Mycobacteria (AFB) Smear and Culture
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| WSLH Department: | CDD - Communicable Disease Division |
| WSLH Test Code: | MM00250 |
| Day(s) Performed: | Monday - Friday |
| Turn-around Time: | Smear: Within 24 hours of receipt; Culture: 6 Weeks for a negative culture. If specimen is contaminated with non-mycobacteria and needs re-decontamination, culture may take up to 12 weeks. |
| Recommended Uses: | ** Smear: Presumptive diagnosis of mycobacterial disease; rapid identification of most infectious TB cases, e.g. those that are smear positive; to follow progress of TB patients on chemotherapy; one of the criteria to determine if a patient may be discharged from hospital or isolation. ** Culture: Determine presence of mycobacteria and identify the species. |
| Contraindications: | |
| Additional Tests Performed: |
| Patient Preparations: | Collect specimens prior to chemotherapy. Sterile preparation of site if applicable. |
| Specimen Requirements: | ** Sputum: Volume no less than 3ml, optimal volume 5-10 ml in sterile container. Collect three consecutive specimens, each collected in 8-24 hour intervals with at least one being an early morning specimen (CDC MMWR 2005: 54, RR-17); ** Other respiratory specimens (BAL, bronch wash, etc.): 5-10ml in sterile container; ** Gastric Lavage: 5-10 ml, must use WSLH Kit #13 (contains buffer for neutralization), collected in a series of 3 specimens over 3-5 days. ** Stool: 1 gram in sterile container; ** Tissue Biopsy: 1 gram in sterile container; Greater than or equal to 3Three or more specimens from the same collection site will be automatically pooled into a single specimen for smear and culture. ** Urine: 40 ml, first-morning, clean catch in sterile container (24-hour pooled specimens are unacceptable); ** Body Fluids (pleural, pericardial etc.): 5-10ml in sterile container; ** Whole Blood: 10 ml in SPS blood collection tube or Heparin tube (do not use EDTA); ** Bone Marrow: As much as available in sterile container or SPS tube; ** CSF: As much as available in sterile container (minimum of 1 ml required); ** Skin Lesions: scrapings or exudates; ** Swabs are not acceptable. ** AFB smears are not performed on blood specimens. |
| Specimen Handling & Transport: | For all specimens except for blood and bone marrow: Store at 2-8 degrees Celsius. Ship with cool pack. Do not freeze. For blood and bone marrow: Store and ship at ambient temperature and ship as soon as possible (within 48 hours). Use pressure-resistant bags as inner packaging. Call WSLH (800-262-1013) for information on free next-day courier service. |
| Collection Kit/Container: |
Mycobacteria (AFB,TB) Gastric Specimens
TB Sputum/Legionella |
| Collection Instructions: | Special Instructions for Sputum: Collect three specimens, each collected in 8-24 hour intervals with at least one being an early morning specimen (CDC MMWR 2005: 54, RR-17). Optimally 5mL of sputum, minimum 3mL. Sputum specimens collected less than 8 hours apart will be pooled into a single smear and culture. Special Instructions for Gastric Lavage: Collect fasting specimen soon after patient awakens in order to obtain sputum swallowed during sleep; place in neutralizing buffer immediately. |
| Unacceptable Conditions: | Blood collected in EDTA tube; gastric lavage specimens that have not been neutralized (buffered); 24-hour pooled specimens; sputum specimens <3ml; swab specimens; specimens received more than 7 days after collection; frozen specimens; specimens with visible food; saliva. |
| Requisition Form: |
CDD Requisition Form A
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| Required Information: | Laboratory regulations require the following minimum information to be provided on the requisition form for a specimen to be accepted for testing: Patient name or unique identifier; date and time of collection, patient date of birth and sex, specimen type/site of collection, test request(s), clinician name and UPIN, and address for reporting results. Please be certain that name/identifier on the form matches that on the specimen label. |
| Results Include: | Smear: Negative, positive (with quantification), questionable. Culture: Negative for Mycobacteria; Species identification when mycobacterial growth is detected; Culture overgrown with non acid-fast organisms |
| Limitations: | Negative results obtained from specimens submitted on swabs are not reliable. A negative test result does not rule out infection with mycobacteria. Improper specimen collection and handling may compromise assay performance. AFB Smears are not performed on blood because of very low bacterial concentration. |
| Additional Tests Recommended: | **Both Mycobacteria smear and culture (MM00250) should be ordered for diagnostic specimens. ** For direct detection of mycobacteria from clinical specimens, see M. tuberculosis complex (TB) PCR and M. avium complex (MAC) PCR. ** For susceptibility testing of clinically significant mycobacteria isolates, see M. tuberculosis (TB) Susceptibility first line drugs, and M. avium complex (MAC) Susceptibility. |
| Additional Comments: | ** Fee-exempt TB/MAC (M. avium complex) real-time PCR is performed automatically on the first smear-positive specimen from WI residents not previously diagnosed with tuberculosis or NTM disease. Fee-for-service real-time PCR is available on all other smear-positive specimens. ** Susceptibility testing is performed automatically on all initial M. tuberculosis complex isolates. The initial M. tuberculosis complex isolate is genotyped as part of the CDC universal genotyping program. **If a fastidious Mycobacterium species (M. haemophilum, M. genavense, etc.) is suspected, notify WSLH either prior to or at time of specimen submission so that appropriate culture conditions can be set up. |
| Methodology: | Acid fast smear: Auramine O stain. Culture by BACTEC MGIT 960 System. Mycobacteria identification may include one or more of the following analyses: MALDI-TOF, real-time PCR, 16S/rpoB gene sequencing, and growth characteristics. |
| Includes: | Acid Fast Smear and Culture |
| CPT Code: | 87116, 87206, 87015 |
| Price: | $84.00 Price Effective 1/1/25 |