Comparison of capillary whole blood versus venous plasma glucose estimations in screening for diabetes mellitus in epidemiological studies in developing countries.

BACKGROUND: This study compared capillary blood glucose (CBG) measurements with venous plasma glucose (VPG) measurements in screening for diabetes and prediabetes in epidemiological studies.
METHODS: Four hundred seven subjects ≥ 20 years old (54.1% male) without previously known diabetes underwent oral glucose tolerance tests at a tertiary diabetes center in Chennai, India. Simultaneous measurements of CBG (OneTouch(®) Ultra(®) meter, LifeScan, a Johnson & Johnson Company, Milpitas, CA) and VPG (AU2700, Beckman, Fullerton, CA) were performed, both in the fasting state and 2 h after a 75-g glucose load (2-h post-glucose [PG]). Diabetes, impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) were defined using American Diabetes Association (ADA) and World Health Organization (WHO) criteria.
RESULTS: The mean fasting CBG and VPG values were 122 ± 39 mg/dL and 115 ± 40 mg/dL, respectively, and the 2-h PG values were 203 ± 84 mg/dL and 176 ± 85 mg/dL, respectively. The Pearson's correlation coefficient for CBG with VPG was 0.681 (P < 0.001) in the fasting state and 0.897 (P < 0.001) for the 2-h PG load, indicating good correlation between the two methods. Based on the ADA fasting criteria, 31.9% versus 21.1% (capillary vs. venous) had diabetes, whereas based on the WHO criteria, 43.2% versus 38.6% (capillary vs. venous) had diabetes. The accuracy of identifying diabetes was 83.3% by the ADA and 90.9% by WHO criteria, for IGT it was 85.3%, and for IFG it was 66.3% by the ADA and 72.2% by the WHO criteria.
CONCLUSION: CBG is a feasible alternative for screening of diabetes and IGT in epidemiological studies in developing countries where obtaining venous samples may be difficult.