If you're on PrEP, plan on a check-in roughly every 3 months: an HIV test, screening for chlamydia, gonorrhea, and syphilis at the sites where you have sex, and a look at kidney function on the schedule your clinician sets. PrEP blocks HIV, not other STIs, so regular testing stays part of the deal.
Key figures
- From sex
- ~99%
- risk reduction, taken as prescribed
- From injection use
- ≥74%
- Forms
- pill or shot
- daily Truvada/Descovy or the Apretude injection
- Protects against
- HIV only
- not other STIs or pregnancy
| Item | Value |
|---|---|
| From sex | ~99%: risk reduction, taken as prescribed |
| From injection use | ≥74% |
| Forms | pill or shot: daily Truvada/Descovy or the Apretude injection |
| Protects against | HIV only: not other STIs or pregnancy |
Why being on PrEP means you still get tested
PrEP (pre-exposure prophylaxis) is medicine an HIV-negative person takes before possible exposure to keep HIV from taking hold. It's prevention, not treatment, and it works remarkably well: taken as prescribed, it cuts the risk of getting HIV from sex by about 99% and the risk from injection drug use by at least 74% CDC. That's the part most people know.
Here's the part that surprises people: PrEP only guards against HIV. It does nothing against chlamydia, gonorrhea, or syphilis, and it doesn't prevent pregnancy. So the same sex that PrEP makes safer for HIV can still pass a bacterial STI, which is exactly why monitoring stays on the calendar. A common mistake is treating PrEP like a morning-after pill; it isn't. PrEP works only when taken on an ongoing schedule, and if you've had a single recent exposure and aren't already on PrEP, the emergency option is PEP: taken after exposure, not before CDC PEP. The two aren't interchangeable.
Adherence is the whole game. In the iPrEx trial, participants with detectable drug levels saw greater than 90% protection against HIV iPrEx, which tells you the medicine has to actually be in your body to work. The regular visits aren't busywork, they confirm PrEP is doing its job and catch anything it can't prevent.
The quarterly cadence: HIV test and check-in about every 3 months
The backbone of PrEP monitoring is a visit roughly every 3 months. The most important piece is an HIV test. Confirming you're still HIV-negative matters because if someone has acquired HIV without knowing it, staying on a PrEP-only regimen can allow the virus to develop resistance, which limits future treatment options. Catching it early instead means moving straight to proper HIV care, and starting treatment promptly protects both your health and your partners; earlier hiv treatment can help prevention of onward transmission.
If you're on a long-acting option, the rhythm of visits follows the medicine. Injectable cabotegravir (Apretude) is given on a set injection schedule, and in 2025 the CDC added injectable lenacapavir as an option dosed every 6 months under the skin, updating the 2021 PrEP guideline based on two randomized controlled trials CDC MMWR, 2025. Even with a twice-a-year shot, HIV and STI monitoring still happens on the recommended intervals, the longer dosing gap doesn't stretch out your testing.
Kidney function monitoring
The daily oral pills, Truvada and Descovy, are processed in part by the kidneys, so clinicians check kidney function periodically while you're on them. Truvada is for people at risk through sex or injection drug use; Descovy is for those at risk through sex only, and it isn't approved for people assigned female at birth who are at risk through receptive vaginal sex. Your clinician orders a blood test to estimate how well your kidneys are filtering and repeats it on a schedule based on your age and baseline results. Injectable lenacapavir and cabotegravir (Apretude, for people at risk through sex who weigh at least 77 pounds) sidestep the daily oral exposure, which is one reason some people choose a shot, but they still come with their own monitoring and the same STI testing.
Bacterial STI screening: chlamydia, gonorrhea, and syphilis
Because PrEP leaves you exposed to bacterial STIs, screening for chlamydia, gonorrhea, and syphilis is built into PrEP care. Two details matter most. First, the timing: syphilis is checked with a blood test, and chlamydia and gonorrhea are tested on the recommended intervals while you're on PrEP. Second, and this gets missed, the testing has to match the sites where you actually have sex. A throat or rectal infection won't show up on a urine test, so if you have oral or anal sex, swabs from those sites are how you catch what a urine sample alone would miss. Tell your clinician honestly where you're having sex; it changes which tests you need.
Many of these infections cause no symptoms at all, which is the whole reason routine screening exists. Untreated, they don't stay quiet forever: chlamydia and gonorrhea can climb into the reproductive tract and cause pelvic inflammatory disease (infection of the uterus and tubes that can damage fertility) or epididymitis (inflammation of the tube behind the testicle), and untreated syphilis progresses in stages that can eventually harm the brain, nerves, and heart. Routine PrEP screening catches them while they're easy to cure.
What happens at each PrEP visit
- An HIV test to confirm you're still negative, this is the non-negotiable centerpiece.
- A check-in about how PrEP is going: are you taking it on schedule, any side effects, any new exposures or partners.
- STI screening for chlamydia, gonorrhea, and syphilis, with swabs from the throat or rectum if you have oral or anal sex.
- Periodic kidney function bloodwork if you're on a daily oral pill.
- A refill or your next injection, plus a quick review of whether your current PrEP option still fits your life.
In practice, starting PrEP means an HIV test up front and these recurring check-ins while you stay on it. Both clinics and telehealth services prescribe PrEP and order the labs, and patient-assistance programs exist to cover the cost, so price or a busy schedule shouldn't be the reason you skip monitoring. If your clinic doesn't bundle STI screening into your PrEP visits, you can get tested separately and bring the results along; you can also compare testing providers to find one that fits.
Why skipping monitoring is risky
Three things go wrong when the visits slide. You can carry an asymptomatic STI for months and unknowingly pass it on. An undiagnosed HIV infection treated with PrEP-only medicine can build drug resistance. And kidney changes on the oral pills can go unnoticed until they're harder to manage. Worldwide more than 2.5 million people received PrEP in 2022, yet PrEP, and the monitoring that goes with it, remains underused PrEP review. The check-ins are short. The consequences of missing them aren't.
PrEP monitoring at a glance
| What's checked | Roughly how often | Why |
|---|---|---|
| HIV test | About every 3 months | Confirm you're still negative and avoid resistance if status changed |
| Chlamydia & gonorrhea | On recommended intervals, at all exposure sites | PrEP doesn't prevent them; many cases have no symptoms |
| Syphilis (blood test) | On recommended intervals | Can be silent early, serious if untreated |
| Kidney function | Periodically on daily oral pills | Truvada/Descovy are cleared partly by the kidneys |
When to see a clinician
Beyond your scheduled visits, reach out sooner if you have a possible HIV exposure you're worried about, new genital, anal, or oral symptoms (discharge, sores, burning, a rash), or you've missed doses and aren't sure you're protected. If you've had a single high-risk exposure and you're not already on PrEP, that's a PEP situation: get care right away, because PEP is time-sensitive. Wondering how soon a test can detect something after sex? See when to test after exposure.
Keep exploring on EasySTD: which STD test you need, whether PrEP is right for you and Chlamydia testing.