PREDICTIVE VALUE OF HEMOCUE CAPILLARY WHOLE-BLOOD GLUCOSE MEASUREMENTS IN PREGNANCY

OBJECTIVE: We determined the ability of capillary whole blood glucose concentrations to predict venous plasma and whole blood glucose levels . METHODS: During a standard oval glucose tolerance test in 29 pregnan t women, paired capillary and venous blood samples were collected for analysis of glucose concentrations by the HemoCue photometer and by ce ntral laboratory methods. RESULTS: Glucose concentrations determined s erially in a single blood sample by the HemoCue method were highly rep roducible, with a coefficient of variation of 2.3%. However, glucose l evels in blood from two different fingersticks from the same patient v aried on average by 3 mg/dL, with a maximum difference of 24 mg/dL. Al though capillary whole blood glucose results obtained by the HemoCue m ethod correlated well with venous plasma or whole blood glucose measur ements (r = 0.98 and r = 0.97, respectively) over the range investigat ed (60-250 mg/dL), individual capillary whole blood glucose measuremen ts were only a fair predictor of venous values, with 95% of measured v enous levels within +/-26 mg/dL and +/-20 mg/dL for concentrations pre dicted for plasma and whole blood, respectively. CONCLUSION: Sampling factors rather than measurement accuracy limit the ability of capillar y whole blood glucose measurements to predict venous concentrations.