Awanui is harmonising HbA1c testing across all laboratories by transitioning from the Bio-Rad D-100 to the Roche C513 platform. Awanui Auckland has successfully used the Roche platform for several years, and this change aligns with our commitment to improving efficiency and maintaining high-quality patient care.
The new method came into effect on 28 July 2025 (Please note, this does NOT affect testing provided by Hastings Hospital Laboratory).
Reference Interval Update for Roche Methodology
The HbA1c reference interval changes to <42 mmol/mol to reflect the characteristics of the Roche methodology.
Analytical method changes can sometimes result in slight shifts in baseline values due to differences in assay design and detection principles. In such cases, revising the reference interval is a routine laboratory practice to ensure consistency in clinical interpretation. During method comparison, the Roche assay remained within the allowable analytical specifications across the measurable range:
- ±4% for values up to 45 mmol/mol, and
- ±8% for values >45 mmol/mol
While this level of analytical variation is technically not expected to impact clinical management significantly, we acknowledge feedback from some primary care providers regarding a noted slight upward shift in some patient results. We recommend repeating HbA1c testing in approximately one month to establish a new baseline for your patient if results appear inconsistent with clinical expectation.
Although no concerns were raised by diabetes specialists, we recognise that patients with borderline or high-normal HbA1c levels in primary care settings may be most affected by the methodological shift. Borderline HBA1C values still merit clinical attention, typically beginning with lifestyle and dietary intervention before initiating pharmacological treatment. We are confident in the accuracy of the Roche HbA1c assay.
For further information or to discuss specific cases, please contact your local Awanui Laboratory team.
Considerations for Hb Variants and Analytical Limitations
The Roche C513 method, like other HbA1c assays, may be affected by haemoglobin variants (e.g., HbS, HbC, HbE) and certain rare haemoglobinopathies, potentially leading to inaccurate HbA1c results. While the C513 has improved variant detection compared to earlier methods, some interferences remain. In cases where results are inconsistent with the clinical picture, the following approach is recommended:
- Alternative Biomarkers: If an Hb variant is suspected or the HbA1c result does not correlate with clinical findings, consider using fructosamine or glucose-based criteria (fasting glucose, oral glucose tolerance test) to assess glycaemic control.
- Clinical Correlation: Regularly review patient history, ethnicity, and previous HbA1c trends, particularly for patients with known haemoglobinopathies.
- Laboratory Alerts: When an interfering Hb variant is suspected, the laboratory will issue a comment advising alternative assessments.
We appreciate your support in implementing this change. If you have any questions or require further clarification, please do not hesitate to reach out.
Dr Melissa Yssel
Clinical Lead – Chemical Pathology, Awanui Labs