A case of discordant HbA1c: a method-dependent error

Goce Dimeski, Carel J Pretorius, Anthony W Russell, Stephen P Miller, Robert J Bird and Jacobus P J Ungerer
Med J Aust 2009; 191 (6): . || doi: 10.5694/j.1326-5377.2009.tb02821.x
Published online: 21 September 2009

Although glycated haemoglobin (HbA1c) has become the key biochemical marker of long-term glycaemic control, analytical method-dependent differences in results can occur when haemoglobin variants are present or HbA1c is reduced by decreased red cell survival. When the measured HbA1c level is discordant with the patient’s blood glucose measurements and clinical status, fructosamine is an alternative biochemical marker that can provide a more accurate estimate of the glycaemic control and enable clinicians to appropriately manage patients.

A 65-year-old, centrally obese man (body mass index, 32.7 kg/m2) with a 23-year history of type 2 diabetes mellitus was referred to a diabetes clinic in January 2008 for stabilisation of his blood sugar levels. His diabetes was complicated by ischaemic heart disease, peripheral vascular disease, hypertension, dyslipidaemia, and stage 3 chronic kidney disease. His glycated haemoglobin (HbA1c) level on referral was 11.0%, measured using an ion-exchange chromatography (IEC) method on a Bio-Rad Variant II analyser (Bio-Rad Laboratories, Sydney, NSW), and the laboratory fasting glucose measurement was 19.3 mmol/L (Box 1). Both these results were consistent with the patient’s home blood glucose measurements (> 10 mmol/L).

  • Goce Dimeski1
  • Carel J Pretorius1
  • Anthony W Russell2,3
  • Stephen P Miller1
  • Robert J Bird1
  • Jacobus P J Ungerer1

  • 1 Pathology Queensland, Brisbane, QLD.
  • 2 Princess Alexandra Hospital, Brisbane, QLD.
  • 3 Diamantina Institute for Cancer, Immunology and Metabolic Medicine, University of Queensland, Brisbane, QLD.

Competing interests:

None identified.


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