diff --git a/bin/cdhit_wrapper.R b/bin/cdhit_wrapper.R
index 71bf881..c5f7230 100644
--- a/bin/cdhit_wrapper.R
+++ b/bin/cdhit_wrapper.R
@@ -68,6 +68,8 @@ opt <- parse_args(opt_parser)
 #' @param gat_ext Gap extension score. Default = -1 (CD-HIT parameter)
 #' @param sort_cluster_by_size Either sort cluster by decreasing length (= 0) or by decreasing size (= 1). Default = 1 (CD-HIT parameter)
 #' 
+#' @details If there is a header supplied other then the default data.table nameing scheme ('V1', 'V2', etc.) it will be kept and extended.
+#' 
 cdhitest <- function(input, identity = 0.8, coverage = 8, output = "cluster.bed", clean = TRUE, threads = 1, global = 0, band_width = 20, memory = 800, word_length = 3, throw_away_sequences = 5, length_dif_cutoff_shorter_p = 0, length_dif_cutoff_shorter_n = 999999, alignment_coverage_longer_p = 0, alignment_coverage_longer_n = 99999999, alignment_coverage_shorter_p = 0, alignment_coverage_shorter_n = 99999999, max_unmatched_longer_p = 1, max_unmatched_shorter_p = 1, max_unmatched_both_n = 99999999, fast_cluster = 1, strand = 0, match = 2, mismatch = -2, gap = -6, gap_ext = -1, sort_cluster_by_size = 1) {
   if (system("which cd-hit-est", ignore.stdout = FALSE) != 0) {
     stop("Required program CD-HIT not found! Please check whether it is installed.")
@@ -80,15 +82,19 @@ cdhitest <- function(input, identity = 0.8, coverage = 8, output = "cluster.bed"
   message("Loading bed.")
   # load bed if neccessary
   if (!data.table::is.data.table(input)) {
-    bed_table <- data.table::fread(input = input, header = FALSE)
+    bed_table <- data.table::fread(input = input)
   } else {
     bed_table <- input
   }
   
+  # check if there are column names to keep them
+  default_col_names <- grepl(pattern = "^V+\\d$", names(bed_table), perl = TRUE)
+  keep_col_names <- ifelse(any(default_col_names), FALSE, TRUE)
+  
   # check for duplicated names
-  if (anyDuplicated(bed_table[, "V4"])) {
+  if (anyDuplicated(bed_table[, 4])) {
     warning("Found duplicated names. Making names unique.")
-    bed_table[, V4 := make.unique(V4)]
+    bed_table[, 4 := make.unique(names(bed_table)[4])]
   }
   
   message("Convert to fasta.")
@@ -140,17 +146,18 @@ cdhitest <- function(input, identity = 0.8, coverage = 8, output = "cluster.bed"
   system(command = cluster_call, wait = TRUE)
   
   # load reformated file
-  cluster <- data.table::fread(cluster_file)
+  cluster <- data.table::fread(cluster_file)[, c("id", "clstr")]
+  names(cluster) <- c("id", "cluster")
   
   ### add cluster to bed_table
-  result <- merge(x = bed_table, y = cluster[, c("id", "clstr")], by.x = "V4", by.y = "id", sort = FALSE)[, union(names(bed_table), names(cluster)[2]), with = FALSE]
+  result <- merge(x = bed_table, y = cluster, by.x = names(bed_table)[4], by.y = "id", sort = FALSE)[, union(names(bed_table), names(cluster)[2]), with = FALSE]
   
   # delete files
   if (clean) {
     file.remove(fasta_file, paste0(cdhit_output, ".clstr"), cdhit_output, cluster_file)
   }
   
-  data.table::fwrite(x = result, file = output, sep = "\t", col.names = FALSE)
+  data.table::fwrite(x = result, file = output, sep = "\t", col.names = keep_col_names)
 }
 
 # call function with given parameter if not in interactive context (e.g. run from shell)