diff --git a/README.md b/README.md
index 59abda7..bb8dd27 100644
--- a/README.md
+++ b/README.md
@@ -11,7 +11,7 @@ This app should be executed stand-alone or as part of a DNAnexus workflow for a
 The app requires a VCF file (.vcf) containing variants to be evaluated and a bed file defining the regions within which variants in the vcf should be evaluated.
 
 ## What does this app output?
-The app outputs one tab delimited file `[vcf_prefix].vcf.qc`, where `vcf_prefix` is the vcf filename without extension:
+The app outputs one tab delimited file `[vcf_prefix].vcf.QC`, where `vcf_prefix` is the vcf filename without extension:
 
 * sample id
 * mean het ratio (mean AAF of het variants)
diff --git a/src/vcf_qc.py b/src/vcf_qc.py
index d63b52b..c94f009 100644
--- a/src/vcf_qc.py
+++ b/src/vcf_qc.py
@@ -300,7 +300,7 @@ def main(vcf_file, bed_file):
     het_hom_counts = get_het_hom_counts(vcf=tmp_vcf)
     ratios = calculate_ratios(counts=het_hom_counts)
 
-    outfile = f"{re.sub(r'.vcf(.gz)?$', '', vcf_file)}.vcf.qc"
+    outfile = f"{re.sub(r'.vcf(.gz)?$', '', vcf_file)}.vcf.QC"
 
     if os.path.exists("/home/dnanexus"):
         write_output_file(outfile=outfile, ratios=ratios)