Microcytosis: guidelines for family doctors.

In our studies of microcytosis, the complete blood count (CBC) of 82,830 randomly selected patients was analysed. Of these 34.3% showed microcytosis, and 5.5% were not anaemic. Emphasis was given to study the extent, causes and patterns of non-iron deficient microcytosis. Haematological data was adequate to differentiate iron deficient (ID) from non-iron deficient (NID) patients with microcytosis in 285 subjects. Of these 21.4% were found to be NID. A majority (73.8%) had showed a form of haemoglobinopathy, the commonest being beta-thalassaemia minor (60.7%). Of non-invasive investigations, mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), red cell size distribution width (RDW), anisocytosis in blood smears, serum iron (SI) and haemoglobin electrophoresis, the parameter which separated ID from NID patients most effectively was haemoglobin electrophoresis. It showed an abnormal pattern in 82% of NID subjects and normal pattern in 96.4% ID subjects. In the 18% of the NID subjects with a normal pattern, raised serum iron levels characterized 11% additional subjects with NID.