Iron deficiency and anaemia in children with a high prevalence of haemoglobinopathies: implications for screening

Haemoglobin (Hb) concentration is used as a sole test for iron deficiency anaemia (IDA) in most developing countries since most anaemia is believed to be due to iron deficiency and confirmatory testing is generally unavailable. Yet the validity of this approach in regions where haemoglobinopathies are endemic has not been documented.

Haemoglobin and serum ferritin (SF) were measured in 559 Northern Thai children aged 6 months to 13 years of age. The sensitivity of SF to identify iron deficiency was also assessed in a subsample of children with low or low-normal Hb and normal SF by testing the Hb response to a trial of oral iron.

While anaemia was common (27%), IDA constituted 19% and none of all anaemia in preschool and school age children, respectively (P < 0.002). Iron depletion was similarly more prevalent in younger children (P < 0.002). Children with IDA were younger (P < 0.001) and the anaemia more severe (P < 0.0001) compared to those with non-IDA. Of anaemic children with normal SF values who received a therapeutic trial of iron, only 6% responded with an increase in Hb of > or = 1 g/dl.

For populations such as ours most anaemia is not due to iron deficiency and a single Hb determination is therefore not acceptable for a presumptive diagnosis of IDA.