Now, one example of such a substance is urea. Urea is small enough to actually filter easily through our glomerulus, but a small percentage of it is actually reabsorbed. In fact, 60 ML/minute is reabsorbed, and that means 125 gives us about 65 ML/minute. So this is the renal clearance of urea. This is how much volume of blood plasma is cleared of urea every single minute by the nephron of our kidney. Now, there are other cases that exist.