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Advanced Diagnostic Laboratories

Smear, Culture and Identification of Acid Fast Bacilli

Test Code



This test includes AFB smear, culture, and organism identification from a clinical specimen. 

The AFB smear is a direct fluorescent stain from the specimen and can be used to quickly establish the presence of mycobacteria. The AFB culture is the inoculation of a clinical specimen onto multiple media types followed by monitoring for six weeks. Growth of any AFB (i.e. mycobacteria) or partially acid fast organisms (e.g. aerobic actinomycetes) is identified.  Identification will occur to the greatest extent possible, which is usually to the species level but can be to the subspecies level for some organisms (e.g. Mycobacterium abscessus subsp. abscessus).

This test is typically used when there is low risk of tuberculosis since no direct test for Mycobacterium tuberculosis is performed from the specimen (although it is fully identified if it is seen). If there is an unknown or higher risk of M. tuberculosis infection, order AFB1.