Mean ANC, hemoglobin (Hb) concentration, and platelet count (PLT). Hemoglobin declined 4% to 5% between weeks 5 and 9 after RIT, and ANC decreased 17% to 24% between weeks 5 and 8 after RIT. Mean platelet count declined from 2.5 × 10⁶/L at baseline to less than 0.8 × 10⁶/L at weeks 4 to 5 after RIT. Complete differential blood and platelet counts were obtained before ⁹⁰Y-ibritumomab administration and weekly thereafter for 12 weeks.