Final answer:
Creatinine clearance is the test with the highest sensitivity for monitoring glomerular function, as it accurately reflects GFR by measuring the rate at which creatinine is filtered and excreted by the kidneys.
Step-by-step explanation:
In monitoring glomerular function, the creatinine clearance test has the highest sensitivity among the options provided. This test measures the glomerular filtration rate (GFR), which reflects the volume of fluid filtered from the renal glomerular capillaries into the Bowman's capsule per unit time. Creatinine, a waste product of muscle metabolism, is not significantly reabsorbed or secreted by the kidneys, making its clearance a good indicator of glomerular function. The creatinine clearance is calculated using a formula that incorporates urine creatinine concentration, urine flow rate, and plasma creatinine concentration, and is often corrected for body surface area.
Other tests such as blood urea nitrogen (BUN)/creatinine ratio are less sensitive due to urea's reabsorption and secretion dynamics. The urea clearance is less commonly used and can be influenced by factors like protein intake and liver function. Urine sodium is not a direct measure of GFR and therefore is not the most sensitive marker for glomerular function.