The effect of haematocrit on reagent strip tests for glucose

Four blood glucose reagent strips (BM-Test 1-44, Glucostix, Hypoguard GA, and Exactech), used in conjunction with measuring devices produced by the same manufacturer, were investigated with respect to the influence of haematocrit. The erythrocytes and plasma of fresh blood samples were separated, then remixed in different proportions to achieve a range of haematocrit values and the resulting specimens subjected to glucose assay. All the strip tests showed some influence of haematocrit, low haematocrits producing higher glucose results and vice versa, but some were much more affected than others. The Hypoguard GA was most affected and the BM-Test 1-44 least. In the worst case, glucose results differed by 49% from one end of the normal adult haematocrit range to the other.