Investigation and validation of the affinity chromatography method for measuring glycated albumin in serum and urine

Affinity chromatography on m-aminophenyl boronate columns together with albumin measurement by radioimmunoassay has been validated as a method for determining glycated albumin in serum and urine. Optimisation of sample volume and of elution buffer composition and volume ensured reproducibility of results. Fructosamine assay confirmed the absence of glycated albumin species from the non-glycated fraction. It was possible to elute the glycated fraction from the affinity columns with Tris or glycine which do not contain 1,2 diols but have similar functional groups. Column affinity was, therefore, not specific for glycated protein moieties. Inhibition of binding by glucose, and other small molecules in urine, necessitated ultrafiltration or dialysis of samples before analysis. Reference ranges for glycated albumin in non-diabetic subjects were 0.6-1.8% in serum and 0.9-2.6% in urine. In patients with diabetes mellitus, glycated albumin ranged from 1.4-10.9% in serum and from 1.5-12.5% in urine.