Definitions for "Acid-fast bacilli"
Microorganisms that are distinguished by their retention of specific stains even after being rinsed with an acid solution. The majority of AFB in patient specimens are mycobacteria, including species other than Mycobacterium tuberculosis complex. A positive nucleic acid amplification (NAA) or culture result is needed for confirmation of M. tuberculosis complex. The relative concentration of AFB per unit area on a slide (the smear grade) is associated with infectiousness.
Organisms that retain certain stains, even after being washed with acid alcohol. Most acid-fast organisms are mycobacteria. When seen on a stained smear of sputum or other clinical specimen, a diagnosis of tuberculosis should be considered.
mycobacteria that stay stained even after they have been washed in an acid solution; may be detected under a microscope in a stained smear