Which combination of tests is used to assess renal function in anesthetic patients with renal disease?

• A. USG, BUN, Creatinine, and SDMA
• B. USG, BUN, and Creatinine
• C. SDMA alone
• D. BUN and Creatinine

Answer: (A)

In evaluating renal function for anesthesia planning, you want both what the kidneys look like and how well they’re filtering. Ultrasound (USG) gives a view of anatomy—kidney size, structure, and potential obstruction—so you can detect issues that might affect drug handling or urine flow. BUN and creatinine are the classic functional tests that reflect filtration in real time, but each has limitations: creatinine can be influenced by muscle mass and hydration, and BUN can be affected by protein intake and volume status. SDMA is a newer marker that tends to rise earlier than creatinine and is less influenced by muscle mass, making it a sensitive indicator of reduced glomerular filtration. Using all four together—USG for structure, BUN and creatinine for function, plus SDMA for early detection—provides the most complete picture of renal status in a patient with renal disease, which is essential for safe anesthetic drug dosing, fluid management, and planning. The other options lack either the imaging component or the early/function markers, or rely on a single approach, so they don’t provide as comprehensive an assessment.