Abstract

Anaemia is defined by the haemoglobin concentration in peripheral blood being below the normal 14 gm/dL (SD ± 2) for women, 16 gm/dL (SD ± 2) for men and 12 gm/dL (SD ± 2) for children. The number of red blood cells is also usually reduced, below the normal 4.8 × 10⁶/mm³ (SD ± 0.6) for women and 5.4 × 10⁶/mm³ (SD ± 0.9) for men. The haematocrit is the proportion of red blood cells in the blood – normally more than 40% for men and 37% for women. The other major red blood cell indices that may be helpful in the differential diagnosis of anaemia are:

• the mean corpuscular volume (MCV), which is the average red blood cell size and is normally 87 u³ (SD ± 5);

• the mean corpuscular haemoglobin (MCH), which is the amount of haemoglobin per cell, normally 29 pg of haemoglobin/cell (SD ± 2);