Challenges in HbA1c analysis and reporting: An interesting case illustrating the many pitfalls

This case study illustrates the challenges in the analysis and interpretation of HbA1c testing. The patient is homozygous HbS with a high HbF concentration. Immunoassay methods give an HbA1c result that probably reflects glycated hemoglobin species (although falsely low) while HPLC methods gave a zero HbA1c result. The equating of glycated hemoglobin variant species to published target HbA1c values may not be relevant in patients with homozygous variants due to potential difference in glycation rates and analytical (in this case HbF interference with the immunoassay method) and physiological challenges (markedly decreased the red cell survival).