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Creatinine - urine
Definition
Creatinine is a breakdown product of creatine, which is an important part of muscle. Creatinine is removed from the body entirely by the kidneys. This article discusses the test done to measure the amount of creatinine in your urine.
A blood test can also be used to determine your creatinine level. See: Serum creatinine
Alternative Names
Urine creatinine test
How the Test is Performed
A random urine sample or a 24-hour collection may used. For information on how to collect a 24-hour urine sample, see: 24-hour urine collection.
How to Prepare for the Test
Your health care provider may tell you to temporarily stop taking certain medicines that may interfere with test results. Such medicines include:
- Cephalosporins (cefoxitin)
- Cimetidine
- Cisplatin
- Gentamicin
- Trimethoprim
How the Test Will Feel
The test involves only normal urination, and there is no discomfort.
Why the Test is Performed
This test can be used as a screening test to evaluate kidney function. It may also be used as part of the creatinine clearance test. It is often used to provide information on other chemicals in the urine such as albumin or protein.
Normal Results
Urine creatinine (24-hour sample) values can range from 500 to 2000 mg/day. Results depend greatly 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
The examples above are common measurements for results of these tests. 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 are nonspecific, but may be due to any of the following conditions:
- Glomerulonephritis
- High meat diet
- Kidney infection (pyelonephritis)
- Kidney failure
- Muscular dystrophy (late stage)
- Myasthenia gravis
- Prerenal azotemia
- Reduced kidney blood flow (as in shock or congestive heart failure)
- Rhabdomyolysis
- Urinary tract obstruction
References
Landry DW, Bazari H. Approach to the patient with renal disease. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 116.
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, Medical Director, A.D.A.M., Inc.
