Correlation and Regression Analysis Between HbA1c, Fasting Blood Sugar (FBS), and Random Blood Sugar (RBS) levels in Diabetic and Non-Diabetic patients in ElMarj, Libya

Abstract

Diabetes mellitus is a prevalent metabolic disorder requiring reliable diagnostic tools. Hemoglobin A1c (HbA1c), fasting blood sugar (FBS), and random blood sugar (RBS) are commonly used for diagnosis and monitoring. HbA1c offers insight into long-term glycemic control, while FBS and RBS reflect real-time glucose levels. The main aim of this study to evaluate the relationship between HbA1c, FBS, and RBS among individuals attending a private diagnostic laboratory in Elmarj, Libya, and to assess the consistency and strength of these markers. This prospective study included 292 participants from November 2023 to March 2025. HbA1c was measured using fluorescence immunoassay, and FBS/RBS were measured via enzymatic colorimetric methods. Data were analyzed using IBM SPSS Statistics version 26.0. Correlation coefficients and linear regression were applied to assess relationships between variables of the 292 participants, 263 underwent HbA1c and FBS testing, 214 underwent HbA1c and RBS testing, and 187 had all three tests. According to American Diabetes Association criteria, 231 participants (79.1%) were in the diabetic range (HbA1c ≥6.5%). HbA1c showed a moderate positive correlation with FBS (r = 0.68) and a stronger correlation with RBS (r = 0.74), both statistically significant (P < .001). Regression analysis demonstrated consistent positive linear relationships. Concluding that the HbA1c correlates significantly with both FBS and RBS, supporting its utility as a stable marker for long-term glycemic monitoring. The findings reinforce the value of integrating HbA1c with FBS and RBS to enhance diagnostic accuracy in diabetic screening.