Quick answer
If you may have been exposed to HIV, test as soon as possible and ask a qualified health worker when to retest. CDC explains that no HIV test can detect HIV immediately after exposure.
If exposure was recent, ask a health worker urgently about PEP because it must be started quickly after possible exposure.
Why window period matters
A negative result too early may not be final. Different tests detect antibodies, antigen/antibody, or viral material at different times. A clinic can explain which test you received and whether retesting is needed.
What to do after possible exposure
- Do not panic, but do not delay care.
- Visit a qualified health facility or HIV testing service.
- Ask about PEP if exposure was recent.
- Use condoms and avoid exposing others while awaiting clarity.
- Follow the retesting advice given by the health worker.
Related: Blood group and genotype, Typhoid vs malaria.