ADA and HIV infectious disease: Definitive diagnosis of tuberculous etiology is challenging because studies have shown the yield from direct smear examination of pericardial fluid to be as low as 2%9; culture of pericardial fluid is positive in 38–56% of cases.9,10 Other indirect methods used to support TB diagnosis, such as adenosine deaminase levels in pericardial fluid, have the limitation of lower sensitivity in persons with advanced HIV infection.11 All diagnostic studies have the common problem of the lack of a definitive gold standard.