ADA (Any Body Fluids, PUS & Blood) in Dehradun

What is a ADA (Any Body Fluids, PUS & Blood)?

Adenosine deaminase is an enzyme concentrated in activated T lymphocytes, and measuring it in body fluid rather than blood is where the test genuinely earns its place. Tuberculous infection of the pleura, peritoneum, pericardium or meninges produces an intense lymphocyte response in that cavity, and the ADA level rises accordingly. This matters because bacteriological confirmation from these fluids is notoriously difficult: smear microscopy is almost always negative, cultures take weeks and are frequently negative even in confirmed disease, and obtaining tissue may require an invasive procedure such as pleural biopsy. A raised ADA in pleural fluid with a lymphocyte-predominant, protein-rich effusion has good diagnostic value for tuberculous pleurisy in a high-prevalence country like India, and similar reasoning applies to ascitic fluid in tuberculous peritonitis. It is not infallible. Empyema, lymphoma, rheumatoid pleurisy and some other conditions also raise it, so the value is read alongside the cell count, differential, protein, glucose and the clinical picture rather than on its own.

Why take this test?

ADA on fluid is advised whenever a pleural effusion or ascites has been tapped and tuberculosis is a possibility, which in India is most of the time in an effusion that is lymphocyte-predominant and protein-rich without an obvious alternative explanation. It is used in suspected tuberculous pericarditis and in cerebrospinal fluid where tuberculous meningitis is being considered, although in the latter case molecular testing carries more weight and treatment is often started on suspicion because delay is dangerous. It is requested at the same time as the fluid's routine analysis, its cell count and differential, protein, glucose and, importantly, a molecular test for tuberculosis DNA and a culture, since the combination is what builds the diagnosis. The fluid must be obtained by a doctor through a tap or lumbar puncture, so this is arranged clinically rather than ordered independently.

• A lymphocyte-predominant, protein-rich pleural effusion
• Ascites where tuberculous peritonitis is a possibility
• Suspected tuberculous pericarditis
• Cerebrospinal fluid where tuberculous meningitis is considered
• Alongside fluid cell count, protein, glucose and molecular testing
• Where bacteriological confirmation is difficult to obtain

FAQs: ADA (Any Body Fluids, PUS & Blood) in Dehradun