Verification studies in glucometers: Should we use capillary blood or venous blood for comparison?

Glucometers are widely used in the diagnosis of blood glucose levels in patients with diabetes mellitus. EN ISO 15197 suggests that glucometer comparison studies should have 100 capillary blood samples be worked on at least twice. In this study, we planned on comparing the glucose results measured in a routine biochemistry analyzer from two different glucometers, capillary and venous blood samples, and aimed to discuss the effects of blood taking systems on the glucometer validation studies. Capillary and venous blood samples were taken from 101 individuals and their glucose concentrations measured simultaneously using two different glucometers (Accu-chek and GlucoMax). Capillary and venous blood samples were centrifuged after clotting and analyzed in the Roche P modular system. In the fasting condition, the equations for regression analysis that were found y=0,873x+24,32 (r=0,857) in between Accu-chek and venous blood glucose, y=0,9x+16,15 (r=0,920) in between Accu-chek and capillary blood glucose, y=0,811x+20,94 (r=0,776) in between GlucoMax and venous blood glucose, and y=0,851x+12,28 (r=0,863) in between GlucoMax and capillary blood glucose.In the postprandial state, the equations were y=0,713x+48,46 (r=0,258) in between Accu-chek and venous blood glucose, y=0,981x+11,77 (r=0,718) in between Accu-chek and capillary blood glucose, y=0,706x+39,12 (r=0,453) in between GlucoMax and venous blood glucose, and y=0,790+22,35 (r=0,787) in between GlucoMax and capillary blood glucose. In the fasting and postprandial state, the capillary glucose levels showed better correlation with glucometer measurements than venous blood glucose levels. In glucometer verification studies, capillary blood obtained with capillary blood sampling systems and used instead of venous blood should be the preferred sample.