diff --git a/src/svtk/svtk/pesr/pesr_test.py b/src/svtk/svtk/pesr/pesr_test.py
index a39581476..5668f9147 100644
--- a/src/svtk/svtk/pesr/pesr_test.py
+++ b/src/svtk/svtk/pesr/pesr_test.py
@@ -77,7 +77,7 @@ def normalize_counts(self, counts, target_cov=60):
         counts = pd.merge(counts, self.medians, on='sample', how='left')
         counts['norm_count'] = counts['count'] * \
             target_cov / counts['median_cov']
-        counts['count'] = counts['norm_count'].round()
+        counts['count'] = counts['norm_count'].astype(float).round()
         counts.drop(['norm_count', 'median_cov'], axis=1, inplace=True)
 
         return counts