GFR = ClearanceCR = Urine Cr x Urine Flow / Plasma Creat
Increased muscle mass ---> Increased Plasma Cr! Now if you do the old 24 hr method of collecting urine , you will see that Urine Cr increases too so it will be accurate .. But if you use the equations that you just put the Plasma Cr , they will obviously underestimate the GFR ( e.g bodybuilder may have 2.0 mg/ml serum Cr , which puts him in renal failure range , but actually he has no kideny problem at all)
Appreciate that this is the Calculated GFR only , in reality muscle mass by itself will not change the actual GFR
Last edited by tassosant13; 10-25-2015 at 03:16 AM.