Glycosylated hemoglobin measured by affinity chromatography: micro-sample collection and room-temperature storage

Under proper conditions, whole blood can be stored at room temperature for as long as 21 days before measurement of glycosylated hemoglobin by affinity chromatography. Whole blood (anticoagulated with EDTA or heparin) was placed in capillary tubes, which were then sealed at both ends and stored at room temperature. Just before assay, whole blood was rinsed from the tubes and diluted 10-fold with water. Samples of each patient's blood were assayed as whole-blood hemolysates by affinity chromatography after zero, seven, 14, and 21 days of storage. Values for glycosylated hemoglobin did not change over 21 days of storage and values for each storage day correlated well (r = 0.97, p less than .0001) with hemoglobin A1C measured in fresh erythrocyte hemolysates by "high-performance" liquid ion-exchange chromatography.