For quantitative determination of fumarate and drug effects on its metabolism. Key Features: Fast and sensitive. Use of 20 µ L sample. Linear detection range 0.005 to 2 mM fumarate in 96-well plate assay. Convenient. The procedure involves adding a single working reagent, and reading the optical density after 30 minutes. Room temperature assay. No 37° C heater is needed. High-throughput. Can be readily automated as a high-throughput 96-well plate assay for thousands of samples per day. Method: OD565nm. Samples: Food, beverage and other biological samples (e.g. cell lysate, tissue homogenate, serum) . Species: All. Procedure: Assay takes 30 min. Kit size: 100 tests. Detection limit: 5 µ M.