Also, false negative.
1. Medicine/Medical. a.
a test result that is incorrect because the test failed to recognize an existing condition or finding.
a person who receives this test result.
any screening test result that failed to detect a person or thing being sought: Let's hope the new body scanner doesn't give us any false-negatives.
a person or thing that is missed by such a test: Retrain your spam filter if you’re getting too many false-negatives in your inbox.
pertaining to or being a false-negative.