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Test ID: CGRNA Chlamydia trachomatis and Neisseria gonorrhoeae, Nucleic Acid Amplification, Varies

Reporting Name

Chlamydia/Gonorrhoeae Amplified RNA

Useful For

Detection of Chlamydia trachomatis or Neisseria gonorrhoeae

 

This test is not intended for use in medico-legal applications.

 

This test is not useful for the detection of Chlamydia pneumoniae.

Clinical Information

Chlamydia is caused by the obligate intracellular bacterium Chlamydia trachomatis and is the most prevalent sexually transmitted bacterial infection (STI) in the United States.(1,2) In 2010, 1.3 million documented cases were reported to the CDC.(2) Given that 3 out of 4 infected women and 1 out of 2 infected men will be asymptomatic initially, the actual prevalence of disease is thought to be much greater than reported.(2) The organism causes genitourinary infections in women and men and may be associated with dysuria as well as vaginal, urethral, or rectal discharge. In women, complications include pelvic inflammatory disease, salpingitis, and infertility. Approximately 25% to 30% of women who develop acute salpingitis become infertile.(2) Complications among men are rare but include epididymitis and sterility. Rarely, genital chlamydial infection can cause arthritis with associated skin lesions and ocular inflammation (Reiter syndrome). C trachomatis can be transmitted from the mother during delivery and is associated with conjunctivitis and pneumonia in the newborn. Finally, C trachomatis may cause hepatitis and pharyngitis in adult.

 

Once detected, the infection is easily treated by a short course of antibiotic therapy.(2) Annual Chlamydia screening is now recommended for all sexually active women age 25 years and younger and for older women with risk factors for infection, such as a new sex partner or multiple sex partners.(2) The CDC also recommends that all pregnant women be given a screening test for chlamydia infection.(2) Repeat testing for test-of-cure is not recommended after treatment with a standard treatment regimen unless patient compliance is in question, reinfection is suspected, or the patient's symptoms persist. Repeat testing of pregnant women, 3 weeks after completion of therapy, is also recommended to ensure therapeutic cure.(2)

 

Gonorrhea is caused by the bacterium Neisseria gonorrhoeae. It is also a very common STI, with 301,174 cases of gonorrhea reported to CDC in 2009.(1,2) Like Chlamydia, many infections in women are asymptomatic, and the true prevalence of gonorrhea is likely much higher than reported.(1,2) The organism causes genitourinary infections in women and men and may be associated with dysuria as well as vaginal, urethral, or rectal discharge. Complications include pelvic inflammatory disease in women and gonococcal epididymitis and prostatitis in men. Gonococcal bacteremia, pharyngitis, and arthritis may also occur. Infection in men is typically associated with symptoms that would prompt clinical evaluation. Given the risk for asymptomatic infection in women, screening is recommended for women at increased risk of infection (eg, women with previous gonorrhea or other STI, inconsistent condom use, new or multiple sex partners, and women in certain demographic groups such as those in communities with high STI prevalence.)(2) The CDC currently recommends dual antibiotic treatment due to emerging antimicrobial resistance.(2)

 

Culture was previously considered to be the gold standard test for diagnosis of C trachomatis and N gonorrhoeae infections. However, these organisms are labile in vitro, therefore, precise specimen collection, transportation, and processing conditions are required to maintain organism viability, which is necessary for successful culturing. In comparison, nucleic acid amplification testing (NAAT) provides superior sensitivity and specificity and is now the recommended method for diagnosis in most cases.(2-5) Immunoassays and non-amplification DNA tests are also available for C trachomatis and N gonorrhoeae detection, but these methods are significantly less sensitive and less specific than NAAT.(2-5)

 

Improved screening rates and increased sensitivity of NAAT testing have resulted in an increased number of accurately diagnosed cases.(2-5) Improved detection rates result from both the increased performance of the assay and the patients' easy acceptance of urine testing. Early identification of infection enables sexual partners to seek testing and/or treatment as soon as possible and reduces the risk of disease spread. Prompt treatment reduces the risk of infertility in women.

Interpretation

A positive result indicates that rRNA of Chlamydia trachomatis or Neisseria gonorrhoeae is present in the specimen tested and strongly supports a diagnosis of chlamydial or gonorrheal infection.

 

A negative result indicates that rRNA for C trachomatis or N gonorrhoeae was not detected in the specimen.

 

The predictive value of an assay depends on the prevalence of the disease in any particular population. In settings with a high prevalence of sexually transmitted disease, positive assay results have a high likelihood of being true-positives. In settings with a low prevalence of sexually transmitted disease, or in any setting in which a patient's clinical signs and symptoms or risk factors are inconsistent with gonococcal or chlamydial urogenital infection, positive results should be carefully assessed and the patient retested by other methods (eg, culture for N gonorrhoeae), if appropriate.

 

A negative result does not exclude the possibility of infection. If clinical indications strongly suggest gonococcal or chlamydial infection, additional specimens should be collected for testing. A result of indeterminate indicates that a new specimen should be collected.

Report Available

1 to 4 days

Day(s) Performed

Monday through Saturday

Clinical Reference

1. Centers for Disease Control and Prevention. 2002. Reporting of laboratory-confirmed chlamydial infection and gonorrhea by providers affiliated with three large Managed Care Organizations-United States, 1995-1999. MMWR Morb Mortal Wkly Rep. 2002;51:256-259

2. Centers for Disease Control and Prevention: Sexually Transmitted Diseases Treatment Guidelines, 2015. MMWR Morb Mortal Wkly Rep. 2015;64(RR-03):1-137

3. Crotchfelt KA, Pare B, Gaydos C, Quinn TC: Detection of Chlamydia trachomatis by the GEN-PROBE AMPLIFIED Chlamydia trachomatis Assay (AMP CT) in urine specimens from men and women and endocervical specimens from women. J Clin Microbiol. 1998 Feb;36(2):391-394

4. Gaydos CA, Quinn TC, Willis D, et al: Performance of the APTIMA Combo 2 assay for detection of Chlamydia trachomatis and Neisseria gonorrhoeae in female urine and endocervical swab specimens. J Clin Microbiol. 2003 Jan;41(1):304-309

5. Chernesky MA, Jang DE: APTIMA transcription-mediated amplification assays for Chlamydia trachomatis and Neisseria gonorrhoeae. Expert Rev Mol Diagn. 2006 Jul;6(4):519-525

Method Name

Transcription Mediated Amplification

Specimen Type

Varies


Necessary Information


Specimen source is required.



Specimen Required


Submit only 1 of the following specimens:

 

Swab specimen must be collected using an Aptima Collection Unisex Swab (T583) or Aptima Collection Multitest Swab (T584). These swabs are contained in the Aptima Collection Kit.

 

Supplies: Swab, Aptima Male/Female Collection (T583)

Specimen Type: Endocervix

Container/Tube: Aptima Collection Unisex Swab

Specimen Volume: Swab

Collection Instructions:

1. Use cleaning swab (white shaft) to remove excess mucus from endocervix and discard.

2. Insert second swab (blue shaft) 1 to 1.5 cm into endocervical canal, and rotate swab gently for 30 seconds. Avoid touching vaginal wall when removing swab.

3. Place second swab into transport tube provided in collection kit. Snap off swab at score line so swab fits into closed tube.

4. Cap tube securely, and label tube with patient's entire name, and date and time of collection.

5. Transport and store swab container at 2 to 30° C (refrigerate is preferred temperature) within 60 days of collection. If longer storage is needed, freeze at -20 to -70° C for 12 months.

 

Supplies: Swab, Aptima Multitest Swab Specimen Collection Kit (T584)

Specimen Type: Vaginal

Container/Tube: Aptima Collection Multitest Swab

Specimen Volume: Swab

Collection Instructions:

1. Insert swab (pink shaft) about 5 cm past introitus and rotate gently for 30 seconds.

2. Place swab into transport tube provided in collection kit. Snap off swab at score line so swab fits into closed tube.

3. Cap tube securely, and label tube with patient's entire name, and date and time of collection.

4. Transport and store swab container at 2 to 30° C (refrigerate is preferred temperature) within 60 days of collection. If longer storage is needed, freeze at -20 to -70° C for 12 months.

 

Supplies: Swab, Aptima Male/Female Collection (T583)

Specimen Type: Urethra (Males Only)

Container/Tube: Aptima Collection Unisex Swab

Specimen Volume: Swab

Collection Instructions:

1. Patient should not have urinated for at least 1 hour prior to collection.

2. With a rotating movement, insert swab (blue shaft) 2 to 4 cm into urethra.

3. Once inserted, rotate swab gently at least 1 full rotation using sufficient pressure to ensure swab comes into contact with all urethral surfaces. Allow swab to remain inserted for 2 to 3 seconds.

4. Place swab in transport tube provided in collection kit. Snap off swab at score line so swab fits into closed tube.

5. Cap tube securely, and label tube with patient's entire name, and date and time of collection.

6. Transport and store swab container at 2 to 30° C (refrigerate is preferred temperature) within 60 days of collection. If longer storage is needed, freeze at -20 to -70° C for 12 months.

 

Supplies: Aptima Urine Transport Tube (T582)

Specimen Type: Urine (Males and Females)

Container/Tube: Aptima Urine Specimen Transport Tube

Specimen Volume: 15-20 mL

Collection Instructions:

1. Patient should not have urinated for at least 1 hour prior to specimen collection.

2. Patient should collect first portion of random voided urine (first part of stream) into a sterile, plastic, preservative-free container.

3. Transfer 2 mL of urine into the urine specimen transport tube using the disposable pipette provided within 24 hours of collection. The correct volume of urine has been added when the fluid level is between the black fill lines on the urine transport tube. Place the labels on the transport tube so the black fill lines are still visible for volume confirmation at Mayo Clinic Laboratories.

4. Transport and store urine specimen transport container at 2 to 30° C (refrigerate is preferred temperature) within 30 days of collection. If longer storage is needed, freeze at -20 to -70° C for 12 months.

 

Supplies: Aptima Thin Prep Transport Tube (T652)

Specimen Type: ThinPrep Specimen (Endocervix)

Container/Tube: ThinPrep (also called PreservCyt) Collection Kit

Specimen Volume: 1 mL

Collection Instructions:

1. Aliquot ThinPrep specimen for Chlamydia and/or Neisseria testing before processing for Pap smear. For each specimen, use a new pair of clean gloves.

2. Vortex ThinPrep/PreservCyt vial 3 to 10 seconds. Within 1 minute of vortexing:

a. Transfer 1 mL of specimen into the Aptima Specimen Transfer Tube using a disposable transfer pipette or a pipette tip containing a filter (aerosol barrier or hydrophobic plug).

b. Process only 1 ThinPrep and transfer tube set at a time.

c. Recap Aptima Specimen Transfer Tube tightly and gently invert 3 times to mix.

3. Label Aptima transfer tube with appropriate label.

4. Use remainder of ThinPrep specimen for Pap testing.

5. Transport and store specimen transfer container at 2 to 30° C (refrigerate is preferred temperature) within 60 days of collection. If longer storage is needed, freeze at -20 to -70° C for 12 months.

 

Swab, Aptima Male/Female Collection (T583)

Swab, Aptima Multitest Swab Specimen Collection Kit (T584)

Specimen Type: Oral/throat or rectal/anal

Container/Tube: Aptima Collection Multitest Swab or Aptima Swab Collection System

Specimen Volume: Swab

Collection Instructions:

1. Swab site using Aptima Collection Multitest Swab or Aptima Collection Unisex Swab.

Note: The white swab provided within the collection kit is a cleaning swab and should not be used for collection. Discard the white cleaning swab.

2. Place collection swab in transport tube provided in collection kit. Snap off swab at score line so swab fits into closed tube.

3. Cap tube securely and label tube with patient's entire name and collection date and time.

4. Transport swab container and store (refrigerated is preferred) within 60 days of collection.


Specimen Minimum Volume

Endocervical in PreservCyt: 1mL
Urine: 2 mL
Swabs (Throat/Oral, Anal/Rectal, Endocervical, Urethral, Vaginal): Entire Collection

Specimen Stability Information

Specimen Type Temperature Time Special Container
Varies Refrigerated (preferred) APTIMA VIAL
  Ambient  APTIMA VIAL
  Frozen  APTIMA VIAL

Reference Values

Chlamydia trachomatis

Negative

 

Neisseria gonorrhoeae

Negative

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

87491-Chlamydia trachomatis

87591-Neisseria gonorrhoeae

LOINC Code Information

Test ID Test Order Name Order LOINC Value
CGRNA Chlamydia/Gonorrhoeae Amplified RNA 64017-7

 

Result ID Test Result Name Result LOINC Value
SRC14 SOURCE: 31208-2
SRC17 SOURCE: 31208-2
34875 Neisseria gonorrhoeae amplified RNA 43305-2
34874 Chlamydia trachomatis amplified RNA 43304-5

Profile Information

Test ID Reporting Name Available Separately Always Performed
CTRNA Chlamydia trachomatis Amplified RNA Yes Yes
GCRNA Neisseria gonorrhoeae Amplified RNA Yes Yes

Forms

If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:

-General Request (T239)

-Microbiology Test Request (T244)

Mayo Clinic Laboratories | Microbiology and Infectious Disease Catalog Additional Information:

mml-gisti