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Test Code M58 Acid-Fast Stain for Mycobacterium

Biohazard Infectious

Additional Codes


PowerChart: AFB Smear

Epic: LAB266 AFB Stain

MA Cerner: Acid Fast Smear

Test Method

Auromine-O stained smear with microscopic examination.

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 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 to the laboratory within 1 hour of collection. 

  • Sputum: Collect a series of 3-5 single specimens collected early in the morning from a deep productive cough. A volume of 5-10 mL is required. Pooled specimens are not acceptable. 
  • 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.


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

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.

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.

Useful For

Detection of mycobacteria in clinical specimens.

LOINC Code Information

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