how much iron is in a unit of blood
One gram of haemoglobin contains 3.4 mg of iron. In a normal individual with 15 g of haemoglobin per dl, 100 ml of blood contains approximately 50 mg of iron. Thus removal of only 2 ml of blood results in the loss of 1 mg of iron3. If 450 ml of blood are taken in a donation approximately 225 mg of iron will be lost. If the donor has no iron deficiency, the erythrocytes and the haemoglobin level will generally return to normal within 34 weeks. Hence adequate iron stores are very important in maintenance of the donor health4.
A unit of blood is equivalent to approximately 1 pint or 450 milliliters, according to the Canadian Blood Services website. The average patient requires around 4.6 units of blood.