Creatinine is a waste product formed by the breakdown of a
substance (creatine) important for converting food into energy (metabolism).
The creatinine is filtered out of the blood by the kidneys and then passed out
of the body in urine.
If the kidneys are damaged and can't
function normally, the amount of creatinine in the urine decreases while the
amount of creatinine in the blood increases.
E. Gregory Thompson, MD - Internal Medicine & Adam Husney, MD - Family Medicine & Michael Mallea, MD - Nephrology