Microcytic anemia

Reticulocyte count, ferritin, serum iron, TIBC, transferrin saturation

Reticulocyte count not elevated

Reticulocyte count elevated

Diagnosis: iron deficiency anemia

Serum iron decreased, ferritin decreased, % serum iron saturation decreased

Serum iron normal, ferritin normal, % serum iron saturation normal

Evaluate for occult blood loss

End

Diagnosis: β-thalassemia (trait or disease)

Perform hemoglobin electrophoresis

Hemoglobin electrophoresis and globin chain synthesis studies abnormal

Normal hemoglobin electrophoresis

Diagnosis: sideroblastic anemia

Diagnosis: heavy metal poisoning (lead, mercury, cadmium)

Diagnosis: anemia of chronic disease (inflammatory anemia)

Evaluate for infections, rheumatologic or malignant disease

Evaluation for inherited red cell membrane defects

Abnormal red cell forms (nonspherocytes) on peripheral blood smear

Spherocytes on peripheral blood smear

Diagnosis: hereditary spherocytosis

Diagnosis: autoimmune hemolytic anemia

Blood lead level, urine heavy metal screen

High lead level, urine heavy metal screen positive

Normal lead level, urine heavy metal screen negative

Bone marrow aspirate

Bone marrow aspirate has ringed sideroblasts

Bone marrow aspirate does not have ringed sideroblasts

Direct antiglobulin (Coombs) test positive

Direct antiglobulin (Coombs) test negative