Test ID: MCRNA
Chlamydia trachomatis, Miscellaneous Sites, by Nucleic Acid Amplification (GEN-PROBE)
NY State Approved 
Indicates the status of NY State approval and if the test is orderable for NY State clients.
Useful For Suggests clinical disorders or settings where the test may be helpful
Detection of Chlamydia trachomatis
Testing Algorithm Delineates situation(s) when tests are added to the initial order. This includes reflex and additional tests.
This test is used for specimens that are not FDA approved for this assay. Acceptable non-FDA-approved specimen types are ocular, oral, anal or rectal swabs, and peritoneal fluid.
Method Name A short description of the method used to perform the test
Transcription Mediated Amplification
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Aliases Lists additional common names for a test, as an aid in searching
DNA Probe Chlam/Neis STD Panel
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Specimen source is required.
Submit only 1 of the following specimens:
Swab specimen must be collected using an APTIMA Collection Unisex Swab (Supply T583) or APTIMA Collection Vaginal Swab (Supply T584). These swabs are contained in the APTIMA Collection Kit.
Specimen Type: Oral/throat or ocular (corneal/conjunctiva) or rectal/anal
Container/Tube: APTIMA Swab Collection System (Supply T583)
Specimen Volume: Swab
Collection Instructions:
1. Swab site using APTIMA Collection Unisex Swab.
2. Place 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 date and time of collection.
4. Transport swab container to laboratory and store (refrigerated is preferred) within 60 days of collection.
Specimen Type: Peritoneal fluid (pelvic wash, cul-de-sac fluid)
Container/Tube: APTIMA Specimen Transfer Tube (Supply T652)
Specimen Volume: 1 mL
Collection Instructions:
1. Transfer specimen into the APTIMA Specimen Transfer Tube (Supply T652).
2. Cap tube securely, and label tube with patient's entire name, and date and time of collection.
3. Transport APTIMA Specimen Transfer Tube to laboratory (refrigerated is preferred) within 30 days of collection.
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
| Hemolysis | NA |
| Lipemia | NA |
| Icterus | NA |
| Other | Sources other than those listed above |
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
| Specimen Type | Temperature | Time |
|---|---|---|
| Varies | Refrigerated (preferred) | |
| Ambient | ||
| Frozen | ||
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Chlamydia is caused by the obligate intracellular bacterium Chlamydia trachomatis and is the most prevalent sexually transmitted bacterial infection 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. The organism causes genitourinary infections in women and men and may be associated with dysuria and 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). Chlamydia trachomatis can be transmitted from the mother during delivery and is associated with conjunctivitis and pneumonia. Finally, Chlamydia trachomatis may cause hepatitis and pharyngitis in adults.
Once detected, the infection is easily treated by a short course of antibiotic therapy. 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. 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)
Culture was previously considered to be the gold standard test for diagnosis of Chlamydia trachomatis infection.(2) However, organisms are labile in vitro, and 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.(3-5) Immunoassays and nonamplification DNA tests are also available for Chlamydia trachomatis detection, but these methods are significantly less sensitive and less specific than NAAT.(2)
Improved screening rates and increased sensitivity of NAAT testing have resulted in an increased number of accurately diagnosed cases.(2) Early identification of infection enables sexual partners to seek testing and treatment as soon as possible and reduces the risk of disease spread. Prompt treatment reduces the risk of infertility in women.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
Negative
Interpretation Provides information to assist in interpretation of the test results
A positive result indicates the presence of rRNA Chlamydia trachomatis. This assay does detect plasmid-free variants of Chlamydia trachomatis.
A negative result indicates that rRNA for Chlamydia trachomatis 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 chlamydial urogenital infection, positive results should be carefully assessed and the patient retested by other methods, if appropriate.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
This report is intended for use in clinical monitoring or management of patients; it is not intended for use in medico-legal applications.
Appropriate specimen collection and handling is necessary for optimal assay performance.
Results should be interpreted in conjunction with other laboratory and clinical information.
A negative test result does not exclude the possibility of infection. Improper specimen collection, concurrent antibiotic therapy, presence of inhibitors, or low numbers of organisms in the specimen (ie, below the sensitivity of the test) may cause false-negative test results.
In low-prevalence populations, positive results must be interpreted carefully as false-positive results may occur more frequently than true-positive results in this setting.
In general, this assay should not be used to assess therapeutic success or failure, since nucleic acids from these organisms may persist for 3 weeks or more following antimicrobial therapy.
The presence of mucous does not interfere with this assay. However, this test requires endocervical cells, and if excess mucous is not removed prior to collection, adequate numbers of these cells may not be obtained.
No interference is expected with swab specimens due to:
-Blood
-Lubricants and spermicides
The effects of use of tampons, douching, specimen types other than those listed in Specimen Required, and specimen collection variables have not been determined.
This assay does not detect Chlamydia pneumoniae.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
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, 2010. MMWR Morb Mortal Wkly Rep 2010;59:RR12
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 Description Describes how the test is performed and provides a method-specific reference
The GEN-PROBE APTIMA Combo 2 Assay combines the technologies of target capture, transcription-mediated amplification, and dual kinetic assay. The detection of the rRNA amplification product sequences (amplicon) is achieved using nucleic acid hybridization. Single-stranded chemiluminescent DNA probes are labeled and combine with amplicon to form stable RNA:DNA hybrids. Light emitted from the labeled RNA:DNA hybrids is measured as photon signals in a luminometer.(Package insert: GEN-PROBE APTIMA Combo 2 Assay 501798 Rev A. 04/2009)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Saturday, varies
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
87491
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
| Result ID | Reporting Name | LOINC Code |
|---|---|---|
| SRC11 | SOURCE: | N/A |
| 34507 | C. trach, Misc, Amplified RNA | N/A |
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