It generally takes between 10 days and 12 weeks for HIV to be detected by a test, depending on the type of test used.
Detection Times by Test Type
- Nucleic Acid Tests (NAT) can detect HIV the earliest, usually within 10 to 33 days after exposure, by looking directly for the virus in the blood.
- Fourth-generation antigen/antibody tests detect both antibodies and the p24 antigen, typically identifying HIV infection within 18 to 45 days; these tests detect 99% of cases by 6 weeks.
- Third-generation antibody-only tests take longer, often requiring up to 60 days to reliably detect HIV.
- Rapid tests and self-tests, which mostly detect antibodies, have a window period of up to 90 days for accurate results.
Window Period Explanation
- The window period is the time between exposure to HIV and when the virus or the body's response to it can be detected by a test.
- During this period, an infected person may test negative despite being contagious.
- To be confident in an HIV-negative result, testing is generally recommended around 6 weeks with a fourth-generation test, with a follow-up test at 12 weeks for confirmation.
Summary of Typical Detection Periods
Test Type| Detection Window (after exposure)| Notes
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Nucleic Acid Test (NAT)| 10 to 33 days| Detects virus RNA, earliest detection
Fourth-generation test| 18 to 45 days| Detects antigen and antibodies
Third-generation antibody test| Up to 60 days| Detects antibodies only
Rapid/self-tests| Up to 90 days| Mostly antibody based, slower detection
Testing as soon as possible after suspected exposure and consulting healthcare professionals for appropriate follow-up testing is crucial for accurate diagnosis and early treatment options.
