Preanalytical and analytical considerations for measuring nitric oxide metabolites in serum or plasma using the Griess method.

Nitric oxide (NO) plays numerous important roles in many biological systems and, therefore, research in this field, which impacts all aspects of biology and medicine, especially NO measurement, is steadily increasing. Nitric oxide has a short biological half-life, making its direct determination in vivo difficult. Therefore, currently assessment of nitrite and nitrate (NOx) in biological fluids seems to be the most suitable method to assess NO synthesis in vivo. The most frequently used method of NOx analysis is based on the Griess reaction. Although measurement of NOx by the Griess assay is simple and cheap, the accurate determination of plasma/serum concentrations of nitrate/ nitrite using the Griess assay is prone to interferences and can be influenced by several factors. The aim of this study was to overview preanalytical and analytical considerations for measuring NOx in serum or plasma using the Griess assay.