Glycation gap: An additional tool for glycometabolic monitoring

The determination of glycated albumin (GA) has been suggested as an additional parameter having an independent added value respect to that of HbA_1c. The determination of glycation gap (gg) has also been proposed, but few studies have addressed its potential impact in the routine evaluation of glycometabolic control.

A total of 157 subjects presenting normal whole blood cell count, no hemoglobin variants, normal creatinine levels and serum protein electrophoresis patterns were studied. In a second phase, a total of 205 subjects with no restrictions as those of the first phase study, were analyzed. HbA_1cwas measured by capillary electrophoresis, glycated albumin by an enzymatic method and their gg were then calculated.

The correlation between HbA_1c and GA for the subjects of phase 1 was strong (r=0.8927) and significant correlation between gg and age was remarked (r=0.4486). We found 17.1% of phase 2 subjects with gg falling outside the 95% prediction intervals. Various clinical conditions seemed to affect these subjects, in our experience mostly often related to impaired renal function.

The glycation gap may be useful to alert clinicians about patients under unstable glycemic control or when various pre-analytical conditions my affect the reliability of the measurement of GA or HbA_1c.