Mycobacterium tuberculosis (MTB) antibody screening in whole blood by immunoassay

What This Test Measures

The test detects specific antibodies produced by your immune system in response to *Mycobacterium tuberculosis*. These antibodies can indicate exposure to the bacteria, which may have occurred through infection or vaccination (e.g., BCG vaccine). The presence of these antibodies does not always mean you currently have active TB, but it can signal a need for further evaluation.

Why It’s Done

Your healthcare provider may order this test if you have symptoms suggestive of TB (e.g., persistent cough, fever, weight loss), live in an area with higher TB rates, or have risk factors like weakened immunity, recent travel to high-risk regions, or contact with someone diagnosed with TB.

What to Expect

The test involves drawing blood from a vein in your arm. The sample is processed to detect antibodies using an immunoassay method. Results are typically available within 24–72 hours, depending on lab protocols.

Interpretation and Next Steps

A positive result suggests possible exposure to *M. tuberculosis*, but it does not confirm active TB. Follow-up may include additional tests (e.g., TB skin test, sputum culture) or imaging to assess risk or infection status. A negative result means no detectable antibodies at this time, but exposure cannot be ruled out without further testing.