Which laboratory examination is appropriate for evaluating a patient with kidney failure and CHF?

• A. Creatinine
• B. Theophylline level
• C. Urinalysis
• D. BUN

Answer: (A)

In the context of evaluating a patient with kidney failure and congestive heart failure (CHF), measuring creatinine levels is highly relevant. Creatinine is a waste product that is produced from muscle metabolism and is normally filtered out of the bloodstream by healthy kidneys. In kidney failure, the kidneys’ ability to filter creatinine decreases, leading to elevated levels in the blood. Thus, assessing serum creatinine levels provides important insight into kidney function and can help in diagnosing the severity of kidney damage.

Monitoring creatinine levels is essential in patients with CHF as well, since both conditions can influence each other. CHF can lead to renal impairment due to reduced renal perfusion, and impaired kidney function can exacerbate fluid overload and heart failure symptoms.

The other laboratory examinations, while useful in other contexts, do not provide direct insight into kidney function. Theophylline levels relate to a medication used for respiratory issues and are not relevant here, while urinalysis, while helpful for some kidney-related issues, does not directly measure kidney function as creatinine does. Blood Urea Nitrogen (BUN) is another marker that can indicate kidney function, but it is influenced by factors such as hydration status and protein intake, making it less specific compared to creatinine. Hence, creat