<span name="style_bold">Objective: </span>To determine the most sensitive and positive predictive cut-off value for the oral glucose challenge screening test for the diagnosis of gestational Diabetes Mellitus in women with pregnacies between the 24-28 weeks. <span name="style_bold">Methods: </span>Observational study. From the files of the hospital’s laboratory service, every pregnant woman who had an oral glucose tolerance (100g of glucose) test; this test was had been indicated because values of more or equal to 130 mg/dl during of oral glucose challenge screening test (50g of glucose). The glucose levels were quantified by the SYNCHRON CX system. The National Diabetes Data Group criteria were used. Logistic regression model was utilized, and ROC (Receiver Operating Characteristic) curve analysis was done to determine the sensitivity and specificity. The STATA statistical program, version 7, 2000 was used. <span name="style_bold">Results: </span>123 cases were included in the analysis. The cut-off value of the oral glucose challenge screening test for our population was 148 mg/dl. A value of the oral glucose challenge screening test of 177 mg/dl has a sensitivity of 37.5% and a specificity of 96.2%. A value of 133 mg/dl has a sensitivity of 87.5% and a specificity of 12.3%. <span name="style_bold">Conclusion: </span>An oral glucose challenge screening test of 140 mg/dl can be kept as the cut-off value, if the goal of the screening test is to recognize patients with a positive oral glucose tolerance test. Values greater than 177 mg/dl after the oral glucose challenge screening test, determine the need of the oral glucose tolerance test to diagnose gestational diabetes for its high specificity.An oral glucose challenge screening test of 140 mg/dl can be kept as the cut-off value, if the goal of the screening test is to recognize patients with a positive oral glucose tolerance test. Values greater than 177 mg/dl after the oral glucose challenge screening test, determine the need of the oral glucose tolerance test to diagnose gestational diabetes for its high specificity.

Gestational diabetes; challenge screening test; cut-off value