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HelpMayo Test ID SAFB Acid-Fast Smear for Mycobacterium, Varies
Ordering Guidance
For the preferred test for rapid, direct detection of Mycobacterium tuberculosis from clinical specimens, order MTBRP / Mycobacterium tuberculosis Complex, Molecular Detection, PCR, Varies.
Necessary Information
Specimen source is required.
Specimen Required
Submit only 1 of the following specimens:
Specimen Type: Body fluid
Container/Tube: Sterile container
Specimen Volume: 1 mL
Specimen Type: Bone marrow
Container/Tube: SPS/Isolator System or green top (lithium heparin)
Specimen Volume: Entire collection
Specimen Type: Gastric washing
Container/Tube: Sterile container
Specimen Volume: 10 mL
Collection Instructions: Neutralize specimen within 4 hours of collection with 100 mg of sodium carbonate per 5 to 10 mL of gastric wash.
Specimen Type: Respiratory
Sources: Bronchoalveolar lavage fluid, bronchial washing, sputum
Container/Tube: Sterile container
Specimen Volume: 4 mL
Collection Instructions: Collect 3 respiratory specimens for acid-fast smears and culture in patients with clinical and chest X-ray findings compatible with tuberculosis. These 3 specimens should be collected at 8- to 24-hour intervals (24 hours when possible) and should include at least 1 first-morning specimen.
Specimen Type: Stool
Supplies: Stool Collection Kit, Random (T635)
Container/Tube: Sterile container
Specimen Volume: 5-10 g
Specimen Type: Tissue
Container/Tube: Sterile container
Specimen Volume: 5-10 mm
Collection Instructions: Collect a fresh tissue specimen.
Specimen Type: Urine
Container/Tube: Sterile container
Specimen Volume: 2 mL
Collection Instructions: Collect a random urine specimen.
Specimen Type: Swab
Additional Information: Fresh tissue or body fluid is the preferred specimen type instead of a swab specimen. Recovery of mycobacteria and aerobic actinomycetes from swabs is variable.
Sources: Wound, tissue, or body fluid
Container/Tube: Culture transport swab (noncharcoal) Culturette
Specimen Volume: Adequate specimen
Collection Instructions:
1. Before collecting specimen, wipe away any excessive amount of secretion and discharge, if appropriate.
2. Obtain secretions or fluid from source with sterile swab.
3. If smear and culture are requested or both a bacterial culture and mycobacterial culture are requested, collect a second swab to maximize test sensitivity.
Useful For
Detection of acid-fast bacilli in clinical specimens
Reflex Tests
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| TBT | Concentration, Mycobacteria | No, (Bill Only) | No |
| TISSR | Tissue Processing | No, (Bill Only) | No |
Testing Algorithm
When this test is ordered, the reflex tests may be performed at an additional charge.
See Meningitis/Encephalitis Panel Algorithm in Special Instructions.
Method Name
Auramine-Rhodamine Stain
Reporting Name
Acid Fast Smear For MycobacteriumSpecimen Type
VariesSpecimen Minimum Volume
Body fluid: 0.5 mL
Respiratory specimen: 3 mL
Fresh tissue: pea-sized piece
If a mycobacterial culture is also requested:
Body fluid: 1.5 mL
Respiratory specimen: 3 mL
Fresh tissue: pea-sized piece
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Varies | Refrigerated (preferred) | 7 days | |
| Ambient | 7 days |
Reject Due To
| Blood or serum Prepared slide, glass slide, microscope slide |
 Reject |
Clinical Information
Mycobacterium tuberculosis is a leading infectious disease cause of death worldwide. The Centers for Disease Control and Prevention has reported a rise in the incidence of tuberculosis associated with AIDS, foreign-born cases, and increased transmission in high-risk populations. There has also been a rise in the number of M tuberculosis strains that exhibit resistance to one or more antituberculosis drugs. The public health implications of these facts are considerable. Because M tuberculosis is readily spread by airborne particles, rapid diagnosis and isolation of infected persons is important. Nontuberculous mycobacteria infections also cause significant morbidity and mortality in humans, particularly in immunocompromised persons. Detection of acid-fast bacilli in sputum specimens allows rapid identification of individuals who are likely to be infected with mycobacteria while definitive diagnosis and treatment are pursued.
Reference Values
Negative (reported as positive or negative)
Interpretation
Patients whose sputum specimens are identified as acid-fast positive should be considered potentially infected with Mycobacterium tuberculosis, pending definitive diagnosis by molecular methods or mycobacterial culture.
Cautions
Artifacts may exhibit nonspecific fluorescence and be confused with organisms.
Clinical Reference
1. American Thoracic Society/Centers for Disease Control and Prevention/Infectious Diseases Society of America: Controlling Tuberculosis in the United States. Am J Respir Crit Care Med. 2005;172:1169-1227
2. American Thoracic Society: An Official ATS/IDSA Statement: Diagnosis, Treatment, and Prevention of Nontuberculous Mycobacterial Diseases. Am J Respir Crit Care Med. 2007;175:367-416
Method Description
Auramine-rhodamine fluorochrome stain prepared and read with fluorescent microscope.(Pfyffer GE, Palicova F: General characteristics, laboratory detection, and staining procedures. In Manual of Clinical Microbiology. 10th edition. Edited by J Versalovic, KC Carroll, G Funke, et al: Washington, DC, ASM Press, 2011, pp 472-502)
Day(s) Performed
Monday through Sunday
Report Available
1 daySpecimen Retention Time
3-7 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.CPT Code Information
87206
87176-Tissue processing (if appropriate)
87015-Mycobacteria culture, concentration (if appropriate)
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| SAFB | Acid Fast Smear For Mycobacterium | 676-7 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| SAFB | Acid Fast Smear For Mycobacterium | 676-7 |