Diagnostic Methods for Diabetes and Glucose Metabolism

Diagnosis of diabetes and assessment of glucose metabolism rely on a combination of biochemical assays and dynamic tests that capture both fasting and postprandial glycaemia. Fasting plasma glucose (FPG) remains a fundamental measure, defined by standardized thresholds to distinguish normal glycaemia, prediabetes and diabetes. Glycated haemoglobin (HbA1c) provides an integrated index of average plasma glucose over the preceding two to three months and has gained global acceptance as a diagnostic criterion. The oral glucose tolerance test (OGTT) evaluates the body’s capacity to clear an oral glucose load, offering sensitivity in detecting early dysglycaemia. Emerging modalities such as continuous glucose monitoring (CGM) and non-invasive sensors are expanding the toolkit for real-time glycaemic profiling, while alternative biomarkers—fructosamine and glycated albumin—offer shorter-term glycaemic insights. Advances in machine-learning algorithms applied to routine laboratory data aim to refine risk prediction and uncover diagnostic patterns in large populations. Together, these methods provide a multifaceted approach that balances accuracy, feasibility and resource allocation to improve detection, classification and management of dysglycaemia worldwide.

Research from Nature Portfolio

Recent large-scale analyses have illuminated regional differences in the performance of FPG and HbA1c for diabetes detection. Global population survey data demonstrate that reliance on FPG alone may underestimate undiagnosed diabetes in many low- and middle-income regions, where isolated elevations in HbA1c are more prevalent. Novel prediction models now enable estimation of the probability that an individual with a specified FPG level will exhibit elevated HbA1c, facilitating targeted deployment of glycation testing and optimising scarce laboratory resources. Foundational work in normative cohorts has also refined age- and sex-specific reference ranges for HbA1c in youth and young adults. Detailed percentile distributions reveal significant differences across age strata and between males and females, underscoring the need for tailored diagnostic thresholds that account for demographic variation.

Diagnostic Methods for Diabetes and Glucose Metabolism publication trend

The graph below shows the total number of articles in diagnostic methods for diabetes and glucose metabolism across all publications each year (not limited to Nature Index journals).

Technical terms

Fasting Plasma Glucose (FPG): The concentration of glucose in venous blood after an overnight fast, used to detect baseline dysglycaemia.

Glycated Haemoglobin (HbA1c): A biomarker reflecting the proportion of haemoglobin molecules that have glucose irreversibly bound, indicating average glycaemic exposure over the previous two to three months.

Oral Glucose Tolerance Test (OGTT): A dynamic assessment in which plasma glucose is measured before and two hours after ingestion of a standardized glucose solution to evaluate postprandial glucose handling.

References

1. Global variation in diabetes diagnosis and prevalence based on fasting glucose and hemoglobin A1c. Nature Medicine (2023).
2. Effect of ethnicity on HbA1c levels in individuals without diabetes: Systematic review and meta-analysis. PLOS ONE (2017).
3. Discordance in the diagnosis of diabetes: Comparison between HbA1c and fasting plasma glucose. PLOS ONE (2017).
4. Limited Agreement between Classifications of Diabetes and Prediabetes Resulting from the OGTT, Hemoglobin A1c, and Fasting Glucose Tests in 7412 U.S. Adults. Journal of Clinical Medicine (2020).
5. Distribution of glycated haemoglobin and its determinants in Korean youth and young adults: a nationwide population-based study. Scientific Reports (2018).