Diagnostic significance of immunoglobulins and adenosine deaminase in pleural effusion.

ABSTRACT

OBJECTIVES: 1) To evaluate the diagnostic significance of ELISA for detection of antibodies to antigen A60 of Mycobacterium tuberculosis and adenosine deaminase (ADA) in patients with pleural effusion without prior history of tuberculosis, 2) To study the importance of the above tests in patients with HIV infection and pleural effusion. METHOD: Eighty one patients with pleural effusion were studied. In addition to diagnostic paracentesis and pleural biopsy, pleural fluid specific IgG, IgM, IgA against antigen A60 and fluid ADA were estimated. HIV testing (ELISA) was done in all patients. RESULTS: Out of 81 patients, 13 were HIV positive. IgG anti A60 had a sensitivity and specificity of 90.71% and 33.33% respectively. The combination of IgG and IgM had a sensitivity and specificity of 96.3% and 55.55% respectively. IgA alone or in combination did not offer any diagnostic advantage. ADA had a sensitivity and specificity of 76% and 60% respectively. In presence of HIV infection, antibodies against A60 had a sensitivity of 76.92% and ADA had a sensitivity of 61.54%. CONCLUSIONS: In patients with pleural effusion, immunoglobulins against antigen A60 have a limited diagnostic role with high false positive rates. Co infection with HIV further reduces the value of above diagnostic tests.