original) %>% format(big.mark = big.mark, decimal.mark = decimal.mark),
              'rows ->',
              colour(paste0(wouldve, 'changed'),
-                    amount_changed %>% format(big.mark = big.mark, decimal.mark = decimal.mark), 'test results.\n\n'))))
+                    number_changed %>% format(big.mark = big.mark, decimal.mark = decimal.mark), 'test results.\n\n'))))
   }
 
   if (verbose == TRUE) {
diff --git a/R/guess_ab.R b/R/guess_ab.R
new file mode 100644
index 00000000..70fd6dab
--- /dev/null
+++ b/R/guess_ab.R
@@ -0,0 +1,76 @@
+# ==================================================================== #
+# TITLE                                                                #
+# Antimicrobial Resistance (AMR) Analysis                              #
+#                                                                      #
+# SOURCE                                                               #
+# https://gitlab.com/msberends/AMR                                     #
+#                                                                      #
+# LICENCE                                                              #
+# (c) 2019 Berends MS (m.s.berends@umcg.nl), Luz CF (c.f.luz@umcg.nl)  #
+#                                                                      #
+# This R package is free software; you can freely use and distribute   #
+# it for both personal and commercial purposes under the terms of the  #
+# GNU General Public License version 2.0 (GNU GPL-2), as published by  #
+# the Free Software Foundation.                                        #
+#                                                                      #
+# This R package was created for academic research and was publicly    #
+# released in the hope that it will be useful, but it comes WITHOUT    #
+# ANY WARRANTY OR LIABILITY.                                           #
+# Visit our website for more info: https://msberends.gitab.io/AMR.     #
+# ==================================================================== #
+
+#' Guess antibiotic column
+#'
+#' This tries to find a column name in a data set based on information from the \code{\link{antibiotics}} data set.
+#' @param tbl a \code{data.frame}
+#' @param col a character to look for
+#' @param verbose a logical to indicate whether additional info should be printed
+#' @importFrom dplyr %>% select filter_all any_vars
+#' @export
+#' @inheritSection AMR Read more on our website!
+# @examples
+#
+guess_ab <- function(tbl = NULL, col = NULL, verbose = FALSE) {
+  if (is.null(tbl) & is.null(col)) {
+    return(as.name("guess_ab"))
+  }
+  #stop("This function should not be called directly.")
+  if (length(col) > 1) {
+    warning("argument 'col' has length > 1 and only the first element will be used")
+    col <- col[1]
+  }
+  if (!is.data.frame(tbl)) {
+    stop("`tbl` must be a data.frame")
+  }
+  tbl_names <- colnames(tbl)
+  ab_result <- antibiotics %>%
+    select(atc:trade_name) %>%
+    filter_all(any_vars(tolower(.) == tolower(col)))
+  if (nrow(ab_result) > 1) {
+    # get most likely one
+    if (col %in% ab_result$atc) {
+      ab_result <- ab_result %>% filter(atc == col)
+    } else if (col %in% ab_result$certe) {
+      ab_result <- ab_result %>% filter(certe == col)
+    } else if (col %in% ab_result$umcg) {
+      ab_result <- ab_result %>% filter(umcg == col)
+    } else if (col %in% ab_result$umcg) {
+      ab_result <- ab_result %>% filter(official == col)
+    } else {
+      ab_result <- ab_result[1,]
+    }
+  }
+  tbl_result <- tbl_names[tbl_names %in% ab_result]
+  if (length(tbl_result) > 1) {
+    tbl_result <- tbl_result[1]
+    warning('using column `', tbl_result, '` for col "', col, '"', call. = FALSE)
+  } else if (length(tbl_result) == 0) {
+    if (verbose == TRUE) {
+      message('no result found for col "', col, '"')
+    }
+    return(NULL)
+  } else if (verbose == TRUE) {
+    message('using column `', tbl_result, '` for col "', col, '"')
+  }
+  tbl_result
+}
diff --git a/R/key_antibiotics.R b/R/key_antibiotics.R
index 716e7780..9b37438e 100644
--- a/R/key_antibiotics.R
+++ b/R/key_antibiotics.R
@@ -78,24 +78,24 @@
 #' # FALSE, because I is not ignored and so the 4th value differs
 key_antibiotics <- function(tbl,
                             col_mo = NULL,
-                            universal_1 = "amox",
-                            universal_2 = "amcl",
-                            universal_3 = "cfur",
-                            universal_4 = "pita",
-                            universal_5 = "cipr",
-                            universal_6 = "trsu",
-                            GramPos_1 = "vanc",
-                            GramPos_2 = "teic",
-                            GramPos_3 = "tetr",
-                            GramPos_4 = "eryt",
-                            GramPos_5 = "oxac",
-                            GramPos_6 = "rifa",
-                            GramNeg_1 = "gent",
-                            GramNeg_2 = "tobr",
-                            GramNeg_3 = "coli",
-                            GramNeg_4 = "cfot",
-                            GramNeg_5 = "cfta",
-                            GramNeg_6 = "mero",
+                            universal_1 = guess_ab(tbl, "amox"),
+                            universal_2 = guess_ab(tbl, "amcl"),
+                            universal_3 = guess_ab(tbl, "cfur"),
+                            universal_4 = guess_ab(tbl, "pita"),
+                            universal_5 = guess_ab(tbl, "cipr"),
+                            universal_6 = guess_ab(tbl, "trsu"),
+                            GramPos_1 = guess_ab(tbl, "vanc"),
+                            GramPos_2 = guess_ab(tbl, "teic"),
+                            GramPos_3 = guess_ab(tbl, "tetr"),
+                            GramPos_4 = guess_ab(tbl, "eryt"),
+                            GramPos_5 = guess_ab(tbl, "oxac"),
+                            GramPos_6 = guess_ab(tbl, "rifa"),
+                            GramNeg_1 = guess_ab(tbl, "gent"),
+                            GramNeg_2 = guess_ab(tbl, "tobr"),
+                            GramNeg_3 = guess_ab(tbl, "coli"),
+                            GramNeg_4 = guess_ab(tbl, "cfot"),
+                            GramNeg_5 = guess_ab(tbl, "cfta"),
+                            GramNeg_6 = guess_ab(tbl, "mero"),
                             warnings = TRUE,
                             ...) {
 
@@ -114,6 +114,7 @@ key_antibiotics <- function(tbl,
                 GramPos_1, GramPos_2, GramPos_3, GramPos_4, GramPos_5, GramPos_6,
                 GramNeg_1, GramNeg_2, GramNeg_3, GramNeg_4, GramNeg_5, GramNeg_6)
   col.list <- check_available_columns(tbl = tbl, col.list = col.list, info = warnings)
+  print(col.list)
   universal_1 <- col.list[universal_1]
   universal_2 <- col.list[universal_2]
   universal_3 <- col.list[universal_3]
@@ -139,12 +140,12 @@ key_antibiotics <- function(tbl,
   gram_positive = c(universal,
                     GramPos_1, GramPos_2, GramPos_3,
                     GramPos_4, GramPos_5, GramPos_6)
-  gram_positive <- gram_positive[!is.na(gram_positive)]
+  gram_positive <- gram_positive[!is.null(gram_positive)]
 
   gram_negative = c(universal,
                     GramNeg_1, GramNeg_2, GramNeg_3,
                     GramNeg_4, GramNeg_5, GramNeg_6)
-  gram_negative <- gram_negative[!is.na(gram_negative)]
+  gram_negative <- gram_negative[!is.null(gram_negative)]
 
   # join to microorganisms data set
   tbl <- tbl %>%
@@ -152,6 +153,9 @@ key_antibiotics <- function(tbl,
     left_join_microorganisms(by = col_mo) %>%
     mutate(key_ab = NA_character_)
 
+  print(as.character(gram_positive))
+  print(gram_negative)
+
   # Gram +
   tbl <- tbl %>% mutate(key_ab =
                           if_else(gramstain == "Gram positive",
diff --git a/R/mdro.R b/R/mdro.R
index 6d2f6b5f..09deedcd 100755
--- a/R/mdro.R
+++ b/R/mdro.R
@@ -46,66 +46,66 @@ mdro <- function(tbl,
                  country = NULL,
                  col_mo = NULL,
                  info = TRUE,
-                 amcl = 'amcl',
-                 amik = 'amik',
-                 amox = 'amox',
-                 ampi = 'ampi',
-                 azit = 'azit',
-                 aztr = 'aztr',
-                 cefa = 'cefa',
-                 cfra = 'cfra',
-                 cfep = 'cfep',
-                 cfot = 'cfot',
-                 cfox = 'cfox',
-                 cfta = 'cfta',
-                 cftr = 'cftr',
-                 cfur = 'cfur',
-                 chlo = 'chlo',
-                 cipr = 'cipr',
-                 clar = 'clar',
-                 clin = 'clin',
-                 clox = 'clox',
-                 coli = 'coli',
-                 czol = 'czol',
-                 dapt = 'dapt',
-                 doxy = 'doxy',
-                 erta = 'erta',
-                 eryt = 'eryt',
-                 fosf = 'fosf',
-                 fusi = 'fusi',
-                 gent = 'gent',
-                 imip = 'imip',
-                 kana = 'kana',
-                 levo = 'levo',
-                 linc = 'linc',
-                 line = 'line',
-                 mero = 'mero',
-                 metr = 'metr',
-                 mino = 'mino',
-                 moxi = 'moxi',
-                 nali = 'nali',
-                 neom = 'neom',
-                 neti = 'neti',
-                 nitr = 'nitr',
-                 novo = 'novo',
-                 norf = 'norf',
-                 oflo = 'oflo',
-                 peni = 'peni',
-                 pipe = 'pipe',
-                 pita = 'pita',
-                 poly = 'poly',
-                 qida = 'qida',
-                 rifa = 'rifa',
-                 roxi = 'roxi',
-                 siso = 'siso',
-                 teic = 'teic',
-                 tetr = 'tetr',
-                 tica = 'tica',
-                 tige = 'tige',
-                 tobr = 'tobr',
-                 trim = 'trim',
-                 trsu = 'trsu',
-                 vanc = 'vanc') {
+                 amcl = guess_ab(),
+                 amik = guess_ab(),
+                 amox = guess_ab(),
+                 ampi = guess_ab(),
+                 azit = guess_ab(),
+                 aztr = guess_ab(),
+                 cefa = guess_ab(),
+                 cfra = guess_ab(),
+                 cfep = guess_ab(),
+                 cfot = guess_ab(),
+                 cfox = guess_ab(),
+                 cfta = guess_ab(),
+                 cftr = guess_ab(),
+                 cfur = guess_ab(),
+                 chlo = guess_ab(),
+                 cipr = guess_ab(),
+                 clar = guess_ab(),
+                 clin = guess_ab(),
+                 clox = guess_ab(),
+                 coli = guess_ab(),
+                 czol = guess_ab(),
+                 dapt = guess_ab(),
+                 doxy = guess_ab(),
+                 erta = guess_ab(),
+                 eryt = guess_ab(),
+                 fosf = guess_ab(),
+                 fusi = guess_ab(),
+                 gent = guess_ab(),
+                 imip = guess_ab(),
+                 kana = guess_ab(),
+                 levo = guess_ab(),
+                 linc = guess_ab(),
+                 line = guess_ab(),
+                 mero = guess_ab(),
+                 metr = guess_ab(),
+                 mino = guess_ab(),
+                 moxi = guess_ab(),
+                 nali = guess_ab(),
+                 neom = guess_ab(),
+                 neti = guess_ab(),
+                 nitr = guess_ab(),
+                 novo = guess_ab(),
+                 norf = guess_ab(),
+                 oflo = guess_ab(),
+                 peni = guess_ab(),
+                 pipe = guess_ab(),
+                 pita = guess_ab(),
+                 poly = guess_ab(),
+                 qida = guess_ab(),
+                 rifa = guess_ab(),
+                 roxi = guess_ab(),
+                 siso = guess_ab(),
+                 teic = guess_ab(),
+                 tetr = guess_ab(),
+                 tica = guess_ab(),
+                 tige = guess_ab(),
+                 tobr = guess_ab(),
+                 trim = guess_ab(),
+                 trsu = guess_ab(),
+                 vanc = guess_ab()) {
 
   if (!is.data.frame(tbl)) {
     stop("`tbl` must be a data frame.", call. = FALSE)
@@ -169,12 +169,77 @@ mdro <- function(tbl,
   }
 
   # check columns
+  if (identical(amcl, as.name("guess_ab"))) { amcl <- guess_ab(tbl, "amcl", verbose = info) }
+  if (identical(amik, as.name("guess_ab"))) { amik <- guess_ab(tbl, "amik", verbose = info) }
+  if (identical(amox, as.name("guess_ab"))) { amox <- guess_ab(tbl, "amox", verbose = info) }
+  if (identical(ampi, as.name("guess_ab"))) { ampi <- guess_ab(tbl, "ampi", verbose = info) }
+  if (identical(azit, as.name("guess_ab"))) { azit <- guess_ab(tbl, "azit", verbose = info) }
+  if (identical(aztr, as.name("guess_ab"))) { aztr <- guess_ab(tbl, "aztr", verbose = info) }
+  if (identical(cefa, as.name("guess_ab"))) { cefa <- guess_ab(tbl, "cefa", verbose = info) }
+  if (identical(cfra, as.name("guess_ab"))) { cfra <- guess_ab(tbl, "cfra", verbose = info) }
+  if (identical(cfep, as.name("guess_ab"))) { cfep <- guess_ab(tbl, "cfep", verbose = info) }
+  if (identical(cfot, as.name("guess_ab"))) { cfot <- guess_ab(tbl, "cfot", verbose = info) }
+  if (identical(cfox, as.name("guess_ab"))) { cfox <- guess_ab(tbl, "cfox", verbose = info) }
+  if (identical(cfta, as.name("guess_ab"))) { cfta <- guess_ab(tbl, "cfta", verbose = info) }
+  if (identical(cftr, as.name("guess_ab"))) { cftr <- guess_ab(tbl, "cftr", verbose = info) }
+  if (identical(cfur, as.name("guess_ab"))) { cfur <- guess_ab(tbl, "cfur", verbose = info) }
+  if (identical(chlo, as.name("guess_ab"))) { chlo <- guess_ab(tbl, "chlo", verbose = info) }
+  if (identical(cipr, as.name("guess_ab"))) { cipr <- guess_ab(tbl, "cipr", verbose = info) }
+  if (identical(clar, as.name("guess_ab"))) { clar <- guess_ab(tbl, "clar", verbose = info) }
+  if (identical(clin, as.name("guess_ab"))) { clin <- guess_ab(tbl, "clin", verbose = info) }
+  if (identical(clox, as.name("guess_ab"))) { clox <- guess_ab(tbl, "clox", verbose = info) }
+  if (identical(coli, as.name("guess_ab"))) { coli <- guess_ab(tbl, "coli", verbose = info) }
+  if (identical(czol, as.name("guess_ab"))) { czol <- guess_ab(tbl, "czol", verbose = info) }
+  if (identical(dapt, as.name("guess_ab"))) { dapt <- guess_ab(tbl, "dapt", verbose = info) }
+  if (identical(doxy, as.name("guess_ab"))) { doxy <- guess_ab(tbl, "doxy", verbose = info) }
+  if (identical(erta, as.name("guess_ab"))) { erta <- guess_ab(tbl, "erta", verbose = info) }
+  if (identical(eryt, as.name("guess_ab"))) { eryt <- guess_ab(tbl, "eryt", verbose = info) }
+  if (identical(fosf, as.name("guess_ab"))) { fosf <- guess_ab(tbl, "fosf", verbose = info) }
+  if (identical(fusi, as.name("guess_ab"))) { fusi <- guess_ab(tbl, "fusi", verbose = info) }
+  if (identical(gent, as.name("guess_ab"))) { gent <- guess_ab(tbl, "gent", verbose = info) }
+  if (identical(imip, as.name("guess_ab"))) { imip <- guess_ab(tbl, "imip", verbose = info) }
+  if (identical(kana, as.name("guess_ab"))) { kana <- guess_ab(tbl, "kana", verbose = info) }
+  if (identical(levo, as.name("guess_ab"))) { levo <- guess_ab(tbl, "levo", verbose = info) }
+  if (identical(linc, as.name("guess_ab"))) { linc <- guess_ab(tbl, "linc", verbose = info) }
+  if (identical(line, as.name("guess_ab"))) { line <- guess_ab(tbl, "line", verbose = info) }
+  if (identical(mero, as.name("guess_ab"))) { mero <- guess_ab(tbl, "mero", verbose = info) }
+  if (identical(metr, as.name("guess_ab"))) { metr <- guess_ab(tbl, "metr", verbose = info) }
+  if (identical(mino, as.name("guess_ab"))) { mino <- guess_ab(tbl, "mino", verbose = info) }
+  if (identical(moxi, as.name("guess_ab"))) { moxi <- guess_ab(tbl, "moxi", verbose = info) }
+  if (identical(nali, as.name("guess_ab"))) { nali <- guess_ab(tbl, "nali", verbose = info) }
+  if (identical(neom, as.name("guess_ab"))) { neom <- guess_ab(tbl, "neom", verbose = info) }
+  if (identical(neti, as.name("guess_ab"))) { neti <- guess_ab(tbl, "neti", verbose = info) }
+  if (identical(nitr, as.name("guess_ab"))) { nitr <- guess_ab(tbl, "nitr", verbose = info) }
+  if (identical(novo, as.name("guess_ab"))) { novo <- guess_ab(tbl, "novo", verbose = info) }
+  if (identical(norf, as.name("guess_ab"))) { norf <- guess_ab(tbl, "norf", verbose = info) }
+  if (identical(oflo, as.name("guess_ab"))) { oflo <- guess_ab(tbl, "oflo", verbose = info) }
+  if (identical(peni, as.name("guess_ab"))) { peni <- guess_ab(tbl, "peni", verbose = info) }
+  if (identical(pipe, as.name("guess_ab"))) { pipe <- guess_ab(tbl, "pipe", verbose = info) }
+  if (identical(pita, as.name("guess_ab"))) { pita <- guess_ab(tbl, "pita", verbose = info) }
+  if (identical(poly, as.name("guess_ab"))) { poly <- guess_ab(tbl, "poly", verbose = info) }
+  if (identical(qida, as.name("guess_ab"))) { qida <- guess_ab(tbl, "qida", verbose = info) }
+  if (identical(rifa, as.name("guess_ab"))) { rifa <- guess_ab(tbl, "rifa", verbose = info) }
+  if (identical(roxi, as.name("guess_ab"))) { roxi <- guess_ab(tbl, "roxi", verbose = info) }
+  if (identical(siso, as.name("guess_ab"))) { siso <- guess_ab(tbl, "siso", verbose = info) }
+  if (identical(teic, as.name("guess_ab"))) { teic <- guess_ab(tbl, "teic", verbose = info) }
+  if (identical(tetr, as.name("guess_ab"))) { tetr <- guess_ab(tbl, "tetr", verbose = info) }
+  if (identical(tica, as.name("guess_ab"))) { tica <- guess_ab(tbl, "tica", verbose = info) }
+  if (identical(tige, as.name("guess_ab"))) { tige <- guess_ab(tbl, "tige", verbose = info) }
+  if (identical(tobr, as.name("guess_ab"))) { tobr <- guess_ab(tbl, "tobr", verbose = info) }
+  if (identical(trim, as.name("guess_ab"))) { trim <- guess_ab(tbl, "trim", verbose = info) }
+  if (identical(trsu, as.name("guess_ab"))) { trsu <- guess_ab(tbl, "trsu", verbose = info) }
+  if (identical(vanc, as.name("guess_ab"))) { vanc <- guess_ab(tbl, "vanc", verbose = info) }
   col.list <- c(amcl, amik, amox, ampi, azit, aztr, cefa, cfra, cfep, cfot,
                 cfox, cfta, cftr, cfur, chlo, cipr, clar, clin, clox, coli,
                 czol, dapt, doxy, erta, eryt, fosf, fusi, gent, imip, kana,
-                levo, linc, line, mero, metr, mino, moxi, nali, neom, neti, nitr,
-                novo, norf, oflo, peni, pita, poly, qida, rifa, roxi, siso,
-                teic, tetr, tica, tige, tobr, trim, trsu, vanc)
+                levo, linc, line, mero, metr, mino, moxi, nali, neom, neti,
+                nitr, novo, norf, oflo, peni, pipe, pita, poly, qida, rifa,
+                roxi, siso, teic, tetr, tica, tige, tobr, trim, trsu, vanc)
+  if (length(col.list) < 60) {
+    warning('Some columns do not exist -- THIS MAY STRONGLY INFLUENCE THE OUTCOME.',
+            immediate. = TRUE,
+            call. = FALSE)
+  }
   col.list <- check_available_columns(tbl = tbl, col.list = col.list, info = info)
   amcl <- col.list[amcl]
   amik <- col.list[amik]
@@ -221,6 +286,7 @@ mdro <- function(tbl,
   norf <- col.list[norf]
   oflo <- col.list[oflo]
   peni <- col.list[peni]
+  pipe <- col.list[pipe]
   pita <- col.list[pita]
   poly <- col.list[poly]
   qida <- col.list[qida]
diff --git a/R/misc.R b/R/misc.R
index 86c7c06e..c2b17c6a 100755
--- a/R/misc.R
+++ b/R/misc.R
@@ -80,7 +80,7 @@ check_available_columns <- function(tbl, col.list, info = TRUE) {
     } else if (tolower(col.list[i]) %in% colnames(tbl)) {
       col.list[i] <- tolower(col.list[i])
     } else if (!col.list[i] %in% colnames(tbl)) {
-      col.list[i] <- NA
+      col.list[i] <- NULL
     }
   }
   if (!all(col.list %in% colnames(tbl))) {
diff --git a/man/eucast_rules.Rd b/man/eucast_rules.Rd
index 53475be6..33d13699 100644
--- a/man/eucast_rules.Rd
+++ b/man/eucast_rules.Rd
@@ -25,22 +25,27 @@
 \usage{
 eucast_rules(tbl, col_mo = NULL, info = TRUE,
   rules = c("breakpoints", "expert", "other", "all"), verbose = FALSE,
-  amcl = "amcl", amik = "amik", amox = "amox", ampi = "ampi",
-  azit = "azit", azlo = "azlo", aztr = "aztr", cefa = "cefa",
-  cfep = "cfep", cfot = "cfot", cfox = "cfox", cfra = "cfra",
-  cfta = "cfta", cftr = "cftr", cfur = "cfur", chlo = "chlo",
-  cipr = "cipr", clar = "clar", clin = "clin", clox = "clox",
-  coli = "coli", czol = "czol", dapt = "dapt", doxy = "doxy",
-  erta = "erta", eryt = "eryt", fosf = "fosf", fusi = "fusi",
-  gent = "gent", imip = "imip", kana = "kana", levo = "levo",
-  linc = "linc", line = "line", mero = "mero", mezl = "mezl",
-  mino = "mino", moxi = "moxi", nali = "nali", neom = "neom",
-  neti = "neti", nitr = "nitr", norf = "norf", novo = "novo",
-  oflo = "oflo", oxac = "oxac", peni = "peni", pipe = "pipe",
-  pita = "pita", poly = "poly", pris = "pris", qida = "qida",
-  rifa = "rifa", roxi = "roxi", siso = "siso", teic = "teic",
-  tetr = "tetr", tica = "tica", tige = "tige", tobr = "tobr",
-  trim = "trim", trsu = "trsu", vanc = "vanc")
+  amcl = guess_ab(), amik = guess_ab(), amox = guess_ab(),
+  ampi = guess_ab(), azit = guess_ab(), azlo = guess_ab(),
+  aztr = guess_ab(), cefa = guess_ab(), cfep = guess_ab(),
+  cfot = guess_ab(), cfox = guess_ab(), cfra = guess_ab(),
+  cfta = guess_ab(), cftr = guess_ab(), cfur = guess_ab(),
+  chlo = guess_ab(), cipr = guess_ab(), clar = guess_ab(),
+  clin = guess_ab(), clox = guess_ab(), coli = guess_ab(),
+  czol = guess_ab(), dapt = guess_ab(), doxy = guess_ab(),
+  erta = guess_ab(), eryt = guess_ab(), fosf = guess_ab(),
+  fusi = guess_ab(), gent = guess_ab(), imip = guess_ab(),
+  kana = guess_ab(), levo = guess_ab(), linc = guess_ab(),
+  line = guess_ab(), mero = guess_ab(), mezl = guess_ab(),
+  mino = guess_ab(), moxi = guess_ab(), nali = guess_ab(),
+  neom = guess_ab(), neti = guess_ab(), nitr = guess_ab(),
+  norf = guess_ab(), novo = guess_ab(), oflo = guess_ab(),
+  oxac = guess_ab(), peni = guess_ab(), pipe = guess_ab(),
+  pita = guess_ab(), poly = guess_ab(), pris = guess_ab(),
+  qida = guess_ab(), rifa = guess_ab(), roxi = guess_ab(),
+  siso = guess_ab(), teic = guess_ab(), tetr = guess_ab(),
+  tica = guess_ab(), tige = guess_ab(), tobr = guess_ab(),
+  trim = guess_ab(), trsu = guess_ab(), vanc = guess_ab())
 
 EUCAST_rules(...)
 
@@ -69,7 +74,7 @@ Apply susceptibility rules as defined by the European Committee on Antimicrobial
 }
 \section{Antibiotics}{
 
-To define antibiotics column names, input a text (case-insensitive) or use \code{NULL} to skip a column (e.g. \code{tica = NULL}). Non-existing columns will anyway be skipped with a warning.
+To define antibiotics column names, leave as it is to determine it automatically with \code{\link{guess_ab}} or input a text (case-insensitive) or use \code{NULL} to skip a column (e.g. \code{tica = NULL}). Non-existing columns will anyway be skipped with a warning.
 
 Abbrevations of the column containing antibiotics in the form: \strong{abbreviation}: generic name (\emph{ATC code})
 
diff --git a/man/guess_ab.Rd b/man/guess_ab.Rd
new file mode 100644
index 00000000..8ce0f929
--- /dev/null
+++ b/man/guess_ab.Rd
@@ -0,0 +1,24 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/guess_ab.R
+\name{guess_ab}
+\alias{guess_ab}
+\title{Guess antibiotic column}
+\usage{
+guess_ab(tbl = NULL, col = NULL, verbose = FALSE)
+}
+\arguments{
+\item{tbl}{a \code{data.frame}}
+
+\item{col}{a character to look for}
+
+\item{verbose}{a logical to indicate whether additional info should be printed}
+}
+\description{
+This tries to find a column name in a data set based on information from the \code{\link{antibiotics}} data set.
+}
+\section{Read more on our website!}{
+
+\if{html}{\figure{logo.png}{options: height=40px style=margin-bottom:5px} \cr}
+On our website \url{https://msberends.gitlab.io/AMR} you can find \href{https://msberends.gitlab.io/AMR/articles/AMR.html}{a omprehensive tutorial} about how to conduct AMR analysis and find \href{https://msberends.gitlab.io/AMR/reference}{the complete documentation of all functions}, which reads a lot easier than in R.
+}
+
diff --git a/man/key_antibiotics.Rd b/man/key_antibiotics.Rd
index ba9758d7..03686a7e 100755
--- a/man/key_antibiotics.Rd
+++ b/man/key_antibiotics.Rd
@@ -5,13 +5,17 @@
 \alias{key_antibiotics_equal}
 \title{Key antibiotics for first \emph{weighted} isolates}
 \usage{
-key_antibiotics(tbl, col_mo = NULL, universal_1 = "amox",
-  universal_2 = "amcl", universal_3 = "cfur", universal_4 = "pita",
-  universal_5 = "cipr", universal_6 = "trsu", GramPos_1 = "vanc",
-  GramPos_2 = "teic", GramPos_3 = "tetr", GramPos_4 = "eryt",
-  GramPos_5 = "oxac", GramPos_6 = "rifa", GramNeg_1 = "gent",
-  GramNeg_2 = "tobr", GramNeg_3 = "coli", GramNeg_4 = "cfot",
-  GramNeg_5 = "cfta", GramNeg_6 = "mero", warnings = TRUE, ...)
+key_antibiotics(tbl, col_mo = NULL, universal_1 = guess_ab(tbl,
+  "amox"), universal_2 = guess_ab(tbl, "amcl"),
+  universal_3 = guess_ab(tbl, "cfur"), universal_4 = guess_ab(tbl,
+  "pita"), universal_5 = guess_ab(tbl, "cipr"),
+  universal_6 = guess_ab(tbl, "trsu"), GramPos_1 = guess_ab(tbl,
+  "vanc"), GramPos_2 = guess_ab(tbl, "teic"), GramPos_3 = guess_ab(tbl,
+  "tetr"), GramPos_4 = guess_ab(tbl, "eryt"), GramPos_5 = guess_ab(tbl,
+  "oxac"), GramPos_6 = guess_ab(tbl, "rifa"), GramNeg_1 = guess_ab(tbl,
+  "gent"), GramNeg_2 = guess_ab(tbl, "tobr"), GramNeg_3 = guess_ab(tbl,
+  "coli"), GramNeg_4 = guess_ab(tbl, "cfot"), GramNeg_5 = guess_ab(tbl,
+  "cfta"), GramNeg_6 = guess_ab(tbl, "mero"), warnings = TRUE, ...)
 
 key_antibiotics_equal(x, y, type = c("keyantibiotics", "points"),
   ignore_I = TRUE, points_threshold = 2, info = FALSE)
diff --git a/man/mdro.Rd b/man/mdro.Rd
index e5c90a8e..a0915e83 100644
--- a/man/mdro.Rd
+++ b/man/mdro.Rd
@@ -8,21 +8,26 @@
 \title{Determine multidrug-resistant organisms (MDRO)}
 \usage{
 mdro(tbl, country = NULL, col_mo = NULL, info = TRUE,
-  amcl = "amcl", amik = "amik", amox = "amox", ampi = "ampi",
-  azit = "azit", aztr = "aztr", cefa = "cefa", cfra = "cfra",
-  cfep = "cfep", cfot = "cfot", cfox = "cfox", cfta = "cfta",
-  cftr = "cftr", cfur = "cfur", chlo = "chlo", cipr = "cipr",
-  clar = "clar", clin = "clin", clox = "clox", coli = "coli",
-  czol = "czol", dapt = "dapt", doxy = "doxy", erta = "erta",
-  eryt = "eryt", fosf = "fosf", fusi = "fusi", gent = "gent",
-  imip = "imip", kana = "kana", levo = "levo", linc = "linc",
-  line = "line", mero = "mero", metr = "metr", mino = "mino",
-  moxi = "moxi", nali = "nali", neom = "neom", neti = "neti",
-  nitr = "nitr", novo = "novo", norf = "norf", oflo = "oflo",
-  peni = "peni", pipe = "pipe", pita = "pita", poly = "poly",
-  qida = "qida", rifa = "rifa", roxi = "roxi", siso = "siso",
-  teic = "teic", tetr = "tetr", tica = "tica", tige = "tige",
-  tobr = "tobr", trim = "trim", trsu = "trsu", vanc = "vanc")
+  amcl = guess_ab(), amik = guess_ab(), amox = guess_ab(),
+  ampi = guess_ab(), azit = guess_ab(), aztr = guess_ab(),
+  cefa = guess_ab(), cfra = guess_ab(), cfep = guess_ab(),
+  cfot = guess_ab(), cfox = guess_ab(), cfta = guess_ab(),
+  cftr = guess_ab(), cfur = guess_ab(), chlo = guess_ab(),
+  cipr = guess_ab(), clar = guess_ab(), clin = guess_ab(),
+  clox = guess_ab(), coli = guess_ab(), czol = guess_ab(),
+  dapt = guess_ab(), doxy = guess_ab(), erta = guess_ab(),
+  eryt = guess_ab(), fosf = guess_ab(), fusi = guess_ab(),
+  gent = guess_ab(), imip = guess_ab(), kana = guess_ab(),
+  levo = guess_ab(), linc = guess_ab(), line = guess_ab(),
+  mero = guess_ab(), metr = guess_ab(), mino = guess_ab(),
+  moxi = guess_ab(), nali = guess_ab(), neom = guess_ab(),
+  neti = guess_ab(), nitr = guess_ab(), novo = guess_ab(),
+  norf = guess_ab(), oflo = guess_ab(), peni = guess_ab(),
+  pipe = guess_ab(), pita = guess_ab(), poly = guess_ab(),
+  qida = guess_ab(), rifa = guess_ab(), roxi = guess_ab(),
+  siso = guess_ab(), teic = guess_ab(), tetr = guess_ab(),
+  tica = guess_ab(), tige = guess_ab(), tobr = guess_ab(),
+  trim = guess_ab(), trsu = guess_ab(), vanc = guess_ab())
 
 brmo(..., country = "nl")
 
@@ -172,7 +177,7 @@ When \code{country} will be left blank, guidelines will be taken from EUCAST Exp
 }
 \section{Antibiotics}{
 
-To define antibiotics column names, input a text (case-insensitive) or use \code{NULL} to skip a column (e.g. \code{tica = NULL}). Non-existing columns will anyway be skipped with a warning.
+To define antibiotics column names, leave as it is to determine it automatically with \code{\link{guess_ab}} or input a text (case-insensitive) or use \code{NULL} to skip a column (e.g. \code{tica = NULL}). Non-existing columns will anyway be skipped with a warning.
 
 Abbrevations of the column containing antibiotics in the form: \strong{abbreviation}: generic name (\emph{ATC code})
 
diff --git a/tests/testthat/test-eucast_rules.R b/tests/testthat/test-eucast_rules.R
index 0127f575..5da53630 100755
--- a/tests/testthat/test-eucast_rules.R
+++ b/tests/testthat/test-eucast_rules.R
@@ -86,12 +86,14 @@ test_that("EUCAST rules work", {
 
   # amox is inferred by benzylpenicillin in Kingella kingae
   expect_equal(
-    as.list(eucast_rules(
-      data.frame(mo = as.mo("Kingella kingae"),
-                 peni = "S",
-                 amox = "-",
-                 stringsAsFactors = FALSE)
-      , info = FALSE))$amox,
+    suppressWarnings(
+      as.list(eucast_rules(
+        data.frame(mo = as.mo("Kingella kingae"),
+                   peni = "S",
+                   amox = "-",
+                   stringsAsFactors = FALSE)
+        , info = FALSE))$amox
+    ),
     "S")
 
   # also test norf
diff --git a/tests/testthat/test-mdro.R b/tests/testthat/test-mdro.R
index 608c902f..1606f590 100755
--- a/tests/testthat/test-mdro.R
+++ b/tests/testthat/test-mdro.R
@@ -42,7 +42,13 @@ test_that("mdro works", {
   expect_equal(outcome %>% freq() %>% pull(count),
                c(1989, 9, 2)) # 1989 neg, 9 pos, 2 unconfirmed
 
-  expect_equal(brmo(septic_patients, info = FALSE), mdro(septic_patients, "nl", info = FALSE))
+  expect_equal(
+    suppressWarnings(
+      brmo(septic_patients, info = FALSE)),
+    suppressWarnings(
+      mdro(septic_patients, "nl", info = FALSE)
+    )
+  )
 
   # still working on German guidelines
   expect_error(suppressWarnings(mrgn(septic_patients, info = TRUE)))