Comparison of capillary electrophoregram among heterozygous Hb Hope, Hb Hope/α-thalassemia-1 SEA type deletion and Hb Hope/β(0)-thalassemia.

BACKGROUND

Hemoglobin (Hb) A(2) is artifactually elevated in cases of heterozygous Hb Hope when measured by capillary electrophoresis (CE). However, there is no report of HbA(2) levels and capillary electrophoregrams for associations of heterozygote of Hb Hope with α-thalassemia nor β-thalassemia.

METHODS

Levels of HbA(0), HbA(2) and Hb Hope in 16 heterozygous Hb Hope, 3 Hb Hope/α-thalassemia-1 SEA type deletion and 2 Hb Hope/β(0)-thalassemia were measured by CE. Electrophoregram and the levels of those were compared within these three groups.

RESULTS

Artifactually elevated HbA(2) levels (≥4%) were found in both groups of heterozygous Hb Hope and Hb Hope/α-thalassemia-1 SEA type deletion. Manual corrections were performed by adjusting baselines, and results showed that means of HbA(2) in both groups decreased from 4.47% and 4.03% to 1.93% and 1.77%, respectively. The highest levels of HbA(2) and Hb Hope were observed in samples with Hb Hope/β(0)-thalassemia. Moreover, HbA(0) was not observed in these cases.

CONCLUSIONS

The elevation of HbA(2) in patients with heterozygous Hb Hope and with Hb Hope/α-thalassemia-1 SEA type deletion measured by CE leads to incorrect β-thalassemia trait diagnosis. However, using CE electrophoregram together with levels of HbA(0), HbA(2) and Hb Hope would be a more accurate and precise method for diagnosis of Hb Hope/β(0)-thalassemia.