When the body breaks down a muscle component called creatine, a waste product called creatinine forms. In a healthy person, the kidneys remove the creatinine from the bloodstream and excrete it in the urine. Checking urine creatinine levels helps medical professionals diagnose some conditions and determine the best treatment options for their patients.
Identification
The 24-hour urine test helps to identify the amount of creatinine in the urine. This test method requires you to collect your urine in a special container for a 24-hour period and keep the container refrigerated when it is not in use. On the first morning of urine collection, you should urinate into the toilet as usual. Every additional time you urinate that day, you should use the collection container. On the morning of the second day of the test, you should urinate into the collection container. After this final collection, secure the lid of the container and take it to the laboratory for analysis.
Normal Range
The normal amount of creatinine in the urine ranges from 500 to 2,000mg per day. The normal amount for a person varies based on his lean muscle mass and age. Normal ranges also differ slightly from one laboratory to the next because of the different equipment and testing methods used. If you have a question about your results, ask your doctor to explain the normal range for your laboratory and review your results with you.
Significance
Doctors use this test to determine if a patient has normal kidney function. If urine has the normal amount of creatinine, it helps rule out disorders that affect the kidneys and reduce their ability to filter creatinine out of the bloodstream.
Abnormal Results
Abnormal amounts of creatinine in the urine may indicate kidney disorders or muscle-wasting diseases. These conditions include kidney failure, myasthenia gravis, obstruction of the urinary tract, kidney infection and reduced blood flow to the kidneys. Someone who follows a diet that contains a lot of meat may also have elevated urine creatinine levels.
Additional Testing
The creatinine clearance test uses the results of the urine creatinine test and a blood creatinine test to determine how well your kidneys filter waste products from the blood. After completing the 24-hour urine test, you give a blood sample so a laboratory technician can determine the amount of creatinine in your blood. After comparing the amount of creatinine in the urine with the amount of creatinine in the blood, the technician determines a creatinine clearance ratio. Normal results range from 97 to 137ml/min in men and 88 to 128ml/min in women.
