Acid Fast Bacilli Referred Isolate Identification

Laboratory Fee Schedule

Procedure: MAC0055A

CPT: 87143


Acid Fast Bacilli Referred Isolate Identification


AFB Isolate

Requisition Form


Test Description

Identification of mycobacterial isolates referred to DSHS Laboratory

Pre-Approval Needed


Supplemental Information Required


Supplemental Form(s)


Performed on Specimens from (sources)

Pure isolate from human sources

Sample/Specimen Type for Testing

Mycobacterium species pure isolate in liquid or on solid culture medium

Minimum Volume/Size Required

  • Liquid culture - 2.0 mL

  • Solid culture - Single mature colony

Storage/Preservation Prior to Shipping


Transport Medium


Specimen Labeling

  • Two patient-specific identifiers required (e.g., patient full name, date of birth, Medical record number)

  • Identifiers on specimen must exactly match submission form.

Shipping and Specimen Handling Requirements

  • Ship according to Dangerous Goods Regulations, IATA, and/or CFR 49

  • Category B shipping applies for unidentified isolates

  • Category A shipping applies for Mycobacterium tuberculosis complex


  • High performance liquid chromatography (HPLC)

  • Subculture for purity and morphological examination

Turn-around Time

2 days for identification


  • HPLC may only detect the predominant organism in a mixed culture.

  • Liquid cultures must be instrument positive in order to analyze by HPLC.

Common Causes for Rejection

  • Cultures overgrown by contaminating organisms

  • Cultures broken in transit

Additional Information

Most isolates can be identified as either M. tuberculosis complex or Mycobacterium species, not M. tuberculosis within 2 to 3 days.