This document provides an overview of anemia, including its definition, causes, evaluation, and treatment. It begins with defining anemia based on hemoglobin levels and describes normal erythropoiesis. The document then outlines the steps to take in a history and physical exam when evaluating a patient for anemia. It reviews various lab tests that can help classify anemia and identifies the approach for different types based on red blood cell indices. Peripheral blood smear findings are also reviewed. The document concludes with discussing anemia in the context of pancytopenia and interpreting reticulocyte counts.