Chlamydia is a common sexually transmitted infection (STI) caused by the bacteria Chlamydia trachomatis. It often has no symptoms, so many people don’t realize they have it. This allows chlamydia to spread easily between sexual partners. Thankfully, chlamydia is curable with antibiotics. But to get treated, you first need to get tested. So how long after exposure will chlamydia show up on a test?
How Soon Do Chlamydia Symptoms Appear?
Many people wonder if chlamydia symptoms will show up right away. The incubation period for chlamydia is 1-3 weeks after exposure. This means symptoms can take up to 21 days to develop after catching chlamydia from a sexual partner. However, about 70-75% of women and 50% of men with chlamydia never experience any symptoms. When symptoms do occur, they may include:
Women
– Vaginal discharge
– Burning during urination
– Lower abdominal pain
– Bleeding between periods
Men
– Discharge from the penis
– Burning during urination
– Testicular pain
Without treatment, chlamydia can lead to long-term health problems like pelvic inflammatory disease, infertility, and ectopic pregnancy in women. In men, untreated chlamydia can cause epididymitis (inflammation of the epididymis, a tube that stores sperm).
Since chlamydia often has no symptoms initially, don’t wait until symptoms show up to get tested. The only way to know if you have chlamydia is through laboratory testing.
When Will Chlamydia Show Up on a Test?
There are a few different tests that can diagnose chlamydia. The most common options are:
– Nucleic acid amplification test (NAAT) – Looks for chlamydia DNA in urine or a swab sample
– Culture – Tries to grow chlamydia bacteria from a swab sample
Most chlamydia tests use either urine or a swab taken from the cervix or urethra. NAAT urine tests are common because they are non-invasive. However, cervical/urethral swabs tend to be more accurate.
How Soon After Exposure Can Chlamydia Be Detected?
Chlamydia becomes detectable by NAAT tests as soon as 2-5 days after exposure. But false negatives are more likely this soon after acquiring chlamydia. The bacteria may not have replicated enough to be picked up by the test yet.
After 7 days, NAAT tests for chlamydia are about 95% accurate. False negatives are unlikely at this point.
Here is a breakdown of when chlamydia becomes detectable after exposure:
| Days After Exposure | Chlamydia Detectable? |
|---|---|
| 1-2 days | Rarely |
| 3-5 days | Sometimes |
| 7-14 days | Almost always |
| 14-21 days | Always |
As you can see, NAAT urine or swab tests will successfully pick up chlamydia in most people by 7 days after exposure. But waiting the full 14-21 days after sex provides the most accurate test results.
What About Culture Tests?
Chlamydia culture tests take longer to become positive after infection. Cultures are less sensitive and may take up to 14 days or more to grow detectable levels of bacteria. NAATs that look for DNA are preferable to culture tests for rapid diagnosis.
Should I Get Tested for Chlamydia After 7 Days?
Health experts recommend re-testing for chlamydia 7-14 days after having unprotected sex with a new partner. Here’s why testing at one week is important:
You May Have Just Acquired Chlamydia
If your sexual partner is infected with chlamydia, you have a high chance of catching it after unprotected sex. About 75% of women and 50% of men get chlamydia after exposure from an infected partner.
It can take up to a week for the infection to become detectable on tests. Getting tested 7 days after a sexual encounter allows enough time for any newly acquired chlamydia to be picked up.
A Negative Test May Be a False Negative
No test is 100% perfect. While NAAT tests for chlamydia are highly accurate by one week, false negatives are still possible this early. Getting re-tested after 7-14 days reduces the chances of a false negative result.
You May Have Had Chlamydia Before
If you’ve tested positive for chlamydia in the past, you’ll want to get re-tested about a week after each new partner to check for re-infection. Failing to promptly re-test can lead to chlamydia spreading and causing complications.
Prompt Treatment Prevents Spread and Complications
The sooner you can detect and treat chlamydia, the better. Getting tested at 7 days allows for quick treatment if positive. This prevents transmission to future partners. It also reduces the risk of serious health problems in both women and men.
Interpreting Test Results
Wondering how to understand your chlamydia test result if you get tested at 7 days? Here are the possible outcomes:
Negative Result
A negative chlamydia test result 7 days after sex is reassuring. However, you could consider re-testing in another 7 days to check for any recently acquired infection. Use condoms until getting the second test.
Positive Result
If your chlamydia test is positive at 7 days, you likely just acquired a new infection from a partner. Get treated promptly to avoid complications. Make sure your sexual partners from the past 2 months get treated too.
Inconclusive Result
Rarely, technical issues can cause an inconclusive result. You should repeat the test with a new sample. Make sure to abstain from sex until you get a definitive negative or positive result. An inconclusive result is not informative.
Treatment for Chlamydia
If you test positive for chlamydia, antibiotics will cure the infection. Some treatment options include:
– Azithromycin – Single 1 gram oral dose
– Doxycycline – 100 mg twice daily for 7 days
Take all medication as prescribed, even if symptoms resolve quickly. You should abstain from sex for 7 days after starting antibiotics. Make sure your partner(s) get treated too. Retest in 3 months to check for re-infection.
Treating Partners
When you get diagnosed with chlamydia, any partners from the past 2-3 months need treatment too. This prevents ping-ponging the infection back and forth. Partners should get tested 3-4 weeks after completing antibiotics.
How to Prevent Chlamydia
Using condoms consistently and correctly helps prevent STIs like chlamydia. But condoms aren’t 100% foolproof. Getting regularly screened is important, even if you use protection.
The CDC recommends sexually active women under 25 get tested annually for chlamydia if they are not at increased risk. Women over 25 and men who have sex with women only need screening if at increased risk. Risk factors include:
– Multiple sexual partners
– New sexual partner in the past year
– Inconsistent condom use
– History of past STIs
– Exchanging sex for money/drugs
More Tips for Prevention
Here are some other tips to avoid getting chlamydia:
– Get annual STI exams if sexually active
– Ask partners to get tested before unprotected sex
– Limit sexual partners and avoid overlapping partners
– Use dental dams/condoms for oral sex
– Never douche, as this spreads STIs into the upper reproductive tract
By combining screening, condoms, and communicating with partners, you can greatly reduce your chlamydia risk.
The Bottom Line
Chlamydia may not produce symptoms initially, but can still be transmitted during that time. NAAT urine and swab tests for chlamydia are accurate by one week after exposure. If you have unprotected sex with a potentially infected partner, get tested after 7 days to allow detection of any new infection.
Prompt treatment prevents spreading chlamydia further and avoids complications like pelvic inflammatory disease. Retest in 3 months to check you haven’t been re-infected by an untreated partner. Practicing safer sex by using condoms and getting regular STI checks is key to reduce chlamydia risk.
References
1. Workowski KA, Bolan GA. Sexually transmitted diseases treatment guidelines, 2015. MMWR Recomm Rep. 2015;64(RR-03):1–137.
2. Centers for Disease Control and Prevention. Chlamydia – CDC Fact Sheet. Accessed January 12, 2022. https://www.cdc.gov/std/chlamydia/stdfact-chlamydia.htm
3. Eccles JM, Francis J, Abouzeid M, et al. Chlamydia trachomatis (Ct) infection tests: new technology searches for new cases. Diagnostics (Basel). 2019;9(3):102. Published 2019 Aug 7. doi:10.3390/diagnostics9030102
4. Schachter J, Moncada J, Liska S, Shayevich C, Klausner JD. Nucleic acid amplification tests in the diagnosis of chlamydial and gonococcal infections of the oropharynx and rectum in men who have sex with men. Sex Transm Dis. 2008;35(7):637–642. doi:10.1097/OLQ.0b013e31817bdd7e