Nitric Oxide Fluorometric Assay Kit (Cat# K252-200) provides an accurate and convenient measurement of total nitrate/nitrite concentration in a simple two-step process. The first step is the conversion of nitrate to nitrite utilizing nitrate reductase. The second step involves addition of DAN followed by NaOH, which converts nitrite into a fluorescent compound. Measurement of the fluorescence of this compound accurately determines the total nitric oxide production. The kit has been validated in culture media, plasma, and tissue homogenates. Some sample purification from these sources may be necessary.