Abstract
A specific medical examination in Kumamoto Prefecture demonstrated that the rates of examinees with HbA1c levels above the reference level (5.6%) significantly varied among regions. To find the cause and take corrective action, differences in the measurement results due to instruments and reagents were investigated. Blood samples were taken from 20 patients from whom informed consent was obtained. JCCRM411-2 was used as a reference standard. HbA1c level was measured for each sample using HPLC, turbidimetric immunoassay, and an enzymatic method. The measurements demonstrated a maximum difference of 0.3% in blood samples from patients with a HbA1c level of 5.6% among the methods. The measurements were 0.2 and 0.1% higher by the HPLC and enzymatic methods than that of the reference standard, respectively, and closely corresponded to those by the turbidimetric immunoassay. Different instruments and reagents may have caused the differences in measured HbA1c levels. To solve this problem, efforts should be immediately made to standardize the HbA1c measurement methods.
