Abstract
Thirty-seven patients with SCD were studied: 24 were diagnosed as homozygous Hb S on the basis of their haematological findings, and alpha:non-alpha globin chain ratios were found to be balanced in all. Thirteen patients were thought to have alpha or beta thalassaemia interaction with Hb S on the basis of low MCV and MCH, family history and/or presence of Hb A on electrophoresis. Six of them had abnormal alpha:non-alpha ratio (one had a ratio of 0.72 suggestive of alpha thalassaemia, and five had ratios between 1.4 and 1.9, compatible with beta thalassaemia interaction). The remaining seven patients with microcytosis had balanced globin chain synthesis and five were found to be iron deficient. Five additional patients (3 with Hb SS and 2 with Hb S/beta thalassaemia) had lower than normal serum ferritin concentration. The analysis of case histories disclosed that peptic ulceration, recurrent epistaxis and multiple pregnancies could account for iron loss in seven patients. These findings indicate that iron deficiency may be common in SCD and should be excluded as a cause of microcytosis. Microcytosis, in the absence of conclusive family studies and/or presence of Hb A on electrophoresis, is an unreliable indicator of alpha or beta thalassaemia interaction with Hb S.