The first 72 hours
Almost nothing about testing matters yet. Two things do, and both stop being options once the clock runs out.
Something happened, and now you are looking at your phone at two in the morning trying to work out how worried to be. Here is the useful version: the next three days are the only period where you can still change the outcome. After that, the situation is what it is and the rest is testing on a schedule.
So the question is not should I get tested. It is these two, in this order.
Testing before day 14 tells you almost nothing. Put the dates in something that will remind you, and stop refreshing.
The exposure, not the moment you started worrying about it. If there were several encounters over a weekend, PEP timing runs from the most recent one — but if the earliest is already outside the window, say so anyway. It changes what a clinician recommends.
What PEP actually involves
Twenty-eight days of antiretrovirals, the same class of drug used to treat HIV. It is not pleasant for everyone — nausea and fatigue are common in the first week — and it requires a baseline HIV test before starting and follow-up tests after. It is also extremely effective when started early, which is why the 72-hour ceiling is treated as hard rather than approximate.
You do not need to prove anything or explain the circumstances in detail to get it. What a clinician needs to know is the type of contact, roughly when, and whether the other person's status is known. "I don't know" is a complete answer to the last one and does not count against you.
If this is the second or third time you have needed PEP, that is the conversation to have on the way out: ongoing PrEP is the answer to a recurring situation, and repeat PEP courses are a signal to a clinician that it is time to switch.
Then what
Once the 72 hours have passed, the whole thing becomes a calendar problem. Two rounds of testing cover almost everything.
The detail behind those dates — which test type shortens which window, and why a fingerstick result at four weeks means less than a lab result at four weeks — is on its own page.
Questions people actually ask
It has been four days. Have I missed everything?
You have missed PEP and DoxyPEP, and that is genuinely worth knowing for next time. Nothing else has a deadline. Testing on the normal schedule from here is exactly what someone who took both would also be doing.
I have PEP left over from last time. Can I just start it?
Physically yes, and people do. The reason to go in anyway is the baseline HIV test — starting antiretrovirals on top of an infection that is already established, without knowing it, is the one scenario that causes real problems. Bring the leftover box with you; it speeds things up.
The condom broke and I am on PrEP. Anything to do?
For HIV, no — that is what PrEP is for, assuming you have been taking it correctly. Bacterial infections are not covered, so the day 14 test still applies. If you are on 2-1-1 rather than daily dosing, check that the encounter fell inside your covered window.
I do not know what happened. I was too out of it.
Then assume the highest-risk version and act on that. A clinician would rather see you inside 72 hours with an uncertain story than a week later with a confident one. If there is any chance the sex was not consensual, sexual health services can also connect you to support for that — you can raise it or not, and either is fine.
This page is general information about how prevention and testing work, not medical advice, and it cannot tell you what is right for your situation. Guidance differs between countries and changes over time. Anything specific to you is a conversation for a clinician or sexual health service. Candor is a personal record-keeping app; it does not diagnose, treat or prescribe.
Get Candor
Start the clock automatically
Log the encounter and Candor counts the windows for you — the 72-hour marks, then every test date after them.
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