Acid-Fast Bacillus Test
The AFB test is used to detect the presence of Mycobacterium species, such as the bacteria that cause tuberculosis (TB). A sample (usually sputum, urine, or tissue) is stained using the Ziehl-Neelsen method, which allows for the identification of acid-fast bacilli under a microscope. A positive result suggests a current or past infection with TB or other mycobacterial diseases.