Adenosine Deaminase(AD) Determination Reagent(Peroxidase method) is an in vitro diagnostic quantitative test kit. Adenosine Deaminase, Pleural Fluid - An elevated level of AD in human serum, plasma or select body fluids is used as a surrogate marker for inflammation or infectious disease. In CSF, pleural effusions, and pericardial fluid in particular, elevated AD activity has been shown to be associated with tubercular lesions.