diff --git a/src/index.ts b/src/index.ts
index b50ede4..435f1da 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -788,7 +788,7 @@ export class ValidationService {
         }
 
         let fieldUID = this.getElementUID(field);
-        return this.summary[fieldUID] != null;
+        return this.summary[fieldUID] === undefined;
     }
 
     /**