Can you have chlamydia with a negative test result?

A chlamydia infection can be present even if your test result is negative. Possible reasons include testing too early, inadequate sample collection, or a low bacterial load. In such cases, repeat testing is recommended. Being informed about a possible chlamydia infection is crucial, as untreated infections can lead to infertility, ectopic pregnancies, and chronic pain. There is also a risk of unknowingly transmitting the infection to sexual partners. In this article, we take a closer look at the reasons for a false-negative test result, what you can do if you suspect you are infected, and how you can prevent chlamydia.

Table of contents

• What is a chlamydia infection?
• Can you have chlamydia without symptoms?
• Can you have chlamydia and still test negative?
• Avoiding early testing: When is the best time to test?
• How can I prevent chlamydia?
• Summary

What is a chlamydia infection?

A chlamydia infection is a sexually transmitted infection caused by the bacterium Chlamydia trachomatis. It is primarily transmitted through unprotected vaginal, anal, or oral sex but can also be spread through infected bodily fluids and shared sex toys. During childbirth, the infection can also be passed from the mother to the newborn. However, direct skin contact alone does not lead to infection (Cleveland Clinic, 2023).

Can you have chlamydia without symptoms?

Chlamydia infections often occur without symptoms. Around 70% of infected women and 50% of infected men show no signs of infection, making it difficult to detect (NHS, 2024). If symptoms are present, women may experience unusual discharge, burning during urination, and lower abdominal pain. In men, symptoms can include discharge from the urethra, pain during urination, and testicular discomfort. If left untreated, the infection can lead to serious complications such as infertility or chronic pain (WHO, 2023).

Can you have chlamydia and still test negative?

Yes, it is possible to have chlamydia and still receive a negative test result. Reasons for this may include:

• Testing too early: A test performed too soon may return a negative result because the bacteria are not yet present in sufficient quantity to be detected. This can give the false impression that no infection is present, even though the bacteria may still become detectable later and could be transmitted to others.
• Inadequate or incorrect sample collection: This can result in a false-negative test because not enough infected tissue or bodily fluid is collected. Without enough bacterial material in the sample, the test cannot reliably detect the infection, even if one is present.
• Laboratory error: While laboratories are subject to strict quality controls, laboratory errors that lead to false-negative test results are rare. However, mistakes can occasionally occur if samples are mishandled, stored, or transported incorrectly, causing the infection to go undetected despite being present.
  

Source: Mayo Clinic, 2023

Avoiding early testing: When is the best time to test?

The best time to test is approximately 1 to 3 weeks after a potential exposure, as this is when a test can reliably detect an infection. This period is known as the diagnostic window – the time between infection and the point when it becomes detectable, once the pathogen has multiplied sufficiently. Testing too early, before enough bacteria are present in the body, may lead to a false-negative result. In this case, a repeat test should be considered (Cleveland Clinic, 2023).

When should you get retested?

Retesting for chlamydia is recommended in the following situations:

• 3 to 6 months after treatment to rule out reinfection
• About 1 to 3 weeks after unprotected sex or potential exposure
• If you experience symptoms such as discharge, pain during urination, or abdominal pain
• After a negative test result if infection is still suspected
• At the beginning of a new sexual relationship

Source: CDC, 2024

What should I do if I still have symptoms but tested negative for chlamydia?

If you continue to have symptoms despite a negative test result, it is advisable to consult a doctor. The doctor may recommend a PCR test (polymerase chain reaction), which is more accurate than standard tests. Testing for other sexually transmitted infections (STIs) may also be appropriate. Gonorrhoea, another bacterial STI, can cause symptoms similar to chlamydia, including discharge and pain during urination. Until a clear diagnosis is made and a possible infection is ruled out or treated, unprotected sex should be avoided to prevent transmission. You should also inform your sexual partners so they can be tested and treated early if necessary (NHS, 2024). 

Want to check in on your sexual health?

Homed-IQ offers the option to test yourself at home for various sexually transmitted infections (STIs). In addition to the chlamydia test, you can also take a combined chlamydia and gonorrhoea test, which may be useful since both infections cause similar symptoms. For a more comprehensive overview, the comprehensive STI test allows you to get tested for 11 common sexually transmitted infections at once. 

How can I prevent chlamydia?

To prevent chlamydia, it is essential to consistently use condoms during vaginal, anal, and oral sex. Regular STI testing and open communication about test results are especially important when you have multiple partners or are starting a new relationship. Thorough cleaning or refraining from sharing sex toys also significantly reduces the risk of infection. The following overview summarizes the most important prevention measures:

Chlamydia prevention tips:

• Use condoms during vaginal, anal, and oral sex.
• Get regularly tested for sexually transmitted infections (STIs).
• Communicate openly about sexual health.
• Clean sex toys thoroughly or avoid sharing them.
• Educate yourself about chlamydia and be aware of the risks.

Summary

It is possible to have chlamydia and still receive a negative test result. This may be due to testing too early, inadequate sample collection, or laboratory errors. In such cases, repeat testing or additional diagnostic procedures may be necessary to reliably confirm the infection. When testing, it is important to consider the diagnostic window, which refers to the period between infection and the point at which the bacteria become detectable. For chlamydia infections, this window can range from 1 to 3 weeks.