A 30-year-old woman with treated autoimmune haemolytic anaemia and type 1 diabetes needs assessment of recent glycaemic control. Her HbA1c reads 5.1% despite home glucose logs showing frequent readings above 250 mg/dL. Which test best reflects glycaemia over the preceding 2 to 3 weeks?
- A Repeat HbA1c from a different laboratory
- B Fasting plasma glucose on two occasions
- C Serum fructosamine level ✓
- D Urinary glucose excretion over 24 hours
Correct answer: C. Serum fructosamine level
Explanation
Fructosamine reflects non-enzymatic glycation of serum proteins, chiefly albumin, and therefore estimates average glucose over roughly 2 to 3 weeks. It is unaffected by red cell lifespan, so it is the correct choice when haemolysis, recent transfusion, or haemoglobinopathy falsely lowers HbA1c. Repeating HbA1c will reproduce the same artefact because shortened erythrocyte survival underestimates true glycaemia regardless of the assay laboratory.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.