Awanui Labs have recently harmonised HbA1c testing across our South Island laboratories by transitioning from the BioRad D-100 to the Roche C513 platform. This change aligns with Awanui’s commitment to improving efficiency and maintaining high-quality patient care.
As part of this harmonisation, the HBA1C reference interval was just standardised to <41 mmol/mol (compared to the current stated reference interval of 20-40 mmol/mol in some regions).
There is no change in current HbA1c diagnostic, monitoring and treatment thresholds.
These parameters may be adjusted in due course, awaiting national change approval from Health NZ and other NZ Diabetes working groups. These changes will ensure consistency and alignment with best-practice guidelines across all public and private laboratories nationwide.
For now, there is no change in clinical HbA1c interpretation or diabetes management practices.
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.
If you have any questions or require further clarification, please do not hesitate to contact Awanui Chemical Pathologists:
Dr Owen Wiese – Owen.Wiese@awanuigroup.co.nz
Dr Melissa Yssel – Melissa.Yssel@awanuigroup.co.nz