Hematologic System

Microcytic (low MCV), hypochromic anemia with low ferritin — ferritin is the most specific marker of depleted iron stores. Serum iron and transferrin saturation fall while TIBC (transferrin) rises.

Evaluate for GI blood loss with colonoscopy and/or upper endoscopy — occult GI malignancy must be excluded before attributing it to diet.

A low reticulocyte count (low reticulocyte production index) means marrow underproduction (iron/B12 deficiency, aplastic, chronic disease). A high reticulocyte count means the marrow is responding to hemolysis or acute blood loss.

Oral ferrous sulfate; absorption improves with vitamin C / acidic environment and is reduced by food, antacids, and PPIs. Common GI side effects (constipation, dark stools); alternate-day dosing may improve tolerance and absorption.

Mentzer index = MCV ÷ RBC count. <13 suggests thalassemia trait (normal/high RBC count, very low MCV); >13 suggests iron deficiency. Thalassemia also shows normal/high ferritin and an elevated RBC count.