Coefficient of variation for hemoglobin A1c results that are traceable to national glycohemoglobin standardization program must be distinguished from coefficient of variation for results traceable to International Federation of Clinical Chemistry and Laboratory Medicine.

摘要

Dear Editor:Imprecision of measurement is often expressed as the coefficient of variation (CV%). It is calculated by dividing the SD by the mean of the data set and then multiplying by 100. The CV% is often used for the comparison of different assays for a certain quantity, such as hemoglobin Ale (HbA_1c). (Imprecision expressed as CV% has meaning only for ratio scale results. For differential scale results, such as temperature expressed as "Cor "F, the CV% has no meaning.) For the moment we have two different types of HbA_1c results, expressed either with the old National Glycohemoglobin Standardization Program (NGSP), the organization in charge of the standardization used for the Diabetes Control and Complications Trial.