Evaluation and performance characteristics of a novel ELISA using monoclonal antibody to glycated albumin.

To evaluate the clinical utility of a highly specific monoclonal antibody directed against the glycated epitopes residing in human albumin, we developed an ELISA using this antibody to measure glycated albumin in plasma samples from nondiabetic and diabetic individuals. The assay is predicated on the ability of immobilized monoclonal antibody to distinguish glycated albumin from all other plasma proteins, followed by detection and quantitation of the bound glycoalbumin with an enzyme-conjugated second antibody directed against human albumin. The relative percent concentration of glycated albumin in a sample is then determined by dividing the microgram glycated albumin in the sample by the total microgram albumin in the sample. The mean glycoalbumin level in samples from 12 non-diabetic subjects was 2.4% +/- 0.22% (mean +/- SD). In samples from 30 diabetic subjects, glycated albumin levels ranged from 1.6% to 14.9%, and individual values correlated positively and significantly with glycohemoglobin levels measured in simultaneously collected red cells. The intra- and inter-assay coefficients of variation of the method were 6.8 and 7.4%, respectively. The findings indicate that this ELISA allows sensitive, specific and reproducible measurement of glycoalbumin, and provides a clinically relevant objective parameter of integrated glycemic control.