After STD treatment, timing depends on what you're checking. A true test of cure — confirming the infection is gone — is only routine for a few infections and is done weeks after you finish meds. Separately, most people treated for chlamydia or gonorrhea should retest about three months later to catch reinfection, not treatment failure.
| Item | Days after exposure |
|---|---|
| Chlamydia / gonorrhea (NAAT) | ~14 |
| HIV — NAT | 10–33 |
| HIV — antigen/antibody | 18–45 |
| HIV — rapid antibody | 23–90 |
Test of cure vs. reinfection retest: two different things
These two ideas get blended together constantly, and the confusion leads people to test at the wrong time. A test of cure asks one question: did the treatment clear the infection? A reinfection retest asks a different one: have you picked it up again from an untreated or new partner? They happen on different schedules for different reasons.
For most uncomplicated bacterial STIs treated with the right antibiotic, the cure rate is high enough that a routine test of cure isn't recommended — testing too soon after treatment can even turn up dead bacterial genetic material on a sensitive test and read positive when you're actually cured. That's why the more important follow-up for many people is the three-month retest for reinfection. See our deeper guide on chlamydia reinfection for why this window catches so many repeat cases — chlamydia reinfection.
How the test works (sample and method)
The sample depends on the infection. Chlamydia, gonorrhea, and trichomoniasis are detected with a NAAT (nucleic acid amplification test) run on a urine cup or a self-collected swab. HIV, syphilis, and hepatitis are blood tests done from a quick draw CDC, HIV Testing.
NAATs are the most sensitive method for chlamydia and gonorrhea, which is why they're the recommended test — modern NAATs are highly accurate, with specificity around 99% USPSTF screening. The flip side of that sensitivity matters after treatment: a NAAT can pick up leftover genetic fragments from killed bacteria, so a positive run too soon doesn't necessarily mean live infection.
In practice, testing is fast. A urine cup or self-swab takes minutes; the blood draw for a syphilis test or HIV is a single quick stick — syphilis test. Results usually come back in a day to a few days.
When to retest, by infection
Here's how the timing breaks down across the common infections. The window period — the gap between exposure and when a test can detect anything — applies after a new exposure, not just at first diagnosis, which is why a fresh exposure between treatment and retest can matter.
Chlamydia and gonorrhea
Chlamydia and gonorrhea don't need a routine test of cure after standard treatment in most uncomplicated cases CDC Chlamydia Guidelines. The recommended follow-up is a retest about three months after treatment to catch reinfection, because the most common reason these come back is a partner who wasn't treated. A NAAT becomes reliable again about two weeks after any new exposure, so if you test too soon after a recent contact, repeat it later.
Test of cure is reserved for specific situations — for example, during pregnancy, when symptoms persist, or when there's concern the medication wasn't taken correctly. In those cases your clinician will tell you the timing and method.
Trichomoniasis
Trichomoniasis is also a NAAT-detectable infection, and reinfection is common when a partner goes untreated. A retest in the months after treatment is reasonable rather than an immediate recheck — the goal again is catching a repeat infection, not second-guessing a cure.
Syphilis
Syphilis is different because the blood test that tracks it actually measures your response to treatment over time rather than presence or absence on a single day. Follow-up blood tests at intervals after treatment let a clinician confirm the numbers are falling the way they should — that trend is the cure signal CDC Syphilis Lab, 2024. Don't expect a one-and-done recheck; syphilis follow-up is a series of draws.
HIV and hepatitis
HIV isn't curable, so there's no test of cure — monitoring is ongoing and managed differently. If you were tested around a possible exposure rather than treated, the window matters: a nucleic acid test (NAT) can detect HIV about 10–33 days after exposure, an antigen/antibody lab test about 18–45 days, and a rapid antibody test about 23–90 days. A too-early negative should be repeated once the window has passed.
| Infection | Routine test of cure? | Reinfection retest |
|---|---|---|
| Chlamydia | No (most uncomplicated cases) | About 3 months after treatment |
| Gonorrhea | No (most uncomplicated cases) | About 3 months after treatment |
| Trichomoniasis | No | Months after treatment |
| Syphilis | Yes — follow-up blood tests track the response | Per clinician schedule |
| HIV | Not applicable — ongoing care | Not applicable |
When to test after a new exposure
Many STIs cause no symptoms, so how you feel doesn't tell you your status — testing does. If you have a new or possible exposure between treatment and your scheduled retest, that resets the window-period clock for that infection. Testing before the window closes is the main cause of a false negative: the test isn't broken, the infection just isn't detectable yet. For the full breakdown by infection, see when to test after exposure — when to test after exposure.
Where to get tested and what it costs
Retesting is widely available and often free or low-cost. You can go to a doctor's office, a health department, Planned Parenthood, or a Title X family-planning clinic, and at-home and self-collection kits exist for the urine/swab infections HRSA Find a Health Center.
You're rarely far from affordable care: the US has roughly 16,000 federally-funded community health centers and about 4,200 Title X clinics, plus tens of thousands of other public STI clinics — most offering free or income-based sliding-scale pricing. If you're using an at-home kit, mind the window period so you collect at the right time. You can get tested through several routes — get tested — and it helps to compare testing providers for cost, turnaround, and which infections each kit covers.
Reading your results and how accurate they are
A negative NAAT taken after the window has closed is reliable. A positive on a too-early retest after bacterial treatment can reflect residual genetic material rather than live infection — one reason clinicians don't rush a recheck right after treatment.
HIV and syphilis use a two-step process to guard against false positives: an initial screening test followed by a different confirmatory test, and the result isn't final until the confirmatory step agrees. A reactive rapid HIV test is preliminary — it must be confirmed with a follow-up lab test before it counts as a diagnosis.
If a retest is positive
A positive retest usually means reinfection from an untreated partner, not failed treatment — and it's treatable. Don't wait it out; get evaluated and treated, and make sure partners are treated too so you're not bounced back and forth. Walk through the next steps with our treatment guide.
When to see a clinician
- You finished treatment but symptoms persist or come back — that warrants an in-person evaluation, not just a repeat home test.
- You were treated during pregnancy — test-of-cure timing is specific and should be clinician-directed.
- You have a new exposure between treatment and your scheduled retest — tell your clinician so timing can be adjusted to the window period.
- A screening test is reactive or positive — confirmatory testing and treatment should happen promptly.
- You're unsure whether a partner was treated — that's the most common driver of reinfection and worth raising.