Broncho Alveolar Lavage for AFB Smear/ZN Stain

Specimen Required

Broncho Alveolar

Fasting Required

Purpose of the Test

The bronchoalveolar lavage (BAL) AFB smear/ZN stain test is used to detect the presence of acid-fast bacilli (AFB) in a sample of fluid that is collected from the lungs through a bronchoscopy procedure. AFB are a type of bacteria that can cause tuberculosis or other infections in the lungs.

When this test is required

The test may be requested if a patient has a suspected or confirmed case of TB or if they have been exposed to someone with the disease. It may also be used to diagnose other types of mycobacterial infections, such as Mycobacterium avium complex (MAC) or Mycobacterium kansasii.

What the Test Detects

During the test, a bronchoscope is inserted through the mouth or nose, and a small amount of sterile saline is used to wash out a portion of the lung (alveoli) and collect the fluid sample. This sample is then analyzed for the presence of AFB using a staining method called ZN staining.

Preparation for the Test

Before the procedure, the healthcare provider may give instructions on fasting or avoiding certain medications. The person may also be given a sedative to help them relax during the procedure. It is important to follow any instructions given by the healthcare provider to ensure a successful and safe procedure.

Sample Requirements

The BAL procedure involves passing a bronchoscope through the mouth or nose and into the lungs to collect a sample of fluid from the alveoli (small air sacs in the lungs). The fluid is collected by washing the lung tissue with saline solution, which is then collected and sent to the laboratory for testing.

Additional Notes

It is important to note that a negative AFB smear/ZN stain does not rule out TB or other mycobacterial infections, and additional testing may be necessary. Other tests that may be used in conjunction with BAL for AFB smear/ZN stain include culture, nucleic acid amplification testing (NAAT), and chest X-ray.

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