[Incidence of sample storage temperature on HbA 1c determination by high performance liquid chromatography method]

We have evaluated the conservation prior to HbA(1c) determination of three whole blood samples stored at -80 degrees C, -20 degrees C, 4 degrees C and 20 degrees C, for a maximal duration of one year. HbA(1c) was measured by an ion-exchange high performance liquid chromatography (HPLC) method (Variant II). We have analyzed the HbA(1c) value and the quality of the chromatographic separation for each sample. Storage of whole blood samples at -80 degrees C is good for at least one year. Storage at 4 degrees C is correct for two weeks, without major sample degradation. A more important and earlier degradation occurs at -20 degrees C. The conservation at 20 degrees C (room temperature) is very short. In conclusion, the temperatures of 4 and -80 degrees C are of interest for whole blood storage before HbA(1c) measurement, respectively for short and long term conservations. The temperatures of 20 and -20 degrees C are not recommended.