Creatinine normally occurs in urine. It is a by-product of creatine, which is found in muscles and indicates how well the kidneys work, according to MedlinePlus. Creatinine is removed from the body via the kidneys and is measured through a urine or blood test.
The normal range for urine creatinine in a 24-hour sample ranges from 500 to 2,000 milligrams per day, claims MedlinePlus. The results depend on the person's age and gender and how much lean body mass the person has. Test results may also be expressed per body mass. Men should have 14 to 26 milligrams of creatinine per kilogram of body mass per day, and women should have 11 to 20 milligrams of creatinine per kilogram of body mass per day.
Abnormally high urine creatinine test results may occur if the person consumes large quantities of meat, so a patient should inform his doctor if this is the case, states MedlinePlus. Other causes for high levels of creatinine usually indicate kidney issues, such as tubule cell damage. Kidney failure may be present in a person with high levels of creatinine, or there may be too little blood getting to the kidneys. Kidney infections, the breakdown or loss of muscle, and urinary tract obstruction may also cause high levels of creatinine in the urine.