Acid-fast (Mycobacteria) Smear and Culture With Reflex to Identification
Also known as: Blood Mycobacteria Culture, Culture, Acid-Fast (Sputum, Tissue, Urine, and Gastric Contents), Culture, Blood, Mycobacteria, Mycobacteria Culture (Sputum, Tissue, Urine, and Gastric Contents)
Use
Isolate and identify mycobacteria
Special Instructions
Specimen processing includes N-acetyl-L-cystine-sodium hydroxide treatment or equivalent to concentrate samples. Smears are not performed on blood samples or when less than 2 mL of fluid is available. Additional charges apply for identification procedures using PCR, MALDI-TOF, or nucleic acid sequencing. Cultures may detect Nocardia species and other aerobic actinomyces, and appropriate identification will be conducted.
Limitations
Biopsy and body fluid samples have varying efficacy in diagnosing tuberculosis, with sputum and bronchial washing cultures offering higher yields. Some mycobacterial pathogens such as Mycobacterium marinum, Mycobacterium haemophilum, and Mycobacterium genavense require special incubation conditions and media for cultivation, which must be communicated to the laboratory. Sensitivity of gastric aspirate for detecting M. tuberculosis in children is low, while the presence of Mycobacterium smegmatis in genital secretions can produce false positives in urine smears. Mycobacterium avium complex can be isolated from stool samples in patients with AIDS, necessitating ruling out other pathogens for conclusive diagnosis.
Methodology
Culture-based
Biomarkers
LOINC Codes
- 94540-2
- 50941-4
- 8100-0
- 11545-1
Result Turnaround Time
43-56 days
Related Documents
For more information, please review the documents below
Specimen
Sputum
Volume
5-10 mL
Minimum Volume
2 mL
Container
Sterile container with tight screw-cap seal or green-top (sodium heparin) tube or yellow-top (SPS) tube or Para-Pak® White
Collection Instructions
Collect first morning sputum, not saliva. Collect each of the three separate specimens on separate days.
Storage Instructions
Refrigerate. If sample is to be split for other tests, divide at time of collection so each portion is transported at the appropriate temperature.
Causes for Rejection
Inadequate specimen quantity, swabs from non-superficial exudate sources, use of expired transport media or inappropriate devices, prolonged transport delays, leaking specimens, unlabeled specimens, use of lithium heparin tubes, eSwab devices, paraffin blocks, fixatives, or frozen specimens.
Stability Requirements
| Temperature | Period |
|---|---|
| Refrigerated | 7 days |
Other tests from different labs that may be relevant