Which substance produced from skeletal muscle breakdown is commonly used to estimate renal function (GFR)?

Which substance produced from skeletal muscle breakdown is commonly used to estimate renal function (GFR)?

• A. Aldosterone
• B. Uric Acid
• C. Creatinine
• D. LDH

Answer: (C)

Creatinine is produced at a relatively constant rate from skeletal muscle metabolism and is cleared by the kidneys primarily through glomerular filtration. Because its production is stable and it is filtered (with little non-renal loss), the serum creatinine level closely tracks how well the kidneys are filtering the blood. Clinically, we use serum creatinine in equations (like CKD-EPI or MDRD) to estimate GFR, which provides a convenient measure of renal function and helps guide diagnosis and treatment. Aldosterone is a hormone that regulates salt and water balance, not a marker of filtration. Uric acid comes from purine metabolism and its levels are influenced by production, diet, and renal handling, so it’s not a direct reflection of GFR. LDH is an enzyme released from injured tissues and does not specifically indicate kidney filtration. Because of its stable production and direct relation to filtration, creatinine is the substance commonly used to estimate renal function.

Creatinine is produced at a relatively constant rate from skeletal muscle metabolism and is cleared by the kidneys primarily through glomerular filtration. Because its production is stable and it is filtered (with little non-renal loss), the serum creatinine level closely tracks how well the kidneys are filtering the blood. Clinically, we use serum creatinine in equations (like CKD-EPI or MDRD) to estimate GFR, which provides a convenient measure of renal function and helps guide diagnosis and treatment. Aldosterone is a hormone that regulates salt and water balance, not a marker of filtration. Uric acid comes from purine metabolism and its levels are influenced by production, diet, and renal handling, so it’s not a direct reflection of GFR. LDH is an enzyme released from injured tissues and does not specifically indicate kidney filtration. Because of its stable production and direct relation to filtration, creatinine is the substance commonly used to estimate renal function.