ADA is an enzyme involved in purine metabolism, converting adenosine to inosine.

It plays a key role in lymphocyte proliferation and differentiation.

Elevated ADA levels are associated with tuberculosis, especially in pleural effusion, but serum ADA can also rise in other infections and immune disorders.

Clinical uses include:

Supporting diagnosis of tuberculosis (though pleural fluid ADA is more specific).

Evaluating immune system disorders.

Monitoring certain hematological malignancies and chronic infections.

The test is performed using a blood sample.

Analyte: ADA enzyme activity in serum.

Normal Range: ~0 – 30 U/L (varies slightly by lab).

Abnormal Findings:

High ADA: May indicate tuberculosis, other bacterial infections, autoimmune diseases, or certain cancers (e.g., lymphoma, leukemia).

Low ADA: Rare, but may occur in severe immunodeficiency.

Clinical Use:

Provides supportive evidence for TB diagnosis when correlated with clinical findings.

Helps assess immune activation in infectious and autoimmune conditions.

Guides further investigations in suspected hematological disorders.