Creatinine - urine
The urine creatinine test measures the amount of creatinine in urine.
Creatinine is a breakdown product of creatine, which is an important part of muscle. Creatinine is removed from the body entirely by the kidneys. Creatinine can also be measured by a blood test.
Urine creatinine test
How the Test is Performed
After you provide a urine sample, it is tested in the lab. If needed, your doctor may ask you to collect your urine at home over 24 hours. Your provider will tell you how to do this. Follow instructions exactly so that the results are accurate.
How to Prepare for the Test
Your health care provider may tell you to temporarily stop taking certain medicines that may affect test results. Be sure to tell your provider about all the medicines you take. These include:
- Antibiotics, such as cefoxitin or trimethoprim
Do not stop taking any medicine before talking to your doctor.
How the Test will Feel
The test involves only normal urination. There is no discomfort.
Why the Test is Performed
This test can be used for the following:
- Evaluate how well the kidneys are working
- As part of the creatinine clearance test
- To provide information on other chemicals in the urine, such as albumin or protein
Urine creatinine (24-hour sample) values can range from 500 to 2000 mg/day. Results depend on your age and amount of lean body mass.
Another way of expressing the normal range for these test results are:
- 14 to 26 mg per kg of body mass per day for men
- 11 to 20 mg per kg of body mass per day for women
Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your doctor about the meaning of your specific test results.
What Abnormal Results Mean
Abnormal results of urine creatinine may be due to any of the following:
- High meat diet
- Kidney problems, such as damage to the tubule cells
- Kidney failure
- Too little blood flow to the kidneys, damage to filtering units
- Kidney infection (pyelonephritis)
- Muscle breakdown (rhabdomyolysis), or loss of muscle tissue (myasthenia gravis)
- Urinary tract obstruction
There are no risks with this test.
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Israni AK, Kasiske BL. Laboratory assessment of kidney disease: glomerular filtration rate, urinalysis, and proteinuria. In: Taal MW, Chertow GM, Marsden PA, et al., eds. Brenner and Rector’s The Kidney. 9th ed. Philadelphia, Pa: Elsevier Saunders; 2011:chap 25.
McPherson RA, Ben-Ezra J. Basic examination of urine. In: McPherson RA, Pincus MR, eds. Henry’s Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. Philadelphia, Pa: Elsevier Saunders; 2011:chap 28.
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial team.