General medical words
What Does False Positive Mean on a Test Result?
False Positive · say it: fawls POZ-ih-tivAlso written: false-positive result, false alarm, false negative
Short answer
A false positive is a test result that says something is present when it is actually not; a false negative is the opposite.
What it means
No medical test is perfect. Sometimes a test signals that a condition or substance is present when it really is not. That is a false positive. When a test misses something that is really there, that is a false negative.
False positives are especially common with screening tests, which are designed to catch as many possible cases as they can. This is why a positive screening result is usually followed by a more specific confirmatory test.
False results can be caused by many things, including the test's limits, timing, cross-reaction with similar substances, medicines, or handling of the sample.
Where you may see it
- Screening test results (cancer, pregnancy, drug and newborn screens)
- Infection and antibody tests
- Follow-up letters asking for repeat tests
📄 How it looks on a report
Screening result: Reactive. Confirmatory testing recommended.
🙅 What it does not mean
- A positive screening test is not a diagnosis; it means more testing is needed.
- Being asked for a repeat or confirmatory test does not mean the doctor expects bad news.
- A false positive does not mean the lab made a mistake; it is a known limitation of tests.
🗒️ Questions to ask your doctor
🧾 Reports where you will see “False Positive”
Paste or upload the report and every line of it is explained, with personal details removed first.
💊 Medicines whose labels mention “False Positive”
Plain-English explanations of each medicine, from its official FDA label.
- Cephalexin
a cephalosporin antibacterial medicine (an antibiotic that treats bacterial infections)
- Gabapentin
An antiepileptic (seizure) medicine. The label also describes it as a treatment for nerve pain after shingles.
🔗 Read more from trusted sources
- “False Positive” on MedlinePlus ↗
US National Library of Medicine
Seeing this word on your own report? Get every line of it explained, free.
Explain my report🧩 Related words
🔎 Look up another word
More words: general medical words
General information about a medical word, not advice about your own results. Ask the clinician who ordered the test what it means for you.