A client with chronic renal failure (CRF) is admitted to the urology unit. Which diagnostic test results are consistent with CRF?

A client with chronic renal failure (CRF) is admitted to the urology unit. Which diagnostic test results are consistent with CRF?

• A. Blood urea nitrogen (BUN) 100 mg/dl and serum creatinine 6.5 mg/dl.
• B. BUN 10 mg/dl and creatinine 0.8 mg/dl.
• C. BUN 40 mg/dl and creatinine 0.9 mg/dl.
• D. BUN 9 mg/dl and creatinine 0.7 mg/dl.

Answer: (A)

When renal function declines, the kidneys can’t clear waste products effectively, so nitrogenous wastes accumulate in the blood. In chronic kidney disease, the glomerular filtration rate drops, leading to rising serum creatinine and, often, rising BUN as well. The test result showing a BUN of 100 mg/dL and a creatinine of 6.5 mg/dL represents marked elevation of both waste products, indicating severely reduced kidney clearance consistent with chronic renal failure. BUN can be influenced by factors like protein intake and hydration, so it’s less specific. Creatinine, produced at a relatively steady rate from muscle, is a more reliable indicator of GFR. The other value sets show either normal or only modest changes and don’t reflect the sustained impairment of filtration seen in chronic renal failure.

When renal function declines, the kidneys can’t clear waste products effectively, so nitrogenous wastes accumulate in the blood. In chronic kidney disease, the glomerular filtration rate drops, leading to rising serum creatinine and, often, rising BUN as well. The test result showing a BUN of 100 mg/dL and a creatinine of 6.5 mg/dL represents marked elevation of both waste products, indicating severely reduced kidney clearance consistent with chronic renal failure.

BUN can be influenced by factors like protein intake and hydration, so it’s less specific. Creatinine, produced at a relatively steady rate from muscle, is a more reliable indicator of GFR. The other value sets show either normal or only modest changes and don’t reflect the sustained impairment of filtration seen in chronic renal failure.