An adult with arthritis has been receiving treatment with naproxen and now reports ongoing stomach pain, increasing weakness, and fatigue. Which laboratory test should the nurse monitor?

Choice A: Creatinine is not a relevant laboratory test for the nurse to monitor, as this reflects renal function and is not affected by naproxen or arthritis. This is a distractor choice. Choice B: Serum calcium is not a pertinent laboratory test for the nurse to monitor, as this indicates bone metabolism and is not related to naproxen or arthritis. This is another distractor choice. Choice C: Erythrocyte sedimentation rate is not an important laboratory test for the nurse to monitor, as this measures inflammation and is not influenced by naproxen or stomach pain. This is another distractor choice. Choice D: Hemoglobin is an essential laboratory test for the nurse to monitor, as this shows blood oxygen-carrying capacity and can be reduced by naproxen-induced gastrointestinal bleeding, which can cause stomach pain, weakness, and fatigue. Therefore, this is the correct choice.