The nurse is caring for a client who is taking diclofenac for rheumatoid arthritis. During a clinic visit, the client appears pale and reports increasing fatigue. Which of the client's serum laboratory values is most important for the nurse to review?

A. Hemoglobin: Diclofenac, a nonsteroidal anti-inflammatory drug (NSAID), can cause gastrointestinal bleeding leading to anemia. Pale appearance and fatigue are signs of anemia, making hemoglobin levels crucial to assess for blood loss or decreased oxygen-carrying capacity. B. Total protein: Total protein levels are not directly affected by diclofenac use and are less relevant to the symptoms of pallor and fatigue in this context. Monitoring protein is more related to nutritional status or liver function. C. Sodium: Sodium levels do not typically correlate with anemia symptoms or diclofenac adverse effects. While electrolyte imbalances can cause fatigue, the clinical presentation points more towards anemia. D. Glucose: Glucose levels are unrelated to the client’s symptoms and diclofenac therapy. Unless there is a known history of diabetes, glucose monitoring is not a priority here.