Possible HIV Exposure: PEP Within 72 Hours
Medically reviewed by our MD Laboratory Director (a role required by CLIA; the director's name is on file in the CMS CLIA database, #45D2048957, and can be verified independently) · Editorial policy
72 hours. PEP started sooner works better. Do not wait for a test result to act.CLIA #45D2048957 · CAP #8722734 · Same-day results · Walk-ins welcome
Two things, in this order. First: seek care for post-exposure prophylaxis (PEP) immediately — CDC states PEP must be started within 72 hours of exposure, and effectiveness falls the longer you wait. Second: get a baseline test. A test taken today cannot tell you whether last night infected you — it establishes where you started.
Not sure what you need? Text us and we will set it up.
📱 Text (713) 832-8892 📞 Call (713) 266-0808
📱 Text (713) 832-8892 📞 Call (713) 266-0808
3707 Westcenter Dr Suite 100, Houston, TX 77042 · Walk-ins welcome
Why the test is not the emergency
| Hours since exposure | Priority |
|---|---|
| 0–72 hours | PEP evaluation — urgent. Baseline testing alongside it |
| After 72 hours | PEP is no longer indicated. Testing per the window period becomes the plan |
| 18–45 days | 4th-generation antigen/antibody test becomes reliable |
| 3 months | Definitive answer |
A negative HIV test the morning after an exposure is not reassurance. It is a baseline. The exposure you are worried about could not possibly be detectable yet.
What counts as an exposure worth acting on
Condomless sex with a partner of unknown or positive status, a broken condom, a needle-stick or shared injection equipment, or sexual assault. If you are unsure whether it qualifies, that uncertainty is itself a reason to be evaluated today rather than to search the internet at 3 AM.
A sexual exposure can also pass on chlamydia, gonorrhea, trichomonas or syphilis, and all four are among the STD tests we run in Houston.
We name drugs, never doses. Treatment statements follow CDC guidance; dose and duration are decided by a licensed physician who has your result and your history.
Same day, start to finish. Sample by 1:00 PM → results at 5:00 PM → if treatment is clinically appropriate, a licensed physician in our partner network sees you between 5:00 and 6:00 PM, a few minutes away. That window is reserved for patients tested here, and your slot is held the moment we take your sample — the slot is held, not hunted. On your own, a same-day appointment is nearly impossible; at an urgent care, you wait in the queue. STAT: ~2 hours, sample in by 3:00 PM.
FAQ
- Where do I get PEP?
- An emergency department, an urgent care, or a physician can start it. Do not delay this while arranging a test — the 72-hour clock is running.
- Should I still test here?
- Yes — a baseline today, then follow the window-period timeline. We will map the dates out for you.
- What about other infections from the same exposure?
- Test for chlamydia, gonorrhea, trichomonas and syphilis at the appropriate intervals. Sites matter — see the site guide.
- Is PEP the same as PrEP?
- No. PEP is emergency treatment after an exposure. PrEP is ongoing prevention before one. Ask a physician about both.
Not sure what you need? Text us and we will set it up.
📱 Text (713) 832-8892 📞 Call (713) 266-0808
📱 Text (713) 832-8892 📞 Call (713) 266-0808
3707 Westcenter Dr Suite 100, Houston, TX 77042 · Walk-ins welcome
References
- CDC — Post-Exposure Prophylaxis (PEP)
- CDC — HIV Laboratory Tests and Window Periods
- CDC — STI Treatment Guidelines, 2021
- Our CLIA #45D2048957 and CAP #8722734 credentials — verify them yourself
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