The quantitation of haemoglobin A2 and haemoglobin F: a report of the techniques review group of the Thalassaemia Society of Victoria.

A techniques review group was established in 1975 to investigate the reproducibility of tests for HbA2 and HbF for the diagnosis of beta thalassaemia. Over a 3-year period, 22 samples were distributed for analysis by up to 14 laboratories. Of 250 estimations of HbA2, 26 (10.4%) were at variance with the majority result. The largest number of variant results were obtained in samples with a HbA2 close to the upper limit of normal. Of 238 HbF determinations, 29 (12%) were equivocal or at variance with the majority result. It is concluded that the techniques of HbA2 and HbF estimation as currently practised by several laboratories are not sufficiently accurate, and that, therefore, a number of cases of beta thalassaemia are not being diagnosed. It is the opinion of those participating in the study that the survey is of value in providing a continuing review of techniques and a forum for discussion.