HPLC analysis of HbA1c in dried blood spot samples (DBS): a reliable future for diabetes monitoring.

To simplify collection and transport of blood for HbA1c measuring, we have studied the use of a special paper that absorbs a defined volume of capillary blood and quickly dries it (dried blood-spot, DBS). The DBS can be sent to a central laboratory using regular postal service and without temperature control. This system differs greatly from other proposed DBS methods for HbA1c because it overcomes the haemoglobin alterations during the drying and storing processes, that otherwise make this analysis unreliable. We have developed a special treatment of the paper before collection that stabilises the HbA1c molecule excellently in dried blood samples, allowing accurate HPLC analysis even two weeks after collection. This method has been applied in a "blind" study in which HbA1c values determined in 97 DBS coming from an hospital diabetes care centre were compared with those obtained from parallel venous blood samples.