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 HbA(1c) testing. The patient is homozygous HbS with a high HbF concentration. Immunoassay methods give an HbA(1c) result that probably reflects glycated hemoglobin species (although falsely low) while HPLC methods gave a zero HbA(1c) result. The equating of glycated hemoglobin variant species to published target HbA(1c) 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).