Mycobacterium tuberculosis Complex, Molecular Detection and Rifampin Resistance, PCR, Sputum
Use
The test is used for the rapid detection of Mycobacterium tuberculosis DNA from respiratory specimens for the diagnosis of pulmonary tuberculosis. It also provides presumptive detection of rifampin resistance based on the presence of resistance-associated mutations, helping in making timely and appropriate therapeutic decisions.
Special Instructions
The test is performed using the Cepheid Xpert MTB/RIF assay, which utilizes a real-time PCR method. Results should be interpreted in conjunction with mycobacterial culture, which is necessary for epidemiological strain typing and antimicrobial susceptibility testing. Specimens must arrive within 7 days of collection to avoid rejection due to delay.
Limitations
The test detects nucleic acid from Mycobacterium tuberculosis and does not distinguish between viable organisms and residual DNA from prior infections. Negative results do not rule out disease due to potential low levels of bacteria below the detection limit. Rifampin resistance results are preliminary and require confirmation by sequencing or phenotypic susceptibility testing.
FDA ApprovedNew York Approved
Methodology
PCR-based (RT-PCR)
Biomarkers
LOINC Codes
- 89371-9
- 31208-2
- 88874-3
- 89372-7
Result Turnaround Time
0-1 days
Related Documents
For more information, please review the documents below
Specimen
Sputum
Volume
3 mL
Minimum Volume
1.5 mL
Container
Sterile container
Collection Instructions
If a single specimen is being shared between mycobacterial culture, acid-fast smear, and/or M tuberculosis PCR, a minimum volume of 3 mL is required. Clearly indicate on the container and order form that the specimen is a digested specimen if treated with NALC/NaOH.
Storage Instructions
Refrigerated (preferred) 7 days/Ambient 72 hours
Causes for Rejection
Specimen received greater than 7 days from collection will be rejected due to delay.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 72 hours |
| Refrigerated | 7 days |