Classification of iron deficiency among infants (aged 6–12 months) and pre-schoolers (aged 29–56 months), Nalgonda district, Telangana, India. , Normal (Hb>110 g/l, ferritin >12 µg/l and soluble transferrin receptor (sTfR)<2·5mg/l); , iron deficiency with no anaemia (IDNA; Hb>110 g/l, ferritin<12 µg/l or sTfR>2·5 mg/l or both); , iron-deficiency anaemia (IDA; Hb<110 g/l, ferritin<12 µg/l or sTfR>2·5 mg/l or both); , anaemia without iron deficiency (Hb<110 g/l, ferritin >12 µg/l and sTfR<2·5 mg/l)