Analysis of Hemoglobin A1c from Dried Blood Spot Samples with the Tina-quant(R) II Immunoturbidimetric Method

Hemoglobin A1c (HbA1c) has been endorsed as a tool for the diagnosis of diabetes. This test requires instrumentation that may not be available in underdeveloped areas. Dried blood spot (DBS) samples collected by finger stick procedures offer a mechanism to transport samples to laboratories that do measure HbA1c.Whole blood (ethylenediaminetetraacetic acid) was applied to Ahlstrom 226 filter paper. These DBS samples were compared to whole blood samples using the Roche Tina-quant II immunoturbidometric assay. Hemoglobin A1c stability on DBS was assessed at three temperatures-4, 25, and 40 degrees C-for up to 9 days. A 44-day study was also done for DBS at 20-25 degrees C.The Tina-quant II DBS method showed excellent agreement with whole blood HbA1c results (r(2) = 0.99) with a slight positive mean bias of 0.08 +/- 0.04% HbA1c (95% confidence interval). The variation in HbA1c on DBS samples subjected to different temperatures and times did not exceed 5.6%.Dried blood spot samples represent an alternative to whole blood for HbA1c by measurement when transporting whole blood is not feasible.