Evaluation of biological variation of glycated hemoglobin and glycated albumin in healthy Chinese subjects

Background: Glycated hemoglobin (HbA1c) and glycated serum albumin (GSA) are used to evaluate the mean blood glucose levels. To ensure safe clinical application of HbA1c and GSA, reliable biological variation (BV) data are required. The aim of this research was to define the BV of HbA1c and GSA employing stringent rules.

Methods: Blood samples were drawn from 19 healthy subjects (10 females, nine males) once per week for 5 weeks. All samples were analyzed using enzymatic method for GSA and HPLC for HbA1c. The data were assessed for outliers, normality and variance homogeneity, and coefficient of variation (by ANOVA) for BV. Sex-stratified BV including within-subject (CV_I ) and between-subject (CV_G ) was defined for HbA1c and GSA.

Results: The following estimates for BV values for CV_I and CV_G , respectively, were GSA: 1.23% and 4.67%, Alb: 0.75% and 3.18%, and HbA1c: 0.12% and 2.91%. The RCV of GSA was 3.61%, and HbA1c was 1.41%. And the II was 0.26 for GSA, and 0.07 for HbA1c, both of them less than 0.6. According to the 95% CI, the CV_I of HbA1c was statistically different between females and males. And both the CV_G of HbA1c and GSA were statistically different between females and males.

Conclusion: All CV_I and CV_G estimates were lower than those reported in the online BV database. And there is a significant difference between males and females. Analytical performance specifications derived from BV of this research can be applied internationally.