Most sensitive and specific test for diagnosis of iron deficiency is -

<p>Plasma ferritin is a measure of iron stores in tissues & is the best test to confirm iron deficiency & is a very specific test . </p><p>Plasma iron & total iron binding capacity are measures of iron availability ;hence they are affected by many factors besides iron stores.</p><p>Plasma iron has a marked diurnal & day to day variation & becomes very low during an acute phase response. </p><p>Levels of transferrin are lowered by malnutrition ,liver disease,acute phase response , & nephrotic syndrome.A transferrin saturation of less than 16%is consistent but is less specific than a ferritin measurement .</p><p>Reference : Davidson&;s principles & practice of medicine 22nd edition pg no-1023</p>