[Interference of labile glycated hemoglobin on HbA(1c) assay by a high pressure liquid chromatography method].

HbA(1c) assay by high pressure liquid chromatography remains submitted to interferences, among which that of labile HbA(1c) in 1 to 2% of samples. We have evaluated the interference of labile HbA(1c) on HbA(1c) assay using Variant II analyzer (Biorad), by in vitro formation of labile glycated haemoglobin and by evaluation of two protocols of elimination of labile HbA(1c) (wash and incubation of red blood cells in saline solution, or incubation in the wash/dilution solution of the analyzer). Levels of labile HbA(1c) higher than 4.5 % lead to underestimation of HbA(1c). The different protocols tested proved efficient and were adapted to routine conditions. The fastest method is the incubation of red blood cells in the wash/dilution solution for at least two hours, or more if labile fraction is unusually high.