A 19-year-old man with homozygous sickle cell disease is monitored for glycemic control. His fasting glucose values over three months average 140 mg/dL, yet his HbA1c is consistently 5.4%. Which investigation best reflects his true glycemic control?
- A Repeat HbA1c using a boronate affinity assay
- B Serum fructosamine level ✓
- C Fasting C-peptide
- D Urinary albumin-to-creatinine ratio
Correct answer: B. Serum fructosamine level
Explanation
HbA1c depends on red cell lifespan. In hemolytic states such as sickle cell disease, shortened erythrocyte survival falsely lowers HbA1c regardless of assay method, so switching assays does not help. Fructosamine reflects glycation of serum proteins over roughly two to three weeks and is independent of red cell turnover, making it the correct monitoring tool here.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.