A 48-year-old woman moved to a new area and is being seen for a routine physical examination as a new patient in a general medicine clinic. Her present medical history is significant for a 30-lb weight excess and an 8-year history of noninsulin-dependent diabetes mellitus, which she reports has been fairly well controlled with oral agents and a strict diet regimen. However, she is now anxious about her condition and admits to recently developing poor and irregular eating habits, and occasionally missing a medication dosage due to the high stress level surrounding her recent move. The most accurate estimation of this patient's recent glucose control would be which of the following?

Question

Quizplus · Accepted Answer

Glycated hemoglobin (HbA1c) reflects average blood glucose levels over the past 2-3 months, providing a reliable measure of recent glucose control. When present in high concentration, glucose can react nonenzymatically with protein amino groups to form an unstable intermediate, or Schiff base, which subsequently undergoes an internal rearrangement to form a stable glycated protein. The glycation of the amino acids valine and lysine on the b chain of hemoglobin A results in the formation of hemoglobin A_1c (HbA1c), or glycated hemoglobin. Because red blood cells circulate for an average of 90 to 120 days, assaying HbA_1c provides an index of a diabetic patient's glucose control over the preceding 3 to 4 months. Although normal values vary between laboratories, on average nondiabetic subjects have HbA_1c levels roughly between 4% and 6%.

A 48-Year-Old Woman Moved to a New Area and Is