[Diurnal variations of fructosamine in patients with type II diabetes mellitus]

During the last years fructosamine has been presented as a measurement of diabetic long term control, particularly a shorter half life of fructosamine was seen as an advantage over HbAlc (half life of fructosamine: 16 days, half life of HbAlc: 28 days). Due to diurnal variations of fructosamine levels especially in dependence of variations of the albumin-and protein concentrations the interpretation of this parameter was somewhat limited. Recently a new colorimetric fructosamine-assay was developed. We investigated the diurnal variations of fructosamine in 28 patients with type II diabetes. Fructosamine, glucose, albumin, total protein and creatinine were measured at the times towards 3, 6, 9, 12 a.m. and 3, 6, 9, and 12 p.m. In relation to the 6 a.m. fructosamine value (= 100%) the fructosamine levels showed a daily variation from -4% at 3 a.m. to +11% at 9 a.m. Correcting fructosamine levels with total protein or with albumin reduced the variations to -1% to +6% or -3% to +9%. Daily profiles of the new fructosamine assay show a daily variation which can be minimized by correcting with protein-or with albumin concentrations. For clinical routine the daily variations especially of the corrected fructosamine levels are neglectible.