Evaluation of Random Plasma Glucose with Lowered Cutoff Limits for Screening of Diabetes and Prediabetes

Abstract

Objective: To evaluate whether random plasma glucose (RPG) can be used as predictive marker and to determine lower cut off limits for screening of undiagnosed diabetes and prediabetes.

Study Design: Cross-sectional study

Place and Duration of Study: Department of Chemical Pathology, Rehman Medical Institute, Peshawar, Pakistan from 1^st July, 2020 to 31^st December, 2020.

Methodology: Two hundred and sixty four subjects having RPG less than 200mg/dl were selected and then OGTT was done according to ADA guidelines. Enzymatic hexokinase method (reference method) using Cobas c501 ® analyzer was used for measurement of plasma glucose.

Results: Mean age of patients was 39.92±12.49 years. There was significant difference (p=<0.001) between mean values of RPG in non-diabetics and diabetics at 95% confidence interval. Post-hoc analysis showed statistically significant difference between these groups. On applying ROC curve for prediabetics, it showed AUC of 0.777 while for diabetes it showed 0.922 at 95% CI. Diagnostic efficacy of RPG for prediabetics and diabetics at different cut off values was evaluated and it was found that sensitivity and specificity for prediabetics was good and for diabetics was excellent at cut off of 136mg/dl.

Conclusion: Random plasma glucose can be used as a reliable screening tool for initial diagnosis of diabetes and prediabetes. A random cut off value of 136 mg/dl can be used as a reliable limit for screening purposes and can be confirmed by using OGTT.

Keywords: Oral glucose tolerance test, Random plasma glucose, ROC curve, Diabetes, Prediabetes