HbA_1c is a glycated hemoglobin which was used to assess the glucose level of diabetes mellitus patients for the previous 1-2 month. The standard method for the measurement of HbA_1c requires EDTA blood. Almost all physicians requesting HbA_1c also include a blood glucose test in the same requisition test panels that requires a NaF blood sample. From these requisition test panels, an absence of either an EDTA blood or NaF blood sample to complete the requirement for the determination of both HbA_1c and blood glucose is common. Thus, the main aim of this research is to attempt to introduce the use of NaF blood in order to determine the amount of both HbA_1c and glucose. A comparison of the HbA_1c values obtained from using the EDTA blood and the NaF blood was established. A total of 212 patient blood samples was collected and both EDTA blood and NaF blood were analyzed by the Hitachi 717 automatic analyzer using the Turbid metric Inhibition Immunoassay method (Kit reagent from Roche Diagnostic, Thailand).The results from this study, the mean value of HbA_1c obtained from EDTA blood and NaF blood samples were 8.293 ± 2.076 and 8.265 ± 2.086 respectively. There was no sig
nificant difference between the HbA_1c value obtained from EDTA blood and NaF blood (p > 0.05), mean difference 0.028 and regression equation y = 0.999x-0.019, r = 0.994. In conclusion, the value of HbA_1c measured from NaF blood samples was almost equal value with that of the EDTA blood sample. Therefore, at Songklanagarind Hospital, the NaF blood sample can be used to determine HbA_1c as well as EDTA blood.