Comparison of venous blood glucose and capillary blood glucose in the screening of gestational diabetes

Gestational Diabetes mellitus (GDM) is associated with higher rates of fetal and perinatal mortality and morbidity. Screening of GDM using traditional plasma analysis on venous plasma glucose is very expensive and time consuming. The aim of the present study was to compare laboratory venous blood glucose measurement and capillary blood glucose measurement by glucometer in the screening of gestational diabetes.
In this cross sectional study, 256 pregnant women were screened for GDM, by glucometer on capillary blood samples and simultaneously, by laboratory plasma analysis method on venous blood samples, obtained after one-hour 50-g Glucose Challenge test. Statistical analysis was done using SPSS 19 software.
Capillary glucose levels were significantly higher than venous plasma glucose levels. There was a significant correlation between venous and capillary glucose levels. A lower threshold of 157mg/dl (area under the ROC curve=.922) with a 88.5% sensitivity and 87% specificity and an upper threshold of 211 mg/dl (area under the ROC curve=.982) with a 91.7% sensitivity and 95.7% specificity, was determined to diagnose GDM in 24-28 weeks pregnant women, using Reservoir Operating Curve. Using kappa agreement coefficient, a 64% agreement was shown between to two tests, in 24-28 weeks pregnant women, which is of great significance.
GDM screening by glucometer on capillary blood samples, is a highly sensitive and specific test to diagnose GDM and significantly reduces the number of further tests needed for the diagnosis of GDM and is cost saving as well.