How Chlamydia Is Diagnosed

Chlamydia is a sexually transmitted infection (STI) that is caused by bacteria and often has no symptoms. Despite this, chlamydia can cause complications that can ultimately lead to infertility and other health concerns.

While chlamydia can be self-checked at home, it's still a good idea to see your healthcare provider for an official diagnosis.

This article explains how you can find out if you have chlamydia. It also covers what to expect during the diagnostic tests, as well as next steps after you get your results.

What Tests Can Detect Chlamydia?

There are a few different tests that look for the presence of Chlamydia trachomatis, the bacterium that causes this STI. These tests can be performed if you have symptoms or as a routine screening if you are sexually active.

Healthcare providers and clinics may differ in which tests they prefer to use. The most common tests are nucleic acid amplification tests (NAATs). These detect the bacteria by looking for traces of their genetic material.

These tests can be run on a:

• Urine specimen
• Urethral swab of the penis, which is a swab of the tube through which urine, or pee, passes out of the body
• Endocervical swab, which is a swab of the area around the opening of the uterus, or womb
• Vaginal swab, which is a swab of the walls of the vagina

If you've been tested or treated for other STIs, don't assume that a chlamydia test was included. Not only does chlamydia require its own test, but the treatments for some of the other STIs are ineffective against chlamydia.

Self Checks and At-Home Tests

If you think you may have chlamydia, you may want to go over a symptom checklist. Common signs and symptoms of chlamydia may include discharge from the penis or vagina, a burning feeling while you pee, and/or pain in the rectum and/or testicles.

Because many individuals don't show any symptoms, ordering an at-home STI test may be a good first step. You may want to do so if you are nervous to speak with your healthcare provider about your sexual history, the medical office is far away, or it is difficult to get an appointment.

Research done by scientists from the Centers for Disease Control and Prevention (CDC) suggests that:

• More people are likely to get tested using at-home tests.
• The majority of people prefer to take an STI test at home rather than at a medical office.
• The majority of healthcare providers surveyed would be willing to use these at-home tests in their office as an STI screening tool, which suggests they have comparable accuracy to the traditional tests done in medical offices.

Another study supports this similar accuracy when vaginal swabs are self-collected from assigned females and urine samples are self-collected from assigned males.

Keep in mind that these tests are not FDA approved. However, there are companies that have partnered with Clinical Laboratory Improvement Amendments (CLIA)-certified labs, which meet federal regulations for diagnostic testing. Others also partner with labs certified by the College of American Pathologists (CAP).

What to Expect During Chlamydia Test

The way that healthcare providers test for chlamydia will depend on your genitalia and sexual history. This is due to the different locations the bacteria can infect.

How Do They Test for Chlamydia in Individuals With a Vagina?

For an endocervical swab, your healthcare provider will insert a speculum, a device that helps keep your vaginal walls open, to view your cervix, or the lower end of the uterus. They will use a thin swab to retrieve a sample from your cervix, which will then be sent to a lab.

Less commonly, a vaginal swab may be done, which requires inserting a swab into the vagina and gently rotating it to collect a sample.

If you aren't comfortable getting an endocervical or vaginal swab, you can request a urine test. Keep in mind that urine samples tend not to detect chlamydia as accurately as vaginal and endocervical swabs.

How Do They Test for Chlamydia in Individuals With a Penis?

Your healthcare provider will either ask you for a urine sample or collect a sample from inside the head of your penis using a small swab. This sample is then sent to a lab for analysis.

Not all practitioners perform urine tests for chlamydia. However, if you aren't comfortable getting swabbed, you can ask for a urine test.

What About Rectal and Oral Swabs?

Rectal swabs and oral swabs may also be considered for those who have receptive anal sex or unprotected oral sex. These tests are known as extragenital, or outside of the genital region, testing. These tests are important to do if chlamydia is suspected but your urine test came back negative.

Rectal and oral swabs can be collected at home and dropped off the same day at a lab, or done in a medical office or lab.

How Often Should You Get Tested?

It's currently recommended that you should be tested:

• Every year if you are a sexually active assigned female, or individual with a cervix under 25 years old, with retesting three months after treatment, if applicable
• During pregnancy if you are under 25 years old, with retesting during the third trimester if you are at risk
• Four weeks after treatment and again within three months if you are a pregnant individual
• If you are an assigned female older than 25 at an increased risk
• If you are a pregnant individual older than 25 at an increased risk
• Every year if you are an assigned male who has sex with other assigned males and every three to six months if you are at an increased risk
• If you are at an increased risk and an assigned male who has sex with assigned females
• If you are transgender, over 25, and have a cervix. or under 25 and have an increased risk

Screening has been found to be very effective and to significantly lower the risk of an assigned female developing pelvic inflammatory disease (PID), an infection that can lead to infertility and other serious health concerns.

In assigned males, screening can help lower the risk of developing urethral infections and swollen and painful testicles from untreated chlamydia.

When to Request Testing

There are a number of reasons why healthcare providers fail to test for STIs and why you may need to request testing yourself. Even with screening guidelines in place, many cases go untested and undetected.

Make sure to request a chlamydia test if one of your partners has been diagnosed with an STI, or if you have an increased risk of getting this infection.

If asking your healthcare practitioner for the test is hard for you, keep in mind that chlamydia is one of the most common STIs. It's important to find a healthcare provider who you feel comfortable discussing your sexual history with.

Results and Follow-Ups

If you do get a positive test result, it's important to talk to any sexual partners you've had in the past two months and suggest that they see a healthcare provider for testing and treatment.

As with any form of lab tests, there is the potential for errors. Even though the sensitivity of chlamydia tests used today is good, they may still miss infections. This is known as a false-negative result. What this means is that if you have any symptoms, you should follow up with your practitioner—even if you tested negative.

There is also a small risk of false-positive results, in which a person gets a positive chlamydia test result but does not actually have the infection. This is of less concern in general, as most people tolerate the treatments for chlamydia well.

When Should I Test Again for Chlamydia?

Getting retested about three months after treatment for chlamydia is recommended for both assigned males and assigned females. This should be done even if your partner was also treated.

Reinfection is possible, and most cases that are found after treatment are because of this possibility, rather than the failure of the treatment itself.

Pregnant individuals should be retested three weeks after treatment is completed. Pregnant individuals at high risk should also get tested again in the third trimester.

Differential Diagnosis

Vaginal discharge has many causes other than chlamydia. Some may include infections like bacterial vaginosis (BV) or yeast infections, as well as hormonal changes. Likewise, there is a wide range of conditions that can cause pain with intercourse, bleeding between periods or during intercourse, and more.

For all individuals, pain and burning with urination can have many possible causes, including bladder infections and other STIs. 

So, while a healthcare professional may suspect one issue or another, if you present symptoms at all, lab tests are essential to making an accurate chlamydia diagnosis and choosing the appropriate treatment.

Summary

Chlamydia is a common STI that often has no symptoms. Urine or swab tests are typically used to detect the presence of the bacteria that cause this STI.

Chlamydia can be self-checked at home by noting your symptoms, or by self-collecting a sample using an at-home test. How often you should test and retest will depend on many factors.

It's always best to follow up with your healthcare provider if you believe you may have chlamydia.