diff --git a/SemiBin/utils.py b/SemiBin/utils.py
index 4b199a3..3b892b3 100644
--- a/SemiBin/utils.py
+++ b/SemiBin/utils.py
@@ -357,7 +357,7 @@ def contig_name(ell):
     else:
         def extract_seeds(vs, sel):
             vs = vs.sort_values()
-            median = vs[len(vs) //2]
+            median = vs.iloc[len(vs) //2]
 
             # the original version broke ties by picking the shortest query, so we
             # replicate that here: