Labile glycated hemoglobin: an underestimated laboratory marker of short term glycemia
Joris Delanghe, Stijn Lambrecht, Tom Fiers, Marijn M. Speeckaert
Abstract
Abstract Objectives Diabetes mellitus is a major public health problem. Hemoglobin A 1c (HbA 1c ) is a key laboratory parameter in the management of diabetes patients. However, in diabetes monitoring, interpretation of HbA 1c results is hampered by the important interindividual variation in red blood cell (RBC) life span. Furthermore, HbA 1c only slowly responds to changes in glucose metabolism. Besides HbA 1c , there exists a labile HbA 1c fraction (l-HbA 1c ), exhibiting much faster kinetics. As both HbA 1c and l-HbA 1c are measured by modern standard chromatography, we explored the possibilities of using the l-HbA 1c fraction for monitoring glycemia. Methods l-HbA 1c and HbA 1c fractions were simultaneously assayed on a Tosoh G8 analyzer and expressed as %. l-HbA 1c results were compared with serum glucose and HbA 1c . Concomitantly, RBC distribution width (RDW) was determined on a Sysmex SN analyzer as a marker for erythrocyte life span. Results l-HbA 1c could be measured with between-run coefficient of variations (CVs) between 2.2 and 2.3%. l-HbA 1c correlated with both glycemia (r=0.80) and HbA 1c results (r=0.73). In a multiple regression model (r 2 =0.752), glycemia and HbA 1c were the most determining factors. To a lesser extent, RDW correlated with l-HbA 1c (r=0.158). Furthermore, the l-HbA 1c /HbA 1c ratio weakly positively correlated with RDW (r=0.247). Conclusions L-HBA 1c represents an additional marker for monitoring the rapid occurrence of glycemic disorders that escape detection when using only HbA 1c and blood glucose. RDW can be used as an indicator of atypical RBCs life span, in which the l-HbA 1c fraction may be helpful.