The test is used to diagnose tuberculosis (TB) and other infections caused by acid-fast bacteria.
When this test is required
The test may be requested when a person has symptoms of TB or when a person has been exposed to someone with TB.
What the Test Detects
The test looks for the presence of acid-fast bacteria in a sample using special staining techniques.
Preparation for the Test
No special preparation is required for the test.
Sample Requirements
The sample required for this test is usually sputum, but other bodily fluids such as blood, urine, or cerebrospinal fluid (CSF) may be used as well.
Additional Notes
The AFB smear/ZN stain is a preliminary test and may need to be confirmed with a culture or NAAT. It is also important to note that other conditions, such as non-tuberculous mycobacterial infections, can also cause a positive result.
