A woman with a diagnosis of type 2 diabetes has been ordered by her primary care provider to have a hemoglobin A1C test for the first time. The woman states, “I don’t see why you want to test my blood cells when it’s sugar that’s the problem.” What aspect of physiology will underlie the care provider’s response to the patient?The amount of glucose attached to A1C cells reflects the average blood glucose levels over the life of the cell.Hemoglobin synthesis by the bone marrow is inversely proportionate to blood glucose levels, with low A1C indicating hyperglycemia.The high metabolic needs of red cells and their affinity for free glucose indicate the amount of glucose that has been available over 6 to 12 weeks.Insulin is a glucose receptor agonist on the hemoglobin molecule, and high glucose suggests low insulin levels.