Which of the following should a nurse monitor in a client receiving insulin therapy?

Monitoring blood glucose levels in a client receiving insulin therapy is crucial because insulin is a key hormone used to regulate blood sugar. Insulin therapy is typically administered to manage hyperglycemia in conditions such as diabetes mellitus. By regularly checking blood glucose levels, the nurse can assess the effectiveness of the insulin regimen and avoid complications related to hypoglycemia or hyperglycemia. This monitoring allows for timely adjustments to the insulin dose if needed, ensuring that the patient's blood sugar remains within a safe and therapeutic range.

While heart rate, body temperature, and calcium levels may be important indicators of a patient's overall health and can be monitored in other contexts, they do not directly reflect the immediate effects of insulin therapy. Monitoring heart rate could help evaluate potential cardiovascular issues, while body temperature may indicate infection or inflammatory processes, and calcium levels are relevant in specific metabolic disorders or conditions affecting the parathyroid glands. However, in the context of insulin therapy, blood glucose levels are the primary focus to ensure proper diabetes management.