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Test Code M58 Acid-Fast Stain for Mycobacterium


Additional Codes


PowerChart: AFB Smear

MA Cerner: Acid Fast Smear

Specimen Requirement

5-10 mL Sputum, 5-10 mL Gastric Washings, 40 mL Urine, Tissue, Stool, Body Fluid, 5 mL Bronchial Washings, Bronchial Aspirates, Bronchial Brushings, Blood or Bone Marrow

Additional Specimen Collection Information

Collect the specimen in a sterile, leak proof container. Do not use Cultureswab specimen collection device used for aerobic cultures. Label the specimen appropriately with patient name and two identifiers (patient ID number, DOB, etc.)  [including source, date and time of collection]. Transport the specimen in a sealed, leak proof container within 1 hour of collection. If specimens cannot be transported to the laboratory within one hour, please refrigerate and keep specimen cool while transporting to the laboratory.

  • Sputum:  Collect a series of 3 specimens.  Samples should be collected at 8-24 hour intervals and should include at least one first morning sample. A volume of 5-10ml is required.  Pooled samples are NOT acceptable.  [CAP MIC.31100]
  • Gastric Washings: Gastric washings are collected on patients unable to produce sputum. Three consecutive specimens of 5-10 mL, collected in a sterile container from a fasting patient in the early morning are superior to a single aspirate. Since gastric contents are toxic to acid-fast bacilli, specimens must be processed within 4 hours of collection. 
  • Urine: A series of 3 single midstream specimens voided in the early morning are required. 24 hour pooled specimens are unacceptable. A minimum of 40 mL of urine is required. 
  • Tissue: Collect tissue specimen asceptically and transport to the laboratory immediately. 
  • Stool: Pass the stool into a clean, dry container or bedpan. Do not allow urine to  contaminate the specimen in the collection container. 
  • Body Fluids: Collect asceptically. 
  • Bronchial Washings, Aspirates or Brushings:  Collect in a sterile container. 
  • Blood: Collect in SPS (yellow-top) tube. 
  • Bone Marrow: Collect in SPS (yellow-top) tube. Prior to the bone marrow procedure, prep the top of the yellow-top vacuum tube with an alchol wipe. Using a sterile needle and syringe, remove approximately half of the liquid from the tube. Immediately after marrow aspiration, and before any other samples are aliquotted, dispense a portion of the aspirate into the tube with a sterile transfer device. Leave sufficient amount of aspirate in the syringe for smear preparation, referred testing and clot sections.

Useful For

Detection of mycobacteria in clinical specimens.


Acid Fast Smear: Monday through Sunday, allow 24 hours turn-around time after the specimen is received in Microbiology.

CPT Code Information

87206 Identification of Organism from Primary Source and Sensitivity Studies; Fluorescent or acid-fast stain for bacteria, fungi, parasites, viruses or cell types.

LOINC Code Information

11545-1 Microscopic Observation [Identifier] In Unspecified Specimen By Acid Fast Stain

Test Method

Auramine-O stained smear with microscopic examination.

Reference Values

Acid Fast Smear: No Acid Fast Bacilli seen. The Acid Fast Smear is reported as presence or absence of Acid Fast Bacilli.

  • Critical Value: Acid Fast Bacilli seen.
    All positive Acid Fast Smears are called to the nurse's station or physician office and Epidemiology.