Glycohemoglobin as a screening test for gestational diabetes

This study evaluated the feasibility of utilizing hemoglobin A1c as a screening test for gestational diabetes. We compared this test in 82 women in the third trimester of pregnancy to a glucose tolerance test in which a glucose load of 100 gm was used. At its best index of correlation, hemoglobin A1c at 7% is concordant with the glucose tolerance test in 69% of the cases, false positive in 41%, and false negative in 26%. Though the two procedures correlate very well, the high incidence of false negative and positive for hemoglobin A1c make this test inadequate as a screening procedure for gestational diabetes.