Sputum for AFB Smear/ZN Stain

Specimen Required

SPUTUM

Fasting Required

Purpose of the Test

A sputum acid-fast bacilli (AFB) smear/Ziehl-Neelsen (ZN) stain is a test used to detect the presence of acid-fast bacilli in a sputum sample. This can help diagnose tuberculosis (TB) and other infections caused by Mycobacterium species.

When this test is required

This test may be requested when a patient has symptoms of a respiratory infection and TB is suspected. It may also be requested to monitor the effectiveness of treatment for a TB infection.

What the Test Detects

The test involves a microscopic examination of the sputum sample to detect the presence of acid-fast bacilli. The AFB smear/ZN stain is a preliminary test that can provide quick results, but it is not as sensitive as other diagnostic tests for TB, such as culture and PCR.

Preparation for the Test

Patients may be advised to drink plenty of fluids to help loosen the sputum and make it easier to cough up. They may also be advised to avoid smoking or exposure to secondhand smoke, which can irritate the lungs and make it more difficult to produce a sputum sample.

Sample Requirements

The test requires a sputum sample, which is usually collected in the morning before eating or drinking anything. The patient may be instructed to rinse their mouth with water prior to collecting the sample to minimize contamination with oral bacteria.

Additional Notes

It is important to follow the healthcare provider’s instructions for collecting and handling the sputum sample to ensure accurate test results. Patients should also inform their healthcare provider of any medications they are taking, as some antibiotics and other medications can interfere with the test results.

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