Diagnostic Approach to Anemia

Initial Evaluation

The peripheral blood smear with reticulocyte count serves as a critical initial diagnostic tool to differentiate between decreased red blood cell production versus increased destruction/loss, while simultaneously identifying specific morphologic abnormalities that point toward underlying hematologic disorders, as recommended by the American College of Physicians 1
The National Comprehensive Cancer Network (NCCN) guidelines mandate a comprehensive panel, including complete blood count with differential, reticulocyte count, and peripheral blood smear examination, for evaluating suspected hematologic disorders 4, 5

The reticulocyte count is useful for estimating red cell production and determining whether the bone marrow is responding appropriately to anemia, with an inappropriately low reticulocyte count suggesting bone marrow failure or nutritional deficiency, according to the American Society of Hematology 2
In pyruvate kinase deficiency, the reticulocyte count may be inappropriately low relative to the degree of hemolysis, but rises dramatically post-splenectomy, as noted by the American Journal of Hematology 2

The peripheral smear examination provides direct visualization of red blood cell abnormalities, including size variations, shape abnormalities, and color/hemoglobinization, which can indicate specific anemia types or underlying hematologic disorders, as described by the College of American Pathologists 1
The presence of erythroblasts or immature myeloid cells in peripheral blood can indicate severe hemolysis, ineffective erythropoiesis, or myelodysplastic syndromes, according to the International Society for Laboratory Hematology 2, 3

The peripheral smear and reticulocyte count guide the decision for bone marrow biopsy, which is recommended for unexplained persistent cytopenias, dysplastic features on smear, presence of blasts, or reticulocytopenia without clear cause, as suggested by the National Comprehensive Cancer Network (NCCN) 4, 6
Bone marrow assessment includes cellularity, blast percentage, dysplasia evaluation, iron staining for ringed sideroblasts, and cytogenetics, as recommended by the American Society of Clinical Oncology 4, 6