Comparing Glucometer-Based and Laboratory-Based OGTT for Diabetes Diagnosis: A Narrative Review

Background: The oral glucose tolerance test (OGTT) is the gold standard for diagnosing diabetes; however, its use is often limited by the need for laboratory infrastructure, trained personnel, and extended turnaround times. In contrast, glucometer-based OGTT offers a convenient and affordable alternative, especially in resource-limited settings. Objective: This narrative review aims to assess the diagnostic accuracy of glucometer-based OGTT compared to standard laboratory-based OGTT, while also evaluating its feasibility and potential application in diabetes screening programs. Evidence Summary: Studies consistently demonstrate a strong correlation between capillary glucose levels measured by glucometers and venous plasma glucose concentrations obtained through standard laboratory methods. Many studies reported high sensitivity and specificity, often exceeding 90%, particularly when using well-calibrated, newer-generation devices. These findings support the diagnostic utility of glucometer-based OGTT in various populations, although performance may vary by device model and clinical context. Standardization of testing protocols remains essential for consistent results. Conclusions: Glucometer-based OGTT shows promise as a reliable, rapid and cost-effective diagnostic approach, particularly in low-resource and community-based settings. While it is not a complete substitute for laboratory-based OGTT, it offers substantial advantages in accessibility, affordability, and scalability. Continued research with newer-generation glucometers and standardized testing protocols is essential to support broader clinical implementation and public health integration.