Can a Urine Test Detect STIs?

Several sexually transmitted infections (STIs) can be detected using a urine test, which is becoming more and more available. Urine chlamydia tests and gonorrhea tests are a lot more pleasant than having to have your cervix (women) or urethra (men) swabbed and are quickly becoming standard practice.

It may be more difficult to find urine testing for other STIs, such as trichomoniasis or human papillomavirus (HPV), however.

This article discusses which STIs can be detected using a urine test and the limitations of this type of testing.

Purpose of Urine Testing for STIs

It used to be that STI testing, particularly for bacterial STIs, was very uncomfortable.

Men who thought they might have a bacterial STI like chlamydia or gonorrhea got tested by having a swab inserted into their urethra. Women had to undergo a pelvic exam, during which a cervical swab would be taken and tested for bacteria.

The fact that STI testing was uncomfortable and invasive made it less likely that people would undergo regular STI screening.

That probably contributed to what is sometimes known as the hidden epidemic of asymptomatic STIs. Because many STIs have no symptoms, the only way to detect them is through testing. When people aren't tested regularly, they can spread STIs to their partners without even knowing it.

Urine testing makes it easier for people to undergo STI testing as part of their regular medical care. Note, however, that STI testing is still not a standard part of most annual exams.

Urine Testing vs. Bacterial Culture

Urine testing is currently primarily used to detect bacterial STIs. Chlamydia and gonorrhea urine tests are widely available. Trichomoniasis urine tests are also available, but they are less common.

The gold standard for diagnosing bacterial STIs, such as chlamydia and gonorrhea, used to be a bacterial culture. That involved attempting to grow bacteria out of samples that were taken directly from the cervix or urethra.

These days, bacterial DNA testing is considered a better option. It works differently than a bacterial culture. Instead of trying to grow bacteria, these tests just look for bacterial DNA. This can be done using a process called ligase chain reaction (LCR) or with other DNA amplification techniques.

These types of testing are sensitive to even very small amounts of bacterial DNA. Even better, they do not require a live bacterial sample. As such, they can be run on urine samples—not just urethral or cervical swabs.

For most people, the thought of getting a gonorrhea urine test or chlamydia urine test is a lot less intimidating than the thought of needing a physical exam. It's also possible to test for these STIs using a urine test at home. With these at-home STI tests, you collect your own sample and send it to a lab. Results are typically available online within days.

Before the Test

You do not need any special preparation for a urine STI test. However, it is good to talk to your healthcare provider beforehand about what STIs you are going to be tested for.

Ask why the specific tests have been chosen. You may also want to request additional testing if you are at risk for other STIs that your healthcare provider is not planning to test for.

Finally, you should ask how long the results will take to come back and whether the healthcare provider's office will call you if the results are negative. Some offices only call when test results are positive.

During and After the Test

When you have a urine STI test, it is usually during a regular appointment. You will be asked to pee into a sample collection cup or tube. That tube or cup will be given to one of the medical staff.

Your urine sample will then be sent out to a lab or tested at the clinic. You can leave as soon as you are done giving the sample or when your appointment is finished.

Interpreting Results

Urine STI test results to identify bacterial DNA are usually available within hours. One test called the XPert CT/NG, provides results within 90 minutes.

A positive test result means that you are infected with that STI and should be treated. A negative test means there was no evidence that you were infected with that STI at the time of the test.

Even with a negative test, it is important to undergo regular STI testing if you are sexually active and not in a mutually monogamous relationship (neither you nor your partner have sex with other people). Depending on your number of sexual partners you may want to be screened once a year, or more often.

Urine STI testing is not a one-time thing. You could get infected in your next sexual encounter.

Effectiveness of Urine Tests for STIs

Some people still question whether urine testing is as effective as other forms of testing in detecting bacterial STIs like chlamydia and gonorrhea.

Research shows that this type of urine testing is particularly effective for males. This is because urine passes through the most common site of infection (the penile urethra), in men.

In contrast, the most common site of female infection (the cervix) is not on the pathway that urine travels out of the body. Therefore, tests on urine samples from women tend to detect fewer STIs than tests on vaginal or cervical swabs. In fact, it's been shown that self-collected vaginal swabs are closer in effectiveness to clinician-collected cervical swabs than urine testing.

A 2015 review that examined 21 studies on the relative effectiveness of using different types of samples to detect chlamydia and gonorrhea found that:

• For chlamydia testing in women, the sensitivity (the ability for a test to correctly identify a patient with a disease) and specificity (the ability for a test to correctly identify a patient without a disease) were 87% and 99%, respectively, for urine samples compared to cervical samples.
• For chlamydia testing in men, the sensitivity and specificity were 88% and 99%. respectively, for urine samples compared to urethral samples.
• For gonorrhea testing in women, the sensitivity and specificity were 79% and 99%, respectively, for urine samples compared to cervical samples.
• For gonorrhea testing in men, the sensitivity and specificity were 92% and 99%, respectively, for urine samples compared to urethral samples.

By and large, these results are relatively consistent across studies. Overall, science suggests that urine testing still does a pretty good job of finding most infected individuals. For some women, self-swab testing may be a more acceptable alternative to a pelvic exam if urine testing isn't available.

That is great news for people who want to be tested for gonorrhea and chlamydia in a less invasive way. However, some other STI tests still do require either a physical examination or a blood draw.

Urine Tests for Oral and Anal Infections

Most infections with gonorrhea and chlamydia are asymptomatic. The fact that many people have no symptoms means that the only way to detect and treat these infections is through screening.

In men, these diseases usually infect the urethra, and in women the cervix. However, it is possible to get both of these diseases in the throat, from oral sex. Anal sex can also lead to rectal chlamydia and rectal gonorrhea infections.

Currently, it is recommended that men who have sex with men undergo urine, throat, and anal screening once a year. Other people who regularly have unprotected oral or anal sex should consider a similar screening regimen. People who only engage in vaginal intercourse can get by with urine testing alone for gonorrhea and chlamydia.

Risks and Contraindications

Urine testing is completely safe. You will provide a urine sample, that you collect yourself, to the healthcare provider. They or their lab will then use special tests to identify whether it contains bacterial DNA.

There are no circumstances under which urine STI testing is inadvisable.

Other STI Urine Tests

Currently, only gonorrhea and chlamydia are commonly tested for by using urine samples. However, there are other STIs that can be tested for this way.

Trichomoniasis

Trichomoniasis urine tests are becoming more widely available. Like gonorrhea and chlamydia, trichomoniasis is a very common, curable STI.

As such, it makes a lot of sense for healthcare providers to test for this STI at the same time. Urine testing is one option for doing that.

As with chlamydia and gonorrhea, some research suggests that urine testing may not be as effective as doing similar tests on a vaginal swab, however.

HPV

Human papillomavirus (HPV) is another STI that can be detected using urine tests. As with trichomoniasis, urine tests for HPV are not yet widely available. However, research suggests that testing first-voided urine (urine released when you start emptying your bladder) can be an effective way to screen for cervical cancer.

That said, when compared to Pap smears, urine HPV tests have the same problem as other HPV tests—many HPV infections go away on their own. Therefore, it may be more useful to know if there are problematic cervical changes rather than whether someone has HPV. You can only do that with a Pap smear or VIA (visual inspection with acetic acid) test.

Other

There are no commercial urine tests available for syphilis or herpes. While the Food and Drug Administration (FDA) did approve an HIV urine test in the 1990s, it is rarely if ever used.

Oral and blood samples are far more likely to be used for HIV testing. There is even a home test for HIV that uses saliva samples.

Summary

For a long time, research suggested that cervical and urethral testing were slightly more effective than urine testing for STIs. However, newer studies suggest that some urine tests may actually be better at picking up certain infections.

Even when they're not superior, FDA-approved urine tests are more than good enough in most circumstances. Furthermore, the tests continue to get better with time.

For most people, it's far more important to get tested for STIs than to worry about getting the best STI test. Getting tested on a urine sample may not be quite as efficient as getting tested using a healthcare provider-collected swab. However, it is much better than not getting tested at all.