Algorithm for evaluation of chronic anemia based on the CBC (continued). Top box: “Low Hct/Hgb: Are reticulocytes increased?” is the same as the bottom right box in Figure 2. AIHA indicates autoimmune hemolytic anemia; AZT, azidothymidine; Cold Aggl., cold agglutinin disease; DAT pos., direct antiglobulin test (direct Coombs test) positive; DBA, Diamond-Blackfan anemia; GI, gastrointestinal; GU, genitourinary RBC, red blood cell; HS, hereditary spherocytosis; LDH, lactate dehydrogenase; MTX, methotrexate; PNH, paroxysmal nocturnal hemoglobinuria; PK, pyruvate kinase; PRCA, pure red cell aplasia; Tf sat.; transferrin saturation; and TMS, trimethoprim-sulfamethoxazole.