Mycobacterium avium Complex Susceptibility−Broth Dilution
Also known as: AFB Susceptibility Testing, M avium Complex Susceptibility Testing, MAC Susceptibility Testing
Use
Determine the susceptibility of Mycobacterium avium complex isolates to a profile of antimycobacterial agents. Testing is recommended for isolates from patients with previous macrolide therapy, patients who relapse while on macrolide therapy, or patients with initial isolates from blood, tissue, or clinically relevant respiratory specimens. Repeat susceptibility is recommended after 3 months (disseminated disease) or 6 months (chronic pulmonary disease) if the cultures are still positive or if there is no clinical improvement.
Special Instructions
It is important to note that susceptibility cannot be reported if the organism fails to grow in the test medium. Additionally, susceptibilities cannot be performed on mixed cultures. Repeat susceptibility testing is recommended after 3 months for disseminated disease or 6 months for chronic pulmonary disease if cultures remain positive or if there is no clinical improvement.
Limitations
The test has not been cleared or approved by the FDA. Susceptibility results are invalid if the organism fails to grow in the test medium, and the test cannot be performed on mixed cultures. Also, ethambutol is not reported for M. avium complex isolates due to lack of correlation between MIC values and clinical outcomes, as established in studies.
Methodology
Culture-based
Biomarkers
LOINC Codes
- 29576-6
- 40699-1
- 5-Dec
- 185-9
- 189-1
- 16623-1
- 225-3
- 29254-0
- 335-0
- 31037-5
- 16100-0
- 428-3
- 460-6
- 516-5
Result Turnaround Time
21-30 days
Related Documents
For more information, please review the documents below
Specimen
Other
Volume
Pure culture isolate on an AFB conventional solid medium or a minimum of 1 mL of AFB broth medium
Minimum Volume
Not provided
Container
Conventional or broth medium, tightly sealed, in etiologic agent packaging
Storage Instructions
Maintain media at room temperature.
Causes for Rejection
Specimen received in leaking or in broken transport tube or vial; specimen received in expired transport medium; mixed culture; unlabeled culture or name discrepancy between specimen and request label