A total of 4 level Ⅰ laboratories certificated by the National Glycohemoglobin Standardization Program (NGSP) and a laboratory by the International Federation of Clinical Chemistry and Laboratory Medicine(IFCC)were comprised the proposed reference laboratory network. SHGHP website was established, and whole blood calibrators and comparative specimens were sent to all participating clinical laboratories. The harmonization of results before and after calibration was compared. The mean value, standard deviation and coefficient of variation(CV) of HbA_1c detected by the laboratories before and after calibration were calculated and analyzed for difference statistically.

The CV of low-level and high-level HbA_1c by the 5 reference laboratories were 2.27% and 1.58%, respectively. The CV of HbA_1c detected by the third-grade hospitals after calibration decreased significantly than that before calibration (P<0.001). The CV after calibration ranged from 0.94% to 4.22%. The percentages of passed laboratories in SHGHP from 2012 to 2013 were above 90% in which the third-grade hospitals all passed the evaluation.

SHGHP calibrates the different methods by fresh whole blood with no significant matrix effects and improves the harmonization of HbA_1c significantly among the participating laboratories.