Heme is one important member of the porphyrin family. It is synthesized in both mitochondria and cytoplasm, and is a key prosthetic group for various essential proteins such as hemoglobin, cytochromes, catalases and peroxidases. Heme determination is widely practiced by researchers of various blood diseases. Simple, direct and automation-ready procedures for measuring heme concentration are becoming popular in Research and Drug Discovery. This Heme Assay Kit is based on an improved aqueous alkaline solution Method, in which the heme is converted into a uniform colored form. The intensity of color, measured at 400 nm, is directly proportional to the heme concentration in the sample. The optimized formulation substantially reduces interference by substances in the raw samples and exhibits high sensitivity.