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HelpTest ID MTBRP Mycobacterium tuberculosis Complex, Molecular Detection, PCR
Useful For
Rapid detection of Mycobacterium tuberculosis complex DNA, preferred method
Detection of Mycobacterium tuberculosis, when used in conjunction with mycobacterial culture
Reflex Tests
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| TBT | Mycobacteria Culture, Conc | No, ( Bill Only) | No |
Testing Algorithm
When this test is ordered, the reflex test may be performed and charged.
Method Name
Real-Time Polymerase Chain Reaction (PCR)
(PCR is utilized pursuant to a license agreement with Roche Molecular Systems, Inc.)
Reporting Name
M tuberculosis Complex PCRSpecimen Type
VariesThe high sensitivity of amplification by PCR requires the specimen to be processed in an environment in which contamination of the specimen by Mycobacterium tuberculosis DNA is unlikely.
If a single specimen is being shared between mycobacteria culture, acid-fast smear, and/or Mycobacterium tuberculosis PCR, a minimum volume of 2 mL for body fluid, 3 mL for respiratory specimen, or a pea-sized piece of tissue should be obtained. Specimen volumes less than indicated may decrease sensitivity of testing. If insufficient volume is submitted, test or tests will be canceled.
Forms: If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:
Microbiology Test Request Form (T244) (http://www.mayomedicallaboratories.com/it-mmfiles/microbiology_test_request_form.pdf)
Neurology Test Request Form-General (T732) (http://www.mayomedicallaboratories.com/it-mmfiles/neurology-request-form.pdf)
Preferred Specimens: Body fluid, cerebrospinal fluid (CSF), ocular fluid, respiratory (eg, bronchoalveolar lavage [BAL], bronchial washing, sputum), stool, fresh tissue, bone, bone marrow, or urine
Acceptable Specimens: If no fresh specimen is available, digested respiratory specimens treated with N-acetyl-L-cysteine (NALC)/NaOH are acceptable (eg, BAL, bronchial washing, respiratory fluid, sputum, or tracheal secretion), as are NALC/NaOH-treated gastric washings.
Specimen must arrive within 7 days of collection; specimen >7 days will be rejected.
Specimen source is required.
Submit only 1 of the following specimens:
Specimen Type: Body fluid
Sources: Body, bone marrow aspirate, ocular, or CSF
Container/Tube: Sterile container
Specimen Volume: 1 mL
Additional Information: Only fresh, non-NALC/NaOH-digested body fluid is acceptable.
Specimen Type: Gastric washing
Container/Tube: Sterile container
Specimen Volume: 2 mL
Collection Instructions: Neutralize specimen within 4 hours of collection with 20 mg of sodium carbonate per 2of gastric washing.
Specimen Type: Respiratory
Sources: BAL, bronchial washing, or sputum
Container/Tube: Sterile container
Specimen Volume: 1 mL if only PCR ordered or 3 mL if PCR ordered with smear and culture
Specimen Type: Stool
Container/Tube: Sterile container
Specimen Volume: 5-10 g
Additional Information: Only fresh, non-NALC/NaOH-digested stool is acceptable.
Specimen Type: Tissue
Sources: Fresh tissue, bone, or bone marrow biopsy
Container/Tube: Sterile container
Specimen Volume: 5-10 mm
Collection Instructions: Keep moist with sterile water or sterile saline
Additional Information: Only fresh, non-NALC/NaOH-digested tissue is acceptable.
Specimen Type: Urine
Container/Tube: Sterile container
Specimen Volume: 1 mL
Collection Instructions: Collect a random urine specimen.
Acceptable
Specimen Type: NALC/NaOH-digested respiratory specimens
Sources: Lavage fluid, bronchial washing, gastric washing, respiratory fluid, sputum, or tracheal secretion
Container/Tube: Sterile container
Specimen Volume: 2 mL
Collection Instructions:
1. Submit digested specimen treated with NALC/NaOH.
2. Clearly indicate on container and order form that specimen is a digested specimen.
Specimen Minimum Volume
Body fluid: 0.5 mL; Respiratory specimen-nondigested: 0.5 mL; Fresh tissue or bone: 5 mm; NALC-NaOH-digested specimen: 1 mL; Gastric washing: 1 mL; Stool: 5 g; Urine: 0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Varies | Refrigerated (preferred) | 7 days |
| Frozen | 7 days |
Clinical Information
Each year, Mycobacterium tuberculosis accounts for approximately 1.4 million deaths and is responsible for 9 million newly diagnosed cases of tuberculosis worldwide. Mycobacterium tuberculosis is spread from person-to-person via respiratory transmission, and has the potential to become resistant to many or all of the antibiotics currently used if antimycobacterial treatment is not promptly initiated. Therefore, rapid and accurate detection of Mycobacterium tuberculosis in patient specimens is of clinical and public health importance.
Conventional culture methods can generally detect Mycobacterium tuberculosis in 2 to 3 weeks, although up to 8 weeks of incubation may be required in some instances. Developed at Mayo Clinic, this rapid PCR assay detects Mycobacterium tuberculosis complex DNA directly from respiratory specimens and other specimens without waiting for growth in culture and, therefore, the results are available the same day the specimen is received in the laboratory. A mycobacterial culture should always be performed in addition to the PCR assay. The PCR assay is rapid but the culture has increased sensitivity over the PCR assay. The PCR assay targets a unique sequence within the katG gene, which is present in members of the Mycobacterium tuberculosis complex. In addition, the assay can detect genotypic resistance to isoniazid mediated by mutations in the katG target, when present.
Reference Values
Not applicable
Cautions
This test should always be performed in conjunction with mycobacterial culture.
This rapid PCR assay detects Mycobacterium tuberculosis complex nucleic acid and, therefore, does not distinguish between viable, disease-related organisms and nucleic acid persisting from prior infection. Test results should be correlated with patient symptoms and clinical presentation before a definitive diagnosis is made.
A negative result does not rule out the presence of Mycobacterium tuberculosis complex or active disease because the organism may be present at levels below the limit of detection for this assay.
This test has not been studied for use with specimens from patients being treated with antituberculous agents and, therefore, should not be used to determine bacteriologic cure or to monitor response to therapy. It is not known how long the PCR assay can remain positive following treatment for Mycobacterium tuberculosis.
The sensitivity of this test with stool specimens is 80% and testing of additional stool specimens should be considered if the result from the first specimen is negative.
Day(s) Performed
Monday through Sunday
Report Available
1 dayPerforming Laboratory
Mayo Medical Laboratories in Rochester
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.CPT Code Information
87556-Mycobacterium tuberculosis, complex, molecular detection, PCR
87015-Mycobacteria culture, concentration (if appropriate)