Serum ferritin in megaloblastic anaemia.

Serum ferritin concentrations have been estimated in 30 patients with untreated megaloblastic anaemia, 27 with Addisonian pernicious anaemia. A significant difference was found between the mean serum ferritin level of the 27 pernicious anaemia patients (330 microgram/1) and of 22 normal control subjects (164 microgram/1) (P less than 0.05 greater than 0.02). There was an inverse correlation between serum ferritin and Hb concentration in men with pernicious anaemia but not in women. Serum ferritin levels were lower in 10 of 13 patients studied after 24 h of vitamin B12 therapy and in all 13 studied at 48 h after therapy. The fall continued during the haematological response to therapy. It seems likely that serum ferritin reflects reticuloendothelial iron and the high levels in untreated megaloblastic anaemia are due to the shift in iron from Hb to reticuloendothelial stores. The wide variation in serum ferritin at any given Hb level presumably reflects variation in iron stores of the individual patient.