Anemia Diagnostic Algorithm Mean corpuscular (cell) volume (MCV): Average RBC size. Under 80 = microcytic. Between 80-95 (up to 100) = normocytic. Above 95 (or 100) is macrocytic. Red cell distribution width: Measures degree of variation among size of RBCs. Normal range 11.5% to 14.5%. Above 14.5% suggests wide range of RBC sizes. Reticulocyte count: Measures percentage of reticulocytes (immature RBCs) in peripheral blood. High in acute blood loss, hemolysis, exogenous erythropoietin (EPO), iron or B12 repletion. Low in bone marrow (BM) ablative disorders, lack of substrate (e.g. iron), low EPO, and conditions that impair erythropoiesis. Corrected reticulocyte count OR reticulocyte index above 2% suggests appropriate bone marrow response. If under 2%, then BM response insufficient for degree of anemia. Algorithm by Dr. Matthew Watto via @thecurbsiders podcast #Anemia #Algorithm #Diagnosis #Workup #Hematology #Microcytic #Macrocytic