Chlamydia is diagnosed with a nucleic acid amplification test (NAAT), a lab method that detects the bacterium's DNA. You give a first-catch urine sample or a self-collected swab (vaginal, rectal, or throat); no blood draw is needed. The test is most reliable about two weeks after exposure, and results usually arrive within a few days.
How chlamydia is tested: NAAT explained
Chlamydia is caused by the bacterium Chlamydia trachomatis, and most US genital infections come from serovars D–K CDC About Chlamydia. Because the organism lives inside cells and is hard to grow in a lab, the standard of care is the NAAT, which copies and detects the bacterium's genetic material rather than trying to culture it.
| Item | Reported cases |
|---|---|
| Chlamydia | 1,648,568 |
| Gonorrhea | 601,319 |
| Syphilis (P&S) | 53,007 |
NAAT is the recommended method for both genital and extragenital (rectal, throat) infection because it's far more sensitive than older tests CDC STI Treatment Guidelines, 2021. Chlamydia is often silent, so a test that misses low-level infection lets it spread and quietly cause damage. The NAAT picks up even small amounts of bacterial DNA, so a single accurate test usually settles the question.
What sample is taken: urine vs swab
The right sample depends on your anatomy and where you may have been exposed. Approved specimen types include first-catch urine, endocervical, vaginal, male urethral, rectal, and pharyngeal swabs. For most people the easiest accurate options are a urine cup or a self-collected vaginal swab. Both perform well and neither requires anything invasive.
- First-catch urine: You collect the first part of your stream in a cup. For best accuracy, don't urinate for about an hour beforehand. There's no urethral swab involved with the urine test, a common fear that keeps people away.
- Vaginal swab: A short, self-collected swab is as reliable as a clinician-collected one and is the preferred sample for women.
- Rectal and pharyngeal (throat) swabs: If you've had receptive anal or oral sex, a urine test alone can miss infection at those sites, so site-specific swabs are needed.
- Endocervical or male urethral swabs: Sometimes collected by a clinician during a pelvic or genital exam, though urine and self-swabs have largely replaced them for routine screening.
If you're testing for chlamydia, it's reasonable to test for gonorrhea at the same time. The two are collected the same way and frequently travel together. If you're weighing the differences, see chlamydia vs gonorrhea.
When to test after exposure: the window
The biggest mistake people make is testing the morning after a hookup. A NAAT detects bacterial DNA, and there needs to be enough of it to find, so a test taken too early can come back negative even when infection is taking hold. As a practical rule, the NAAT is most reliable about two weeks after exposure.
If symptoms appear at all, they usually show up within one to three weeks after exposure, though most people have none. A negative test taken a day or two after sex is falsely reassuring; if you tested very early, repeat it once you're past the window. For the full timing logic across STIs, see our guide on when to test after exposure. Men noticing discharge or burning can also read up on chlamydia symptoms in men.
Who should get screened
Screening recommendations are deliberately asymmetric because the serious complications, pelvic inflammatory disease and infertility, fall mainly on women. The US Preventive Services Task Force (Grade B, 2021) recommends screening all sexually active women 24 or younger, and women 25 and older who are at increased risk, including during pregnancy USPSTF, 2021. For men, the USPSTF issued an I-statement (insufficient evidence), which is a lack of strong data rather than a recommendation against testing.
The CDC adds guidance for higher-risk groups. Sexually active men who have sex with men should be screened at least annually at every site of exposure (urethra/urine, rectum, and throat) and every three to six months if at higher risk. Anyone diagnosed with chlamydia should also be offered HIV testing. The CDC's DoxyPEP guidance (2024) offers a single dose of doxycycline within 72 hours of sex to MSM and transgender women who've had a bacterial STI in the past year, which reduces chlamydia by more than 70 percent CDC DoxyPEP, 2024.
Getting tested: what the visit or at-home kit is like
Testing is quick. In a clinic you'll typically hand over a urine cup or use a self-swab in a private bathroom, with no needle and no exam required for a standard screen, and many labs text results within one to three days. Chlamydia is the most commonly reported bacterial STI in the US, with about 1.65 million reported cases in 2023, so clinics handle this constantly CDC AtlasPlus, 2023.
Cost rarely needs to be a barrier. Testing is free or low-cost at Planned Parenthood, local health departments, and Title X clinics, and it's often $0 with insurance. At-home NAAT kits, where you collect the sample and mail it to a lab, generally run about $50 to $150. You can compare options and order through our partner to get tested.
Reading your results
A positive NAAT means chlamydia DNA was detected, so you have an active infection and need treatment. A negative result means none was found, and you can trust it as long as you tested after the window and sampled every exposed site. If you tested too early or have ongoing symptoms, retest rather than relying on that negative.
After treatment, everyone should be retested about three months later. That follow-up catches reinfection, which is common because a partner often goes untreated, rather than checking whether the antibiotics worked. A test-of-cure isn't advised for non-pregnant people unless you couldn't finish the medication, your symptoms persist, or reinfection is suspected. Pregnant patients are the exception: they get a test-of-cure about four weeks after finishing treatment and a retest at three months.
After a positive: treatment and partners
Chlamydia is curable. The preferred treatment is a week of oral doxycycline twice daily; alternatives include a single-dose oral antibiotic or a different week-long pill course CDC Chlamydial Infections. The week-long course became first-line partly because it clears rectal infection far better: a randomized trial found 100% cure with doxycycline versus 74% with single-dose azithromycin Rectal CT RCT. Pregnant patients are treated with a single-dose regimen instead. Full details, including dosing, are on our chlamydia treatment page.
Partners from the prior 60 days need to be tested or treated, and you should avoid sex until a week after single-dose therapy or until your full pill course is done. Expedited partner therapy, where you take medication or a prescription to your partner, measurably cuts repeat infection and is allowed in most but not all US states, so verify local rules. The table below sums up the experience end to end.
| Step | What it involves | What to expect |
|---|---|---|
| Sample | First-catch urine or self-collected swab | No blood draw; private and quick |
| Timing | Most reliable ~2 weeks after exposure | Too early = unreliable negative |
| Results | NAAT detects bacterial DNA | Often texted in 1–3 days |
| If positive | Antibiotics; treat partners; abstain per instructions | Routine and curable |
| Follow-up | Retest ~3 months later | Catches reinfection, not cure |
When to see a clinician
See a clinician promptly if you have abnormal discharge, burning with urination, pelvic or testicular pain, bleeding between periods or after sex, or if a partner tells you they tested positive. Don't wait for symptoms, since most infections are silent, which is why screening exists. If a positive result comes back, treat it as routine: clinics manage it daily, the cure is straightforward, and the main jobs are finishing your medication, getting partners treated, and putting the three-month retest on your calendar.