<prompt> The earliest sign of iron deficiency anaemia -Increase in iron binding capacityDecrease in serum ferritin levelDeorease in serum iron levelAll the above  <response>: Plasma ferritin is a measure of iron stores in tissues is the single test to confirm iron deficiency .It is a very specific test. In the course of development of anaemia, firstly storage ironferritin depletion occurs during which iron reserves are lost without compromise of the iron supply for erythropoiesis.Plasma iron total iron binding capacityTIBC are measures of iron availability ;hence they are affected by many factors besides iron stores.Plasma iron has a diurnal day -to-day variation becomes very low in acute phase response . 