Lactate dehydrogenase (LDH) is an oxidoreductase enzyme that catalyzes the interconversion of pyruvate and lactate. LDH is present in cytosol of a wide variety of organisms, including animals and plants. Cells release LDH into the bloodstream after tissue damage or red blood cell hemolysis. Since LDH is a fairly stable enzyme, it has been widely used to evaluate the presence of damage and toxicity of tissue and cells. Quantification of LDH has a broad range of applications. LDH is also elevated in certain pathological conditions such as cancer. This Amplite Lactate Dehydrogenase Assay Kit provides a absoption-based method for detecting L-lactate dehydrogenase (L-LDH) 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 assays is specific for L-LDH. The absorption signal can be read  by an absorption microplate reader at ~575 nm. With this colorimetric Amplite L-lactate Dehydrogenase Assay Kit, we were able to detect as little as 3 mU/mL L-lactate dehydrogenase in a 100 L reaction volume.