Table 1

Advantages of A1C testing compared with FPG or 2HPG for the diagnosis of diabetes

  • Standardized and aligned to the DCCT/UKPDS; measurement of glucose is less well standardized

  • Better index of overall glycemic exposure and risk for long-term complications

  • Substantially less biologic variability

  • Substantially less preanalytic instability

  • No need for fasting or timed samples

  • Relatively unaffected by acute (e.g., stress or illness related) perturbations in glucose levels

  • Currently used to guide management and adjust therapy