Mycobacterium tuberculosis antigen detection (serum/plasma)

What This Test Measures

The test detects either *Mycobacterium tuberculosis* antigens (directly from the bacterium) or antibodies (immune response to TB). Antigen tests are often used for early detection, while antibody tests may indicate past or ongoing infection.

Why It’s Ordered

Your healthcare provider may order this test if you have symptoms of TB (e.g., persistent cough, fever, weight loss), a history of TB exposure, or if you’re at higher risk (e.g., immunocompromised, recent travelers). Antigen tests are sometimes used in high-risk settings like hospitals.

Sample Collection and Preparation

Blood is drawn from a vein, and the sample is processed into serum or plasma. The test may use immunoassay methods (e.g., chemiluminescent immunoassay) to detect the target molecules.

Test Limitations

Results can be affected by recent TB exposure, immune status, or test sensitivity. False negatives may occur in early or latent infection, while false positives are rare but possible.