Progressive Care Nursing Certification (PCCN) Practice Exam

Which lab test is usually affected by renal function when cyclosporine is used?

1. Serum sodium

2. Serum potassium

3. Serum creatinine

4. Serum glucose

The correct answer is: Serum creatinine

When considering the impact of cyclosporine on renal function, serum creatinine is particularly significant. Cyclosporine is an immunosuppressant medication often used in transplant patients and for autoimmune conditions. It can cause nephrotoxicity, which refers to damage to the kidneys. This damage can lead to an elevation in serum creatinine levels, which serves as a key marker for assessing renal function. Creatinine is a waste product formed from muscle metabolism, and its levels in the blood provide insight into how well the kidneys are filtering out waste. When renal function declines, as can occur with cyclosporine usage, creatinine clearance decreases, resulting in elevated serum creatinine levels. Monitoring this lab value is essential for clinicians in managing the medication's effects and ensuring patient safety. While serum sodium, serum potassium, and serum glucose can also be influenced in various ways by medications and health conditions, they are not as directly affected by cyclosporine in relation to renal function as serum creatinine. Changes in electrolytes can occur but are typically more associated with other factors or medications. Thus, serum creatinine is the most relevant lab test in the context of renal function when cyclosporine is being used.