[A comparison of fluorescent methods of determining the concentration of vitamin B2 in blood].

Three methods of riboflavin assay in the human blood were comparatively studied. It has been found that firmly-bound flavin forms present in erythrocytes inhibit their complete transmission into the riboflavin form. Low specificity of the method using riboflavin fluorescence suppression with dithionite has been proved. Dithionite capacity for suppressing fluorescence of riboflavin-like substances significantly rises detectable levels. The use of riboflavin-binding protein permits one to determine only free riboflavin form. It has been established that the lumiflavin method is most reliable and specific for riboflavin assay in erythrocytes.