A roadmap for the standardization of hemoglobin A2

Clin Chim Acta. 2021 Jan:512:185-190. doi: 10.1016/j.cca.2020.11.008. Epub 2020 Nov 10.


Background: Standardization of laboratory tests can be a long process, and this is the case with regards to the methods used to measure hemoglobin A2 (HbA2), an important marker for beta-thalassemia and other thalassemic conditions. The IFCC standardization project started in 2004, and it took at least 15 years before developing a reference measurement procedure, defining and producing calibrators and certified reference materials.

Methods: A series of steps have to be undertaken in order to promote the standardization in the field, a process involving a number of stakeholders (manufacturers, scientific societies, national health bodies, laboratory professionals, clinicians). In this work we describe some possible process indicators, in order to assure that the standardization will have internal and external validity and be effective for a long time. These indicators concern the inter-method studies, elaboration of External Quality Assessment Schemes, and the evaluation of the yearly distributions of HbA2 measurements collected in selected laboratories.

Results: Preliminary results are reported concerning the yearly distributions of HbA2, collected in two different locations, and using different analytical methods. Median yearly values were found very constant over the years, but different between methods. On the other side, results obtained on the same specimens using two different techniques, proved that results by capillary electrophoresis in 2 out of the 3 years of observation, were significantly lower than those by HPLC.

Conclusion: In this document we report what has been done so far, and what has to be done to achieve the standardization of the measurement of HbA2 worldwide.

Keywords: Certified reference materials; HbA(2); Reference intervals; Reference measurement procedure; Standardization; Traceability; β-thalassemia.

MeSH terms

  • Calibration
  • Chromatography, High Pressure Liquid
  • Glycated Hemoglobin / analysis
  • Hemoglobin A2* / analysis
  • Hemoglobin, Sickle
  • Humans
  • Reference Standards


  • Glycated Hemoglobin A
  • Hemoglobin, Sickle
  • hemoglobin AS
  • Hemoglobin A2