Determn. of fructosamine (I) in body fluid comprises treating the sample with (a) pH 9-12 buffer; (b) colour-forming cpd. (II); (c) uricase and (d) at least one detergent. The mixt. is incubated at 20-40 deg.C and the change in extinction over time is measured, after 5 mins. reaction at the earliest. A reagent contg. components (a)-(d) plus an oxidative enzyme is itself claimed. A peroxidatively-active enzyme, esp. peroxidase, is included and the mixt. is incubated at 25-37 deg.C, with measurements taken 5-15 mins. after reagent addn.
