Introduction.  This study aimed to assess the relationship between capillary glucose, venous glucose and prandial status, in both healthy volunteers and also women with pregnancy complicated by diabetes.
Methods. Healthy volunteers had concomitant capillary and venous glucose measurements undertaken, before and one hour after breakfast. Pregnant women with diabetes had capillary and venous glucose measured at a routine antenatal clinic visit and the time and amount of their last significant (>10gm) CHO (carbohydrate) load was noted. Capillary glucose was measured using the Freestyle Lite and Performa meter systems. The antecubital venous sample was spun down immediately after collection and plasma analysed in the laboratory.
Results. 106 healthy volunteers and 60 pregnant women participated. Glucose [capillary-venous] differences(SD) for healthy volunteers pre-post breakfast, followed by pregnancy <3 hours and >3 hours post CHO ingestion, are given below (mmol/L):

In healthy volunteers, the change between pre and post breakfast [capillary-venous] difference was significant (p<0.001). The relationship between timing of last CHO ingestion and [capillary-venous] difference was not significant in pregnancy. Further analyses of the relationship between CHO timing and [capillary – venous] difference did not show any augmentation of the observed differences.
Conclusions. In contrast to the change in pre- and post-prandial [capillary-venous] glucose difference seen in the healthy volunteer sub-study, prandial status did not impact on this difference in the real world setting of the diabetes antenatal clinic. We also noted that the [capillary-venous] differences were small in pregnancy, showing that the glucose meters tested are accurate during pregnancy complicated by diabetes.