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Virology / Serology - Chlamydia/Gonorrhea

Chlamydia trachomatis and Neisseria gonorrhoeae infections are two of the most common sexually transmitted infections worldwide.

Chlamydia are nonmotile, gram-negative, obligate intracellular bacteria. C. trachomatis can cause assorted urogenital infections in addition to asymptomatic infection, which if undiagnosed could lead to pelvic inflammatory disease (PID), ectopic pregnancy, and infertility in women. Children born to infected mothers are at significantly higher risk for inclusion conjunctivitis and chlamydial pneumonia.

N. gonorrhoeae is the causative agent of gonorrheal disease. N. gonorrhoeae are nonmotile, gram-negative diplococci. The majority of gonorrheal infections are uncomplicated lower genital tract infections and may be asymptomatic. However, if left untreated in women, infections can ascend and cause PID. A smaller percentage of persons with gonococcal infections may develop Disseminated Gonococcal Infection (DGI).

The diagnostic testing for C. trachomatis and N. gonorrhoeae at the NC State Laboratory of Public Health is a nucleic acid amplification test (NAAT) that dually detects the presence of C. trachomatis RNA and/or N. gonorrhoeae RNA on a single endocervical swab specimen. Urine testing for C. trachomatis and N. gonorrhoeae is available on a limited basis to pre-approved, select sites.

Please call the Virology/Serology Unit Supervisor at 919-733-7544 for guidance related to the collection and submission of specimens to CDC for cases of suspected LGV.

Specimen Acceptance Policy

Chlamydia trachomatis/Neisseria gonorrhoeae laboratory services are subject to the following guidelines which have been developed to ensure proper patient management and efficient utilization of limited resources.  Only the following specimens will be accepted from local health departments:

Submitted specimens must be accompanied by a fully completed submission form (DHHS #4011).  Failure to supply the requested patient information may result in significantly delayed specimen testing or in specimens being rejected.  Specimens for diagnostic testing not labeled with correct patient identification information will not be tested.  Minimal patient specimen identification includes full first and last name and either SSN or date of birth.  Specimens which, for any reason, are deemed unsuitable or inappropriate for diagnostic testing will not be tested.  Rejected specimens will be properly stored for thirty days pending verbal and/or written notification of the submitter.  Unless alternate arrangements are initiated by the submitter upon notification of specimen rejection, the specimen will be discarded at the end of the holding period.

Specimen Collection

Specimens from the endocervix are obtained by the following procedure:

  1. Remove excess mucus from cervical os and surrounding mucosa using cleaning swab (white shaft swab in package with red printing). Discard this swab.
  2. Insert specimen collection swab (blue shaft swab in package with green printing) into endocervical canal.
  3. Gently rotate swab clockwise for 10 to 30 seconds in endocervical canal to ensure adequate sampling.
  4. Withdraw swab carefully; avoid any contact with vaginal mucosa.
  5. Remove cap from swab specimen transport tube and immediately place specimen collection swab into specimen transport tube.
  6. Carefully break swab shaft at scoreline; use care to avoid splashing contents.
  7. Re-cap swab specimen transport tube tightly.

Urine specimens are obtained by the following procedure:

  1. The patient should not have urinated for at least 1 hour prior to specimen collection.
  2. Direct patient to provide a first-catch urine (approximately 20 to 30 mL of the initial urine stream) into a urine collection cup free of any preservatives. Collection of larger volumes of urine may result in specimen dilution that may reduce test sensitivity. Female patients should not cleanse the labial area prior to providing the specimen.
  3. Remove the cap and transfer 2 mL of urine into the urine specimen transport tube using the disposable pipette provided. The correct volume of urine has been added when the fluid level is between the black fill lines on the urine specimen transport tube label.
  4. Re-cap the urine specimen transport tube tightly. This is now known as the processed urine specimen.

Clearly label specimen transport tube with the patient´s full first and last name and either SSN or date of birth. Complete (DHHS #4011). (downloaded and printed from this website) with the required information.

Specimen Shipping

Properly identified specimen transport tubes and completed submission forms should be sent in goldenrod colored specimen mailers labeled CHLAMYDIA/GONORRHEA DETECTION. For detailed shipping instructions using the double mailers, see Packing Instructions Using Outer Baggie. Ship at ambient temperature by the State Courier or U.S. Mail. Endocervical specimens are stable for 60 days at room temperature after collection and urine specimens are stable for 30 days at room temperature after collection; however, it is advisable to ship as soon as possible to avoid delays in turn-around time of test results.

Specimen collection swab kits and goldenrod colored specimen mailers are available through the NCSLPH online supply ordering system at this website. Store collection materials at room temperature.

Results Reporting

Clinical specimens that test positive for chlamydia and gonorrhea will be reported as "C. trachomatis RNA detected" and "N. gonorrhea RNA detected", respectively. All positive results will include the comment "Therapeutic failure or success cannot be determined with this assay since nucleic acid may persist for several weeks following appropriate antimicrobial therapy." Negative laboratory results for chlamydia and gonorrhea will be reported as "C. trachomatis RNA not detected" and "N. gonorrhea RNA not detected", respectively. An equivocal result for either test will be reported as indeterminate, in which case, another specimen should be properly collected and submitted to resolve the status of the patient. Results should be interpreted in conjunction with patient history and clinical findings.

Chlamydia and gonorrhea test results are available within two working days after receipt of the specimen. These results can be accessed on the main page by clicking on Lab Test Results Lookup.

Data indicates the sensitivity and specificity of the APTIMA assay is nearly 100%. However, it must be remembered that the results of this test are not 100% predictive of every patient’s true infected status.

Relevant Links:

See also:

Last Modified: June 30, 2009 12:21 PM