Lactate Dehydrogenase Assay Kits provide both fluorescence and absorbance-based method for detecting either L-lactate dehydrogenase (L-LDH) or D-lactate dehydrogenase (DLDH) in biological samples such as serum, plasma, urine, as well as in cell culture samples. In the enzyme coupled assay, LDH is proportionally related to the concentration of NADH that is specifically monitored by a chromogenic NADH sensor. This assay kit is specific for D-LDH. The absorption signal can be read by an absorption microplate reader at ~575 nm or at the absorbance ratio of ~570 nm to ~605 nm (A575nm/A605nm) to increase assay sensitivity. With this colorimetric D-lactate Dehydrogenase Assay Kit, we were able to detect as little as mU/mL DLDH in a 100 μL reaction volume. It is robust, and can be readily adapted for a wide variety of applications that require the measurement of D-LDH.