diff --git a/src/app/features/genes/components/gene-comparison-tool/gene-comparison-tool.component.spec.ts b/src/app/features/genes/components/gene-comparison-tool/gene-comparison-tool.component.spec.ts
index ff31aab3..bc3b7f8f 100644
--- a/src/app/features/genes/components/gene-comparison-tool/gene-comparison-tool.component.spec.ts
+++ b/src/app/features/genes/components/gene-comparison-tool/gene-comparison-tool.component.spec.ts
@@ -530,7 +530,8 @@ describe('Component: GeneComparisonToolComponent', () => {
 
     it('should set circle size to zero for null pValues', () => {
       // null values should result in a circle size of zero pixels
-      const result = component.getCircleSize(null);
+      const pValue = null;
+      const result = component.getCircleSize(pValue);
       expect(result).toBe(0);
     });