Chlamydia is diagnosed with a simple lab test that detects the bacteria’s genetic material in a urine sample or swab. Most people get results within a day, and the test is highly accurate, with sensitivity above 90% and specificity at 99% or higher. Because chlamydia often causes no symptoms, testing is the only reliable way to know if you have it.
The Standard Test
The go-to method is called a nucleic acid amplification test, or NAAT. It works by taking a tiny amount of genetic material from the chlamydia bacteria and copying it millions of times until there’s enough to detect. This makes NAATs extremely sensitive: they can pick up an infection even when very few bacteria are present. Older methods like bacterial culture miss far more cases.
In practice, chlamydia and gonorrhea are almost always tested together using a single combination assay. The two infections share similar risk factors and can occur at the same time, so dual testing is standard. You’ll typically get results for both from one sample.
What the Test Involves
For women, the recommended sample is a vaginal swab, which you can usually collect yourself in a bathroom at the clinic. A vaginal swab catches about 94% of chlamydia infections, compared to roughly 87% for a urine sample. That gap means urine testing may miss up to 10% of infections that a swab would catch. Despite this, urine remains the most commonly used specimen among women because it’s convenient and noninvasive.
For men, the standard specimen is a first-catch urine sample (the first part of your urine stream). Urethral swabs are an alternative but rarely necessary since urine performs well for detecting urethral infections in men.
If you’ve had oral or anal sex, your provider may recommend swabs from the throat or rectum. A urine test only checks the urinary tract, so infections at other sites would go undetected without site-specific testing. Self-collected rectal and throat swabs perform comparably to clinician-collected ones, and several FDA-cleared assays now support both options.
When to Get Tested After Exposure
Testing too soon after a potential exposure can produce a false negative. Chlamydia needs time to establish enough of a bacterial presence to be detectable. Most infections will show up on a NAAT after one week. Waiting two weeks catches nearly all cases. If you test earlier than that and get a negative result but still have concerns, retesting after the two-week window gives you a more reliable answer.
Who Should Be Screened Routinely
The U.S. Preventive Services Task Force recommends annual chlamydia screening for all sexually active women aged 24 and younger. Women 25 and older should be screened if they have risk factors such as a new sex partner, more than one partner, a partner with an STI, inconsistent condom use outside a mutually monogamous relationship, or a previous STI.
For men who have sex with men, the CDC recommends screening for rectal chlamydia and gonorrhea at least once a year, and every three months for those at higher risk or taking HIV pre-exposure prophylaxis. Routine screening for heterosexual men in low-prevalence settings isn’t currently recommended, though it may be considered in higher-prevalence environments like STI clinics or correctional facilities.
There’s no firm rule on how often to rescreen after a negative result. The general guidance is to test again whenever your sexual history includes new or ongoing risk factors since your last negative test.
Extragenital Testing
Chlamydia can infect the rectum and, less commonly, the throat. These infections often produce no symptoms and won’t be caught by a standard urine test. Rectal screening is recommended for men who have sex with men based on the annual or quarterly schedule above, and for cisgender women based on sexual behavior and shared decision-making with a provider. Throat screening for chlamydia specifically is generally not recommended for women, though throat testing for gonorrhea is.
NAAT testing at rectal sites has a sensitivity of about 93% for chlamydia, far outperforming older culture methods that detected only 27% of rectal infections. Specificity remains above 99% regardless of the body site tested.
At-Home Testing
The FDA has authorized the first fully at-home test for chlamydia, gonorrhea, and trichomoniasis: the Visby Medical Women’s Sexual Health Test. It’s available without a prescription and uses a self-collected vaginal swab with a small powered testing device that sends results to a smartphone app. In clinical validation, the test correctly identified 97.2% of positive chlamydia samples and 98.8% of negative ones.
This option is currently designed for vaginal specimens only, so it doesn’t replace clinic-based testing if you need rectal or throat screening. It does, however, remove several barriers to testing, particularly for people who avoid clinic visits due to stigma, cost concerns, or scheduling difficulties.
Getting Your Results
Lab-processed NAAT results are typically ready within one day. Some clinics offer rapid point-of-care tests that return results in 90 minutes or less, though these are less widely available. The at-home Visby test also provides same-session results.
A positive result means the bacteria were detected and you’ll need antibiotic treatment. Chlamydia is curable with a short course of antibiotics, and retesting three months after treatment is recommended to check for reinfection. A negative result is highly reliable if the test was taken at least two weeks after your last potential exposure, given how accurately NAATs rule out infection.