Can Glycosylated Hemoglobin and Fasting Blood Sugar Replace Glucose Challenge Test in Screening for Gestational Diabetes?

Objectives: The present study aimed to compare the diagnostic values of glycosylated hemoglobin (HbA1c) and fasting blood sugar (FBS) using the glucose challenge test (GCT) in screening for gestational diabetes. Materials and Methods: A total of 618 women at 24-28 weeks of pregnancy were selected, and their FBS and HbA1c were measured using the GCT. The obtained results were compared in terms of sensitivity, specificity, as well as positive and negative predictive values using the ROC curve. Results: At the cut-off point of 1.4, sensitivity was 69.74% and specificity was 69.05 for the FBS test; at the cut-off point of 6.6, sensitivity was 90.79% and specificity was 80.95% for the HbA1c test; the area under the ROC curve was 0.925 with a 95% confidence interval (0.979, 0.872). Conclusion: The diagnostic values of the HbA1c test and GCT were favorable in screening for gestational diabetes; the HbA1c test also showed a high diagnostic value in women with positive OGCT and GCT results.