Mycobacterium tuberculosis Complex Detection and Rifampin Resistance (PCR), Acid-fast Bacillus (AFB) Smear, and AFB Culture With Reflex to Identification and Susceptibility Testing (Sputum)
Use
This test is designed to detect the presence of the Mycobacterium tuberculosis complex and determine rifampin resistance using PCR methodology. In addition, the test includes an acid-fast bacillus (AFB) smear and AFB culture to further confirm the presence of tuberculosis. The test can reflex to identification and susceptibility testing, providing comprehensive information on the pathogen's identity and its antimicrobial resistance. This makes it especially useful in diagnosing tuberculosis and guiding appropriate treatment strategies, especially when drug resistance is suspected or confirmed.
Special Instructions
First morning sputum specimens are required for accurate detection, and proper specimen handling and storage are critical. The specimen should be placed in a sterile container with a tight screw-cap seal and refrigerated if needed. Ensure that the specimen is not contaminated or compromised by inadequate sealing or inappropriate transport methods.
Limitations
The test cannot detect the presence of Mycobacterium tuberculosis complex if the bacterial load in the sputum is below the detection threshold. False negatives may occur due to specimen dilution or improper handling. Additionally, the test may not detect all forms of rifampin resistance if mutations occur outside the regions targeted by the PCR assay. Cultures may not be successful if the bacteria are non-viable or if the sputum contains inhibitors of mycobacterial growth.
Methodology
PCR-based (RT-PCR)
Biomarkers
LOINC Codes
- 8100-0
- 11545-1
- 50941-4
- 14556-5
- 33634-7
Result Turnaround Time
43-56 days
Related Documents
For more information, please review the documents below
Specimen
Sputum
Volume
5 mL
Minimum Volume
Not provided
Container
Sterile container with tight screw-cap seal
Collection Instructions
Collection should occur in the morning with a first morning sputum sample, avoiding contamination with saliva.
Storage Instructions
Refrigerate the specimen if it cannot be processed immediately. If the sample will be used for multiple tests, divide it at collection to ensure appropriate temperature transport for each.
Causes for Rejection
Quantity not sufficient; inappropriate specimen source; leaking; unlabeled or mismatched labels; prolonged delay; fixative contamination.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | not specified |
| Refrigerated | 7 days |
| Frozen | not applicable |