It can be confusing and concerning when you test positive for chlamydia but your partner tests negative. Chlamydia is a common sexually transmitted infection that is caused by the bacteria Chlamydia trachomatis. It is spread through unprotected vaginal, anal, or oral sex with someone who has chlamydia. Here are some possible reasons you could have tested positive when your partner tested negative:
False negatives happen
No STI test is 100% accurate. There is always a chance of a false negative result, meaning the test says your partner is negative but they are actually positive. The specificity of nucleic acid amplification tests (NAATs) for chlamydia is over 99%, but false negatives still occur about 1-3% of the time.
Reasons your partner could have falsely tested negative include:
- They were tested too soon after possible exposure before their infection could be detected
- They did not provide an adequate urine or swab sample for testing
- Lab errors or mishandling of their sample
- Their infection was in a part of the body not tested – only genital samples are usually tested
If you have tested positive but your partner’s negative test does not make sense, it is a good idea for them to get re-tested to confirm. They should also get treated along with you to prevent passing the infection back and forth.
You had the infection first
It is possible that you contracted chlamydia from a prior partner and have had it for a while. Since chlamydia often causes no symptoms, you may have had it without knowing. If your current partner has truly tested negative, it means they did not get the infection from you (yet).
You may have had chlamydia for months or longer before your current partner if:
- Your last STI screening was negative for chlamydia
- You have not had any new partners between that last screening and your current relationship
- Your current partner has tested negative
In this situation, make sure your partner gets treated as well to prevent infecting them. You should also notify any partners from the last few months so they can get tested.
Your partner acquired it very recently
Chlamydia can sometimes evade detection on tests for the first few weeks after infection. If your partner engaged in unprotected sex in the past 2-3 weeks, they may have just become infected but are not testing positive yet.
Some key indicators your partner recently acquired chlamydia include:
- You have had unprotected sex with your partner for several months with no issues
- Your partner admits to a recent encounter that could have exposed them
- Their test was within 14-21 days of this possible exposure
If this is the case, your partner should get retested 2-3 weeks later to check if the infection now shows up. It is also wise for them to get treated now since they were exposed.
You re-acquired it from your partner
Sometimes couples can pass chlamydia back and forth if they start having unprotected sex again too soon after treatment. If one partner still has the infection, they can re-infect the other.
Consider this possibility if:
- You and your partner were both treated for chlamydia recently
- You had unprotected sex again before finishing treatment or testing negative again
- Now you have tested positive but your partner is currently negative
To break this cycle, you and your partner should abstain from sex or use protection for 7 days after finishing treatment. Get retested after 3 weeks to confirm you are cured.
You have an untreated co-infection
If you have a co-infection with another STI like gonorrhea, that could also be causing your positive chlamydia test result. Gonorrhea and chlamydia often occur together.
Consider this if:
- You or your partner have had any unusual discharge or burning during urination
- You have not been tested yet for gonorrhea or other STIs
Ask your doctor to test you and your partner for gonorrhea or trichomoniasis to see if co-infection is a possibility. Get treated for any infections found.
Condoms are not 100% protective
While condoms significantly reduce the risk of STIs, they do not completely eliminate it. The bacteria that causes chlamydia can still be transmitted through skin-to-skin contact of infected areas not covered by the condom.
You may have gotten chlamydia despite using condoms if:
- You used condoms each time you had sex with your partner
- A condom slipped or broke during sex
- Your partner’s infected skin touched your genitals or vice versa
To reduce this risk, make sure condoms are used correctly every time you have sex. Limit skin-to-skin contact when changing positions or using hands/mouths on each other’s genitals after intercourse.
Non-sexual transmission is possible but rare
While chlamydia is almost always spread sexually, there are some rare instances where non-sexual transmission can occur:
- Mother to newborn: A pregnant woman can pass chlamydia to her baby during childbirth if she has an untreated infection.
- Shared sex toys: If sex toys are shared between partners without disinfecting between uses, bacteria could be transmitted on the toy’s surface.
- Laboratory exposure: There are documented cases of lab technicians acquiring chlamydia after exposure to infected clinical specimens.
These types of transmission are very uncommon. If they do not apply to your situation, then you likely acquired chlamydia through sex with someone who had it.
Conclusion
While it can seem confusing when you test positive but your partner doesn’t, there are reasonable explanations for how this could occur. The most likely scenarios are a false negative for your partner, you had it before this relationship, or you re-acquired it from your partner after treatment. To address the situation:
- Have your partner get retested to confirm their negative result
- Make sure you both complete treatment before having unprotected sex again
- Get retested 3 weeks after treatment to ensure you are cured
- Notify any recent partners from the past 2-3 months to get tested
If you still have questions after considering these possibilities, have an open discussion with your partner and together review each of your recent sexual histories. Your doctor can also help interpret test results and recommend next steps. With the right treatment and prevention methods, you and your partner can stay healthy moving forward.