PromoCell’s Nitric Oxide Assay Kit II provides an accurate and convenient tool for total nitrate/nitrite concentration determination in a simple two-step process that can be used as a quantitative measure of NO production. The first step is the conversion of nitrate to nitrite utilizing nitrate reductase. The second step involves the addition of the fluorometric reagent DAN followed by NaOH, which converts nitrite into a fluorescent compound. Measurement of the fluorescent compound reaction product accurately determines the total nitric oxide production. The Fluorometric Assay Kit has been validated in cell culture media, plasma, and tissue homogenates.