HP and gestational diabetes: A ROC analysis was performed to determine the predictive power of the plasma zonulin level for the GDM and showed that the plasma zonulin level of 20 ng/mL or above had a sensitivity of 98.8%, a specificity of 100%, a positive predictive value (PPV) of 98.8%, and a negative predictive value (NPV) of 100% (Figure 2).