Incidental detection of haemoglobin (Hb) variants during high performance liquid chromatography (HPLC) analysis of HbA1c: is it time for a standardised approach to reporting?

BACK GROUND

Haemoglobin (Hb) variants are genetic variations in the globin genes that code for an abnormal globin protein structure. The prevalence of Hb variants has increased in Ireland due to the number of emigrants from Africa and Southeast Asia. The rate of incidentally detected Hb variants, in laboratories employing HPLC to measure HbA1c, has increased in parallel. The presence of a Hb variant can compromise HbA1c measurement and interpretation. In such cases, HbA1c cannot be used to diagnose diabetes or to assess concordance with glycaemic targets.

AIM

To establish the number of incidentally identified Hb variants during 10 months of routine HbA1c analysis, and the percentage of HbA1c reports alerting the requesting clinician to the presence of a Hb variant.

METHODS

The laboratory database was interrogated to extract all records of HbA1c requests and incidentally identified Hb variants from March to December 2012.

RESULTS

A total of 32,636 HbA1c analyses were performed during the evaluation period. Seventy-three Hb variants were identified in a total of 46 patients. In 32.6% (15 of 46) the haemoglobinopathy status was known prior to testing and 97% of HbA1c reports communicated the presence of the Hb variant to the requesting clinician.

CONCLUSION

Hb variants may invalidate the results of HbA1c analysis and could result in a missed diagnosis or a misdiagnosis of diabetes or mismanagement of a patient with diabetes mellitus. It is, therefore, imperative that a comment alerting the requesting clinician to the presence of the Hb variant is appended to the HbA1c result.