HbA1c method change at Princess Royal University Hospital

From Wednesday 6th May 2020, HbA1c will be measured by a new method of analysis at Princess Royal University Hospital (PRUH) due to an upgrade of analytical equipment. The previous Menarini boronate affinity HPLC method will be replaced with the Roche Gen 3 Tina-Quant (TQ3) HbA1c immunoassay. Our verification studies have shown that the new method, whilst a different analytical principle, compares well with the existing HbA1c method and no clinically significant differences in results are expected. There will be no change in the interpretation guide reported with all HbA1c results.

Haemoglobin variants

The Roche TQ3 immunoassay method specifically detects the first four amino acids of the N-terminal of the Hb β-globin chain (i.e. including the N-terminal valine) and thus meets IFCC criteria for standardisation of HbA1c measurement. Various papers in the literature have demonstrated that the TQ3 method is not affected by interferences from the common haemoglobin variants (HbAS, HbAE, HbAC, HbAD) or acetylated or carbamylated haemoglobins; however the assay is affected by HbF concentrations >7 %. We will be conducting studies to verify these claims and gain a greater understanding of how haemoglobin variants affect HbA1c measurement. Until then, if a haemoglobin variant is suspected or known or if the patient has >7% HbF then an alternative method of HbA1c analysis using Menarini boronate affinity HPLC should be performed.

Please contact the lab on 01689 864256 to discuss. Please note that HbA1c samples will only be stored for 3 days after analysis, any requests for HbA1c measurement by HPLC made after 3 days will require a new sample.