TB ADENOSINE DEAMINASE; ADA (NHC)

The TB Adenosine Deaminase (ADA) (NHC) test measures the level of Adenosine Deaminase (ADA), an enzyme involved in the body’s immune response. Elevated ADA levels in body fluids such as pleural fluid, ascitic fluid, or cerebrospinal fluid (CSF) may support the diagnosis of tuberculosis (TB), particularly extrapulmonary TB. ADA testing may also be useful in the evaluation of certain immune disorders, including Severe Combined Immunodeficiency Syndrome (SCID), and in selected cases of hemolytic anemia of unknown cause. However, ADA levels should always be interpreted along with clinical findings and other laboratory investigations, as elevated levels are not specific to tuberculosis.

The test can be performed on serum, plasma, or body fluids such as pleural fluid, ascitic fluid, or CSF. It is commonly recommended when tuberculosis involving body cavities is suspected or when additional diagnostic support is required. Proper specimen collection and transport are essential, and hemolysed samples are not acceptable. The TB ADA test serves as a valuable adjunctive investigation that helps clinicians assess the likelihood of tuberculosis, supports timely diagnosis, and assists in planning appropriate patient management.