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Test Code M57 Acid Fast Culture and Stain for Mycobacterium


Additional Codes


PowerChart: AFB Culture and Smear

MA Cerner: Acid Fast Culture & Stain

Specimen Requirement

5-10 mL Sputum, 5-10 mL Gastric Washings, 40 ml Urine, Tissue, Stool, Body Fluid, 5 mL Bronchial (Washings, Aspirates, 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 two identifiers, patient name and another identifier, (patient ID number, DOB, etc.) include specimen 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 3-5 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: Collect 40 mL (minimum 10 mL) of the first morning urine into a sterile urine container. Refrigerate the specimen within 1 hour of collection. Microbiology will send to State Hygienic Laboratory for testing.
  • 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. Microbiology Dept will send to the State Hygienic Laboratory for testing.
  • 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. Microbiology Dept will send the specimen to the State Hygienic Laboratory for testing.

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.

Acid Fast Culture: A final report is sent in 8 weeks if the culture is negative when performed at MercyOne-Microbiology.

If performed at State Hygienic Lab, a final report is sent in 6 weeks if the acid fast culture is negative.

CPT Code Information

87116 Culture tubercle or other acid-fast bacilli any source, with isolation and presumptive identification of isolates

87206 Fluorescent or acid-fast stain for bacteria, fungi, parasites, viruses or cell types.

87015 Concentration for infectious agents.

LOINC Code Information

50941-4 Mycobacterium sp [Presence] In Unspecified Specimen By Organism Specific Culture

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

Test Method

Fluorescence detection; BD MGIT

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. 

Acid Fast Culture: No Acid Fast Bacilli seen.

  • Critical Value: Acid Fast Bacilli isolated.
    As soon as growth occurs the nurse's station or physician office and Epidemiology are called. Preliminary reports are sent on positive cultures. All isolates are sent to the State Hygienic Laboratory in Iowa City for identification.