The earliest indicator of response after starting iron in a 6–year–old girl with iron deficiency is –

The reticulocyte count is the first to rise. This is followed by elevation of haemoglobin levels. body iron stores are restored after correction of haemoglobin levels. `Rise in Reticulocyte count occurs by the second or third day. This is followed by elevation of haemoglobin levels. Body iron stores are repleted after correction of haemoglobin levels. - Ghai Thus Rise in Reticulocyte count → Rise in Haemoglobin Restoration of iron stores ferritin  Time Span Within 1 day (24 hours) Within 2 days (48 hours) Within 2-3 days Up to 2 months Still later Responsible with the start of iron therapy The child becomes less irritable Appetite improves Initial bone marrow response Reticulocyte count increases Restoration of haemoglobin levels Restoration of iron stores (Ferritin levels)