The full form of AFB is Acid-Fast Bacillus.
AFB refers to a group of bacteria that possess a unique cell wall property, making them resistant to decolorization by acids during staining procedures. This characteristic is termed "acid-fastness." The most well-known AFB is Mycobacterium tuberculosis, the causative agent of tuberculosis (TB). However, other mycobacteria, such as Mycobacterium leprae (causing leprosy) and certain non-tuberculous mycobacteria (NTM), are also acid-fast.
AFB tests are crucial in diagnosing mycobacterial infections. These tests involve staining sputum or other clinical samples with a dye (usually Ziehl-Neelsen or Kinyoun stain) and then examining them under a microscope. If acid-fast bacilli are present, they will retain the dye even after being treated with an acidic solution, appearing as bright red or pink rods against a blue background.
Therefore, when you see "AFB" in a medical context, it almost always refers to Acid-Fast Bacillus and its significance in diagnosing mycobacterial diseases.
