A nurse is reviewing the laboratory values of a client with bone marrow suppression and is receiving Oprelvekin. Which of the following values would indicate an improvement in the client's condition?

Bone marrow suppression leads to decreased production of blood cells, resulting in leukopenia, anemia, and thrombocytopenia depending on the affected cell line. Oprelvekin is a hematopoietic growth factor primarily used to stimulate platelet production in clients with chemotherapy-induced thrombocytopenia. It acts on bone marrow megakaryocyte progenitor cells to increase platelet formation and reduce bleeding risk. Improvement in therapy is best reflected by rising platelet counts toward the normal range. Rationale: A. A WBC count of 1,800 mm³ remains significantly below the normal range and indicates ongoing leukopenia. This level suggests continued bone marrow suppression and increased risk for infection. It does not reflect improvement in hematopoietic function or response to therapy. B. A WBC count of 3,500 mm³, while improved compared to severe leukopenia, is still below the normal range (typically 4,000–11,000 mm³). Although it may suggest partial recovery of white blood cell production, oprelvekin does not primarily target WBC production. Therefore, this is not the best indicator of therapeutic response. C. A hemoglobin level of 11.5 g/dL reflects mild anemia but is not directly related to the action of oprelvekin. This medication does not primarily stimulate red blood cell production but instead targets megakaryocyte proliferation. Hemoglobin improvement would be more relevant to erythropoietin therapy rather than oprelvekin. D. A platelet count of 150,000 mm³ indicates improvement into the lower limit of the normal range (150,000–450,000 mm³). This reflects effective stimulation of megakaryocyte activity by oprelvekin and improved bone marrow recovery. Since the drug is specifically used to increase platelet production, this value best demonstrates therapeutic effectiveness.