Creatinine in urine

Creatinine in the urine, also written as kreatinine.

With impaired kidney function, creatinine rises slightly, as supply remains the same while excretion decreases.

Creatinine is a breakdown product of creatine phosphate in muscle tissue. It is produced by our body in a fairly constant amount, depending on the amount of muscle mass present.

Creatinine is completely filtered out of the blood by the kidneys and excreted in the urine. This creates an equilibrium level in our blood. This equilibrium level is the result of the rate of production in the muscles and excretion by the kidneys. The concentration of creatinine in the blood and the excretion of creatinine in the urine together form a measure of the filtration capacity of our kidneys. This is also the measure of the amount of functioning kidney tissue as a whole.