diff --git a/bin/dryad_summary.py b/bin/dryad_summary.py
index 7603601..405c21b 100755
--- a/bin/dryad_summary.py
+++ b/bin/dryad_summary.py
@@ -62,7 +62,7 @@ def join_dfs_with_quast(df_log, df_excluded, df_quast):
     df_log_excluded_quast = pd.merge(df_log_excluded, df_quast, on='Sample', how='outer')
 
     # Change float to int
-    df_log_excluded_quast[['Sequence Length','Cluster Coverage (bps)','Contigs','N50']] = df_log_excluded_quast[['Sequence Length','Cluster Coverage (bps)','Contigs','N50']].astype(int)
+    df_log_excluded_quast[['Sequence Length','Cluster Coverage (bps)','Contigs','N50']] = df_log_excluded_quast[['Sequence Length','Cluster Coverage (bps)','Contigs','N50']].fillna(-1).astype(int)
 
     # Rename and Drop columns
     df_log_excluded_quast = df_log_excluded_quast.rename(columns={'excluded_from_analysis':'Excluded from Parsnp\'s analysis'})