Acid-Fast Bacillus (AFB) Culture and AFB Stain with Reflex to Mycobacterium tuberculosis Complex Detection and Rifampin Resistance by PCR
Also known as: MC AFBR
Use
This comprehensive panel is designed to detect and identify Mycobacterium tuberculosis complex species, as well as test for rifampin resistance. It begins with an acid-fast bacillus culture and stain. If a smear is positive, it reflexes to PCR amplification for detecting the presence of M. tuberculosis complex and any associated rifampin resistance. This test is crucial for diagnosing tuberculosis and guiding appropriate antibiotic treatment by identifying resistance mechanisms.
Special Instructions
Each individual specimen requires a separate order submission. Care should be taken to follow specific guidelines for collection (three specimens at 8-24 hour intervals, one being a first-morning specimen). It is important to notify the laboratory if mycobacteria like M. genavense or M. haemophilum are suspected, as they require special handling. Similarly, specimens from cystic fibrosis patients need additional decontamination procedures.
Limitations
Specimens less than 5 mL will receive a disclaimer about suboptimal volume, potentially compromising the recovery of acid-fast bacilli. Multiple specimens collected from the same site within 24 hours are unacceptable, as are dry materials or specimens on swabs. Freeze storage is unacceptable due to its potential impact on the viability of organisms. Positive results may not require repeat PCR testing as they will continue yielding positive results, providing limited additional clinical value.
New York Approved
Methodology
Culture-based
Biomarkers
LOINC Codes
- 539-7
Result Turnaround Time
1-62 days
Related Documents
For more information, please review the documents below
Specimen
Other
Volume
5-10 mL
Minimum Volume
1 mL
Container
50 ml sterile specimen transport tube preferred
Collection Instructions
Three sputum specimens should be collected at 8-24 hour intervals (24 hours when possible) and at least one first-morning specimen.
Storage Instructions
Refrigerated.
Causes for Rejection
Multiple same-site specimens (more than one in 24 hours), dry material, or material collected and transported on a swab.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 24 hours |
| Refrigerated | 1 week |
| Frozen | Unacceptable |
Other tests from different labs that may be relevant