This microplate kit is used to determine the amount of PDH in a human, bovine, mouse, or rat sample with speed and simplicity. The PDH enzyme is immunocaptured by an anti-PDH mAb immobilized in microplate wells, and the amount of PDH captured is determined by adding a second PDH specific antibody conjugated with alkaline phosphatase. This phosphatase changes the substrate pNPP from colorless to yellow (OD 405 nm) in a time dependent manner proportional to the amount of PDH protein captured in the wells. Included for performance in the quantity assay are buffer, detergent, antibodies, substrates, and a 96-well microplate with monoclonal antibody pre-bound to the wells of the plate, allowing for a stream-lined assay.