A nurse is caring for a client with bone marrow suppression due to methotrexate therapy. Which laboratory value should the nurse monitor to assess for the improvement of the client's condition?

Bone marrow suppression is a common adverse effect of cytotoxic and antimetabolite therapies such as Methotrexate. This condition results in decreased production of blood cells, leading to anemia, leukopenia, and thrombocytopenia. Because the bone marrow is responsible for hematopoiesis, monitoring blood cell counts is essential to evaluate recovery and detect toxicity early. Improvement is primarily reflected in normalization of circulating blood cell lines. Rationale: A. A complete blood count (CBC) is the most appropriate laboratory test to monitor improvement in bone marrow suppression. It directly measures white blood cells, red blood cells, hemoglobin, hematocrit, and platelets, all of which are affected by methotrexate toxicity. Rising counts toward normal ranges indicate recovery of bone marrow function and improved hematopoiesis. B. Renal function tests are important in clients receiving methotrexate because the drug is primarily excreted by the kidneys and can accumulate in renal impairment. However, these values assess drug clearance and toxicity risk rather than recovery from bone marrow suppression. They do not directly reflect improvement in blood cell production. C. Liver function tests (LFTs) are monitored because methotrexate can cause hepatotoxicity with prolonged use. While they help detect liver injury, they are not indicators of bone marrow recovery. Improvement in bone marrow function is not reflected in hepatic enzyme levels. D. Blood chemistry panels assess electrolytes and metabolic status, which may be indirectly affected in critically ill patients. However, they do not provide specific information about bone marrow activity or hematologic recovery. Therefore, they are not useful for evaluating improvement in bone marrow suppression.