diff --git a/gene_splicer/primer_finder.py b/gene_splicer/primer_finder.py
index 4ebd9a6..dbb741e 100644
--- a/gene_splicer/primer_finder.py
+++ b/gene_splicer/primer_finder.py
@@ -384,10 +384,10 @@ def add_primers(row):
 
 
 def remove_primers(row):
-    # Strip the primers out
+    # Strip the primers out, convert index values from floats.
     newseq = row.sequence[
-             row.fwd_sample_primer_size + row.fwd_sample_primer_start
-             :-(row.rev_sample_primer_size + row.rev_sample_primer_start)]
+             int(row.fwd_sample_primer_size + row.fwd_sample_primer_start)
+             :-int(row.rev_sample_primer_size + row.rev_sample_primer_start)]
     row.sequence = newseq
     return row