It can be used for quantitative determination of homocysteine in human serum samples in vitro by medical institutions for auxiliary diagnosis. Homocysteine (HCY) level is closely related to cardiovascular disease and is an important risk factor for cardiovascular disease. In addition, increased HCY can also cause birth defect diseases such as neural tube malformation and congenital malformation. It is related to vascular disease, neural tube malformation, preeclampsia, Parkinson's disease, slow fetal growth, chronic renal failure and other diseases and the influence of certain drugs and tumors.

After the binding HCY was reduced to free HCY, the free HCY reacted with serine to form l-thione (CYS) under the catalysis of thione beta-synthase (CBS). L-thione ether (CYS) generates HCY, pyruvate and NH3 catalyzed by thione beta-lyase (CBL). The pyruvate generated by this cyclic reaction, under the action of lactate dehydrogenase (LDH), causes the conversion of beta-nadh to beta-nad +, and the change in absorbance at 340nm is proportional to the HCY concentration in the sample.