The kit is designed for nitrite determination in biological samples.Background: The overproduction of nitric oxide may lead to oxidative and nitrosative stress. It has been demonstrated that they enhance the development of a variety of diseases, as well as the ageing process.Regarding nitrosative stress, high levels of iNOS have been found in various inflammatory diseases such as arthritis and obesity, and increased levels of NO have been also associated to other cardiovascular diseases. Bioquochem Nitrite Determination Assay Kit is recommended for the determination of nitrite. The assay described here measures the nitrite anion. The detection is based of spectrophotometric properties of diazonium compound (λmax= 540 nm) obtained after several steps of nitrite reaction with sulfanilamide.