Early identification of dysglycemia is essential to delay the progression to diabetes. CGM provides detailed glucose profiles that may outperform conventional diagnostic methods for prediabetes detection. This study, published in the Journal of Diabetes Science and Technology, established reference intervals for CGM metrics in normoglycemic (NG) Asian adults and explored their ability to distinguish prediabetes.

Healthy participants were classified using American Diabetes Association criteria via a 75 g oral glucose tolerance test and hemoglobin A1c (HbA1c). A total of 151 adults without diabetes, including 27 with prediabetes, underwent blinded CGM monitoring. Reference intervals for NG included mean glucose (78 to 106 mg/dL), time in range (TIR) 70 to 180 mg/dL (69 to 100%) and 54 to 140 mg/dL (86.4 to 100%), TAR >140 mg/dL (0 to 9.7%), and glucose standard deviation (10.9 to 25.6 mg/dL).

Among all CGM parameters, TAR >140 mg/dL achieved the highest area under the receiver operating characteristic curve (AUROC 0.72), with an optimal diagnostic threshold of 5.6%. These findings indicate that Asians with normoglycemia spend most of their time within the 54 to 140 mg/dL range, and TAR >140 mg/dL may serve as a simple, practical marker for early detection of prediabetes.