The concentration of a particular substance that is dissolved in the blood above which the substance is removed from the body in the form of urine is known as renal threshold.
The renal threshold of different substances varies as the ability to hold diferent substances varies by the kidney.
Along with the substance, the physiological conditions and the species also influence the renal threshold.
If the renal threshold for a substance is lowered then lower blood levels compounds will be excreted out and if the threshold is higher then opposite will occur.