SUMMARY.A colorimetric method for the measurement of whole-blood glycosylation (WBG), glycosylated haemoglobin in red blood cells (GHb), glycosylated plasma protein (GPP) and dried-blood glycosylation (DBG) is described which is rapid, inexpensive and precise. GHb correlated well with HbA\ measured by cation-exchange chromatography and was also correlated with WBG, DBG and GPP. DBG, which showed good correlation with GHb, could be measured on several drops of blood dried on filter paper treated with glucose oxidase. Filter papers are posted to the laboratory prior to clinic visits, and by having the DBG result available more rational diabetic management is possible. For DBG, the intra-and inter-assay coefficient of variation at three levels is less than 6%. Reference values in non-diabetic children have been calculated and are compared with values obtained in 'good' clinical diabetic control and in 'fair' control. The filter-paper assay DBG method has a high degree of patient acceptance. Glycosylated haemoglobin was first described in the blood of diabetic patients in 1967 by Rahbar. I It was designated HhAj.; being the third of five minor haemoglobin components eluted from .a Bio-Rex 70 column before the major portion of haemoglobin A o .2 Further studies have revealed extra sites of glycosylation other than the N-terminal amino groups of valine on the~-chains as found in HbA 1c ' The glycosylation of haemoglobin can now be described as the post-translational non-enzymatic condensation between the aldehyde of glucose and both N-terminal amino groups of a-and -chains and E-amino groups of lysine residues of a-and f3-chains.3 Glucose is first bound in a reversible Schiff-base (aldimine) linkage; some of this labile glycosylated haemoglobin undergoes an irreversible Amadori rearrangement to a stable ketoamine (amino-1-deoxyfructose)form."

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