• Also Known As:
  • Chlamydia Nucleic Acid Amplification Test (NAAT or NAT)
  • Chlamydia/GC STD Panel
  • Chlamydia Culture
  • Formal Name:
  • Chlamydia trachomatis Testing
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At a Glance

Why Get Tested?

To screen for and diagnose a chlamydia infection

When To Get Tested?

  • For women, yearly screening is recommended if you are sexually active and younger than age 25, or 25 or older and at increased risk for chlamydia infection; when you are pregnant or considering pregnancy.
  • For men, yearly screening is recommended if you are a man who has sex with men.
  • When you have symptoms of chlamydia, such as pain during urination, vaginal discharge and abdominal pain (for women) or unusual discharge from the penis, pain on urination or painful, swollen testicles (for men)
  • When your newborn has conjunctivitis

Sample Required?

For women, vaginal swabs are the optimal sample for genital chlamydia testing. A healthcare practitioner may use a swab or small brush to collect a sample of cells or fluid from your vagina during a pelvic examination. Sometimes, you may collect your own vaginal sample for testing (self-collection).

For men, a healthcare practitioner may use a swab to collect a sample from your urethra, the tube within your penis that allows urine to flow from your bladder.

Urine samples can be used to test both men and women. As you begin to urinate, collect the initial portion of your urine stream (first-catch) in a container provided by the healthcare practitioner or laboratory.

Sometimes, a healthcare practitioner may use a swab or brush to collect a sample from other areas that may be infected, such as the rectum, throat or eye.

Test Preparation Needed?

Tell your healthcare practitioner about any use of antibiotics or, if you are a woman, douches or vaginal creams. You may be asked to avoid using these within 24 hours before testing vaginal samples since they may affect test results. Menstruation will not affect results. You may be instructed to wait one to two hours after you last urinated before collecting a urine sample. Follow any instructions you are given.

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What is being tested?

Chlamydia is one of the most common bacterial sexually transmitted diseases (STD) in the United States and can cause serious complications if not treated. Chlamydia testing identifies the bacteria Chlamydia trachomatis as the cause of your infection.

The preferred method for chlamydia testing is the nucleic acid amplification test (NAAT) that detects the genetic material (DNA) of Chlamydia trachomatis. It is generally more sensitive and specific than other chlamydia tests and can be performed on a vaginal swab on women or urine from both men and women, which eliminates the need for a pelvic exam in women.

Screening for, diagnosing, and treating chlamydia is very important in preventing long-term complications and spread of the infection to others. Chlamydia infections are especially common among people 15 to 24 years of age. The Centers for Disease Control and Prevention (CDC) estimates that 2.86 million Americans are infected with chlamydia each year and notes that women are frequently re-infected if their partners don’t get treatment. The actual number of cases may be higher since many people do not experience any symptoms and do not get tested and diagnosed. Still, over one million new cases are reported each year.

Chlamydia is generally spread through sexual contact (oral, vaginal, or anal) with an infected partner. Risk factors include having multiple sex partners, infection with another STD at the same time or previous STD infection, and not using a condom correctly and consistently.

Many people with chlamydia infections have no symptoms and some may experience only mild symptoms. Signs and symptoms of chlamydia are similar to and can be confused with those cause by another STD, gonorrhea, so tests for these infections are often done at the same time.

Chlamydia is easily treated with a course of antibiotics. If not diagnosed and treated, it can cause severe reproductive and other health problems.

In women, untreated chlamydia infections can lead to pelvic inflammatory disease (PID) from infections that start on the cervix but spread to the fallopian tubes and ovaries. This can cause:

  • Long-term (chronic) pelvic pain
  • Infertility
  • An increased risk of tubal (ectopic) pregnancy, which can be fatal

If you are infected while pregnant, you may experience premature labor, premature rupture of the membranes and your baby may be born with a low birth weight. You can pass the infection to your baby during childbirth. Infected babies are at risk of developing complications such as pneumonia or conjunctivitis, an inflammation that, left untreated, can threaten eyesight.

Rarely, men who are not treated may experience infertility.


How is the test used?

Chlamydia testing is used to screen for and diagnose sexually transmitted infections caused by the bacteria Chlamydia trachomatis.

Testing for Chlamydia trachomatis and Neisseria gonorrhoeae (gonorrhea) is often done at the same time since the infections caused by these two bacteria can have similar signs and symptoms. These bacteria may be acquired at the same time, and you may have infections with both. A definitive diagnosis is important since the two infections require different antibiotic treatment.

Repeat testing is recommended to ensure that treatment has been effective. This is done about three months after you have completed treatment.

When is it ordered?


Because many infected people do not have any noticeable symptoms, a number of health organizations recommend regular chlamydia screening for certain people:


All sexually active women younger than age 25 and sexually active women age 25 and older who are at increased risk should get yearly screening for chlamydia, according to the Centers for Disease Control and Prevention (CDC) and the American College of Obstetricians and Gynecologists (ACOG). The U.S. Preventive Services Task Force (USPSTF) and the American Academy of Pediatrics also recommend routine screening for these women (the USPSTF says age 24 and younger).

Examples of risk factors for chlamydia infection include:

  • Previous chlamydia infections, even if you have been treated
  • Having STDs, especially HIV
  • Having new or multiple sex partners
  • Having a sex partner diagnosed with an STD
  • Using condoms inconsistently
  • Exchanging sex for money or drugs
  • Using illegal drugs
  • Living in a detention facility

For pregnant women, the CDC recommends screening for chlamydia during the first trimester or first prenatal visit. For women younger than age 25 or at increased risk of infection, testing is repeated in the third trimester. Pregnant women diagnosed with chlamydia should be retested about 3 months after completing treatment. (See Pregnancy for more information.)


The CDC recommends that men who have sex with men get chlamydia screening at least annually. Health organizations do not recommend routine screening for sexually active, heterosexual men with no symptoms. However, your healthcare practitioner may recommend screening if there is a high number of cases (prevalence) of STDs in your community.


Chlamydia testing may also be done when your sex partner has been diagnosed with chlamydia or when you have signs and symptoms of chlamydia.

For women, if symptoms occur, they may include:

  • Bleeding between your menstrual periods and after sexual intercourse
  • Abdominal pain
  • Pain during sex
  • Pain while urinating and/or urinating more often
  • Abnormal vaginal discharge

For men, symptoms may include:

  • Pus or milky discharge from your penis
  • Pain when urinating and/or urinating more often
  • Pain, tenderness and swelling of your testicles

Both men and women can get an infection in their rectum and may be tested when they have symptoms such as itching, inflammation, pain, discharge and/or bleeding from the rectum.

Testing for both chlamydia and gonorrhea may be done when your newborn has symptoms of conjunctivitis, such as redness and swelling of the eye, and discharge.

Women or men treated for chlamydia should be retested three months after their treatment.

What does the test result mean?

A positive test indicates you have an active chlamydia infection that requires treatment with antibiotics.

A negative test means only that there is no evidence of infection at the time of the test. If you are at an increased risk, it is important that you have screening tests performed yearly to check for possible infection, especially since re-infection is common, particularly among teenagers.

If you are infected, your sexual partner(s) should be tested and treated as well.

How long does it take to get results?

This will depend on the lab performing the test and the method used to diagnose your infection. Nucleic acid amplification (NAAT) methods can give results in one day to a few days.

Where can I get tested?

Visit the Healthfinder.gov webpage Get Tested for Chlamydia and Gonorrhea to find out where you can get tested. You can input your zip code and find a local testing site.

How can chlamydia be prevented?

The most reliable ways to avoid infection with chlamydia or any sexually transmitted disease are to abstain from oral, vaginal, and anal sex or to be in a long-term, mutually monogamous relationship with an uninfected partner. People who are sexually active should correctly and consistently use condoms to reduce the risk of infection with chlamydia and other STDs.

How is chlamydia treated?

Your healthcare practitioner will prescribe antibiotics to treat chlamydia. Antibiotics can cure your infection, but damage from the infection may sometimes be permanent. If symptoms do not resolve after a few days, consult your healthcare provider. You should refrain from having sex until you have completed your treatment and should be re-tested three months after treatment.

If I get treated, can I get chlamydia again?

Yes. Even though treatment will cure your infection, you can get it again if you are exposed again. In fact, reinfection is common, according to the CDC.

Should I tell my partner that I have chlamydia?

Yes, you should tell your sexual partner(s) that you have chlamydia so that they can get tested and treated.

Does having chlamydia put me at greater risk for other STDs?

Yes, people who are infected have a higher risk of contracting other sexually transmitted diseases, including a 3 to 5 times greater risk of acquiring HIV if exposed to it.

Is there anything else I should know?

The Centers for Disease Control and Prevention (CDC) recommends the NAAT testing method for chlamydia, except in cases of child sexual abuse in boys or rectal and oral infections in preteen girls. In these cases, culture is recommended.

View Sources

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