HIV test accuracy
Accuracy is not one number. A test has sensitivity (how well it finds true infections) and specificity (how well it correctly clears people who are not infected), and both are measured under specific conditions.
Diagnik Health Library · Updated
The two numbers behind accuracy
Manufacturer performance figures apply to the sample type the test was authorized for and to samples taken outside the window period. Diagnik quotes performance figures only from the manufacturer documentation for the specific test.
- Sensitivity: the proportion of true positives the test detects. Low sensitivity means missed infections.
- Specificity: the proportion of true negatives correctly identified. Low specificity means more false alarms.
The two things that most often go wrong at home
- Testing too early. Inside the window period, an antibody test can be non-reactive despite infection.
- Not following the instructions. Reading the result too early or after the stated window, or swabbing incorrectly, invalidates it.
False positives and false negatives
A false positive is why any reactive screening result is preliminary and confirmed clinically. A false negative is usually a timing problem, which is why retesting after the window period matters.
Tests mentioned in this guide
Frequently asked questions
- Can an at-home HIV test be wrong?
- Yes, in both directions. Testing inside the window period can produce a false negative, and a small number of reactive results are not true infections — which is why confirmatory testing exists.
- Does reading the result late change it?
- Yes. Reading outside the stated time window makes the result unreliable. The OraQuick In-Home HIV Test is read between 20 and 40 minutes.
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Sources
Educational information only, not a medical diagnosis or treatment advice. Screening results always need confirmation by a clinician.
This guide is general health information about screening tests. It is not a diagnosis and does not replace care from a clinician. See our medical disclaimer.