Acid-Fast Bacillus (AFB) Culture and AFB Stain
Also known as: MC AFB
Use
The Acid-Fast Bacillus (AFB) Culture and AFB Stain test is the gold standard for diagnosing the presence of mycobacteria organisms, including Mycobacterium tuberculosis. It is crucial for identifying both common and rare mycobacterial infections. Identification and susceptibility tests assist in the appropriate management of tuberculosis and other mycobacterial diseases. The test includes identification procedures for positive cultures and susceptibility tests for significant isolates, providing comprehensive management for suspected mycobacterial infections.
Special Instructions
For accurate test results, three sputum specimens should be collected at 8-24 hour intervals, preferably with at least one first-morning specimen. Each specimen must be submitted as an individual order. If testing for PZA susceptibility for M. tuberculosis complex isolates is required, contact your local public health lab or the CDC. ARUP handles susceptibility testing for other first-line drugs, namely rifampin, isoniazid, and ethambutol. The specimen source is required for processing.
Limitations
Stool, blood, bone marrow, grossly bloody specimens, dry material, and materials collected and transported on a swab are unacceptable. AFB susceptibility testing is not performed for Mycobacterium gordonae. Susceptibility testing will require additional requests for some organisms like M. kansasii and M. marinum, and emulsification in blood culture phenotype should not be used alone for clarithromycin. Special culture setup considerations are necessary for Mycobacterium xenopii and cystic fibrosis patients.
New York Approved
Methodology
Culture-based
Biomarkers
LOINC Codes
- 543-9
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
Collection Instructions
Transfer (for each collection) 5-10 mL to a sterile container.
Patient Preparation
Collect three sputum specimens at 8-24 hour intervals (24 hours when possible) and at least one first-morning specimen.
Storage Instructions
Refrigerated.
Causes for Rejection
Dry material or material collected and transported on a swab. Stool, blood, bone marrow, grossly bloody specimens.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 24 hours |
| Refrigerated | 1 week |
| Frozen | Unacceptable |