Family Nurse Practitioner Exam

Which laboratory test is most commonly used to evaluate renal function?

1. Electrolyte panel

2. Creatinine

3. Alkaline phosphatase

4. Blood urea nitrogen (BUN) to creatinine ratio

The correct answer is: Creatinine

The most commonly used laboratory test to evaluate renal function is creatinine. Creatinine is a waste product that is produced from normal muscle metabolism and is typically filtered out of the blood by the kidneys. Measuring serum creatinine levels provides a direct indication of the kidneys' ability to filter waste from the bloodstream. Elevated levels of creatinine can indicate impaired kidney function, making it a critical marker for assessing renal health. While other tests like the blood urea nitrogen (BUN) test can also reflect renal function, creatinine is generally preferred due to its stability and because it is less affected by factors such as hydration status and protein intake. The electrolyte panel provides information on the balance of electrolytes and may indicate kidney function but is not a direct measure of renal health. Alkaline phosphatase primarily reflects liver and bone function, not renal function. Therefore, creatinine remains the standard marker for evaluating kidney performance.