Diagnostic Approaches in Type 2 Diabetes Evaluation

Type 2 diabetes is diagnosed using a combination of clinical risk assessment, biomarkers of glycaemia and functional tests. Central to evaluation are measures of blood glucose concentration, including fasting plasma glucose (FPG) and the oral glucose tolerance test (OGTT), which quantify acute glycaemic status, and the measurement of glycated haemoglobin (HbA1c), which reflects chronic exposure to elevated glucose. Advances in assay standardisation and threshold optimisation have clarified variable sensitivity and specificity across populations. Novel diagnostic algorithms now integrate risk scores, non-invasive measures of insulin resistance and point-of-care devices. Emerging technologies, such as continuous glucose monitoring and machine-learning–based risk stratification, are improving early detection and personalised evaluation. A comprehensive diagnostic strategy balances analytical accuracy with practical accessibility, ensuring global applicability across diverse healthcare settings and facilitating timely intervention to reduce complications.

Research from Nature Portfolio

Recent studies have explored the impact of biological and analytical variation on test performance. Numerical simulations based on large population cohorts indicate that within-individual biological variation and analytical imprecision can markedly influence the classification of diabetes when using FPG, OGTT and HbA1c. These findings highlight the value of repeat testing and averaging results to reduce misclassification and support the adoption of assays with low analytical coefficient of variation.

Investigations in multi-ethnic Asian cohorts have compared HbA1c and FPG as first-line screening tools. Analyses reveal that although FPG generally produces a marginally higher area under the receiver-operating-characteristic curve, HbA1c offers operational advantages for non-fasting sampling. Race-specific differences in test performance underscore the need for tailored cut-offs to optimise sensitivity and specificity in diverse populations.

Diagnostic Approaches in Type 2 Diabetes Evaluation publication trend

The graph below shows the total number of articles in diagnostic approaches in type 2 diabetes evaluation across all publications each year (not limited to Nature Index journals).

Technical terms

Glycated haemoglobin (HbA1c): A measure of average blood glucose over the preceding two to three months, expressed as a percentage of haemoglobin bound to glucose.

Fasting plasma glucose (FPG): The concentration of glucose in venous blood after an overnight fast, used to assess baseline glycaemia.

Oral glucose tolerance test (OGTT): A functional challenge involving a measured glucose load followed by serial blood glucose measurements to evaluate glucose handling.

Sensitivity: The proportion of true positives correctly identified by a diagnostic test, reflecting its ability to detect disease.

Specificity: The proportion of true negatives correctly identified, indicating a test’s ability to exclude disease.

Area under the curve (AUC): A summary measure of diagnostic performance derived from the receiver-operating-characteristic curve, with higher values indicating greater accuracy.

References

1. Impact of analytical and biological variations on classification of diabetes using fasting plasma glucose, oral glucose tolerance test and HbA1c. Scientific Reports (2017).
2. Screening for diabetes with HbA1c: Test performance of HbA1c compared to fasting plasma glucose among Chinese, Malay and Indian community residents in Singapore. Scientific Reports (2018).
3. Optimal glycated hemoglobin A1c value for prediabetes and diabetes in patients with pancreatic diseases. Frontiers in Endocrinology (2023).
4. Discrepancy in diagnoses of diabetes and prediabetes using fasting plasma glucose and glycosylated hemoglobin and the underdiagnosis by ICD-10 coding: data from a tertiary hospital in Thailand. Frontiers in Public Health (2023).