Catch the Answers

The Screening

Chlamydia and gonorrhea can be diagnosed by testing urine or swab specimens collected from the site(s) of the body at risk for infection. When testing for chlamydia and gonorrhea health care professionals should ask the patient which areas are at risk for infection so that proper tests are performed for more accurate results. A urine test will not detect a vaginal, cervical, rectal, or pharyngeal infection; therefore, health care providers must ask about the specific screening needs of a patient.  

Asymptomatic infections are common among both men and women, and to detect chlamydial and gonorrheal infections health care providers should frequently rely on screening tests. Patients whose condition has been diagnosed as chlamydia and/or gonorrhea should also be tested for other STDs; urine samples and swab specimens can and should be tested for both chlamydia and gonorrhea.

Test results are usually available within three to five days; depending upon when the sample was sent and when it arrived at the laboratory. Health care professionals should encourage patients to call in if symptoms appear or worsen during that time.  In those instances it is recommended to start treatment before the test confirms a chlamydia and/or gonorrhea infection.

Screening Procedures for Women:
C. trachomatis and N. gonorrhoeae infections in women can be diagnosed by testing urine or swab specimens collected from the endocervix, vagina, rectum, or pharynx. A urine test only detects urethral infections. Women who have only a vaginal, cervical, rectal, or pharyngeal infection will receive a negative urine test result. Urine must pass over the site of infection in order for bacteria to be collected and detectable in the specimen for a positive test result; it does not pass over the vagina during urination.

Swabbing areas of the body at risk for infection provides more comprehensive results, especially for women since they have more areas anatomically at risk. Health care providers should have all pap smears from sexually active women screened for STDs. All sexually active women should be encouraged to get tested, including those who are pregnant. All pregnant women should be screened for STDs at their first prenatal visit.  

Women should be tested for chlamydia and gonorrhea at least once a year if:

• 25 or younger and sexually active
• Older than 25 and having sex with more than one partner
• Older than 25 and have a new sex partner
• Pregnant

 
Screening Procedures for Men:
A urethral infection in men can be diagnosed by testing a urethral swab or urine specimen. Receiving a negative urine test result simply means that there is no chlamydia or gonorrhea infection in the urethra.

Swab specimens for men can also be collected from the rectum and pharynx. Testing all areas of the body at risk for infection provides more comprehensive results.

Men should be tested for chlamydia and gonorrhea at least once a year if:

• 25 or younger and sexually active
• Older than 25 and having sex with more than one partner
• Older than 25 and have a new sex partner

The Tests

Chlamydia Tests
Culture, direct immunofluorescence, EIA, nucleic acid hybridization tests, and NAATs are available for the detection of C. trachomatis on endocervical and male urethral swab specimens. NAATs are the most sensitive tests for these specimens and are FDA-cleared for use with urine, and some tests are cleared for use with vaginal swab specimens. The majority of tests, including NAAT and nucleic acid hybridization tests, are not FDA-cleared for use with rectal swab specimens, and chlamydia culture is not widely available for this purpose. Some noncommercial laboratories have initiated NAAT of rectal swab specimens after establishing the performance of the test to meet CLIA requirements.


 
Gonorrhea Tests
Culture, nucleic acid hybridization tests, and NAATs are available for the detection of genitourinary infection with N. gonorrhoeae. Culture and nucleic acid hybridization tests require female endocervical or male urethral swab specimens. NAAT offer the widest range of testing specimen types because they are FDA-cleared for use with endocervical swabs, vaginal swabs, male urethral swabs, and female and male urine. However, product inserts for each NAAT vendor must be carefully examined to assess current indications, because FDA-cleared specimen types might vary. In general, culture is the most widely available option for the diagnosis of infection with N. gonorrhoeae in nongenital sites (e.g., rectum and pharynx). Nonculture tests are not FDA-cleared for use in the rectum and pharynx. Some NAATs have the potential to cross-react with nongonococcal Neisseria and related organisms that are commonly found in the throat. Some noncommercial laboratories have initiated NAATs of rectal and pharyngeal swab specimens after establishing the performance of the test to meet CLIA requirements.