Ideal substance for measuring GFR should have all characteristics except
The Ideal substance to measure GFR is Inulin or following reasons ; It is non-toxic; It is freely filterable by the glomeruli; it is not bound to proteins It is neither secreted nor reabsorbed by the tubules; It is not synthesized, stored, or destroyed by the kidney . Thus, Filtered inulin = excreted inulin .Hence, it will give an exact estimate of the GFR. Endogenous creatinine clearance is used most commonly used to estimate the GFR.
Should be secreted in tubules
Should be non-toxic
Should not remain in the body
Should not be protein bound
Excretory System (Kidney, Bladder) Acid-Base Balance