RETROGRADE VERSUS ANTEGRADE CANNULATION IN THE INTRAVENOUS GLUCOSE-TOLERANCE TEST

To investigate whether drawing blood from a retrogradely cannulated ha nd vein rather than an antegradely cannulated arm vein improves reprod ucibility in the intravenous tolerance test (IVGTT) we compared these two methods directly by drawing blood from the two sites on the same a rm simultaneously. We found no difference in intrasubject coefficients of variation for the measurement of insulin response to glucose (21.5 % vs. 22.5%) or insulin sensitivity (22.8 vs. 24.7%) for these two met hods. However, the values for insulin response to glucose were signifi cantly increased when blood was drawn from the hand site (410.1 vs. 32 8.7 pM, P < 0.05). In addition, the failure rate for studies using the retrogradely cannulated hand vein was significantly increased (5% of arm veins vs. 20% of hand veins cannulated, P < 0.05) particularly in female subjects. In conclusion, drawing blood samples from a retrograd ely cannulated hand vein appears to have no effect on the reproducibil ity of the intravenous glucose tolerance test. The acute insulin respo nse to glucose obtained from samples drawn in this manner is, however, significantly increased and this should be borne in mind when compari ng results from centers using these different methods.