This is the first report of glycated haemoglobin (Hb) eluting in zone 10 on capillary zone electrophoresis (CZE). In an index case, the aberrant peak was picked up during routine haemoglobinopathy testing using CZE. Mass spectrometry (MS) revealed this aberrant peak to be glycated Hb. Prompted by this initial case, a study was undertaken and the results showed that there was a strong positive linear relationship (R2 = 0.774; ρ = 0.88) between the level of glycated Hb peak eluting in zone 10 and the HbA1c value. Furthermore, all samples with an HbA1c of 54 mmol/mol or greater had an HbA1c peak eluting in zone 10.

Only four cases of Hb I-Toulouse have been reported to date. Current literature associates Hb I-Toulouse in the heterozygote with a mild chronic hemolytic anemia. The variant is mildly unstable with a tendency to form metHb. The quantity of the variant in heterozygotes has been reported as varying between 33 to 40%. This report confirms the finding from a single case, that a reduced percentage of Hb IToulouse along with microcytosis can be attributed to the co-inheritance of an abnormal α globin genotype. This current case was found in a woman of Pacific People ethnicity residing in New Zealand. There is a high prevalence of α thalassemia in this ethnic group and New Zealand has the highest Pacific population in the world. Therefore, if a reduced percentage of Hb I-Toulouse is found with microcytosis and normal iron studies, co-inheritance with α thalassemia should be considered.

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