Measuring flavin mononucleotide concentrations in whole blood, red cell based or acellular perfusate samples by fluorescence spectrometry

Abstract Flavin mononucleotide (FMN) is non-covalently bound to complex I of the mitochondrial respiratory chain. During ischemia-reperfusion injury, reduced FMN is released from complex I, leaving the complex impaired. In literature, FMN measured during ex situ organ perfusion has been considered as a biomarker for organ graft quality. With this protocol the FMN concentrations in perfusate samples taken during organ perfusion can be estimated quickly and easily by fluorescence spectrometry. The use of non-binding plates is essential. A fresh standard curve using riboflavin 5'-monophosphate sodium salt hydrate must be prepared every day. To quantitatively compare sample concentrations between different plates, it is advisable to include an internal standard. This internal standard is best prepared by pooling samples from experiments that use the same perfusate composition. This assay will work for samples acquired from whole blood, red cell based solutions or acellular solutions.