Iron deficiency anemia (IDA) develops through three progressive stages: (1) iron depletion—reduced ferritin stores with normal hemoglobin; (2) iron-deficient erythropoiesis—low serum iron, elevated TIBC, reduced transferrin saturation (<20%), with early microcytosis; (3) iron deficiency anemia—low hemoglobin with microcytic, hypochromic RBCs and elevated RDW. The body absorbs dietary iron primarily in the duodenum via divalent metal transporter-1 (DMT1), with hepcidin acting as the master regulator of iron homeostasis. The nurse performs comprehensive assessment, interprets laboratory trends, manages transfusion therapy for severe cases, administers IV iron infusions, monitors for adverse reactions, and provides individualized patient education.