Urine creatinine test
The creatinine urine test measures the amount of creatinine in urine. This test is done to see how well your kidneys are working.
Creatinine can also be measured by a blood test.
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 health care 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 provider.
How the Test will Feel
The test involves only normal urination. There is no discomfort.
Why the Test is Performed
Creatinine is a chemical waste product of creatine. Creatine is a chemical the body makes to supply energy, mainly to muscles.
This test is done to see how well your kidneys work. Creatinine is removed by the body entirely by the kidneys. If kidney function is not normal, creatinine level in your urine decreases.
This test can be used for the following:
- To 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 test results is:
- 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:
There are no risks with this test.
Inker LA, Fan L, Levey AS. Assessment of renal function. In: Johnson RJ, Feehally J, Floege J. Comprehensive Clinical Nephrology. 5th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 3.
Landry DW, Bazari H. Approach to the patient with renal disease. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 114.
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.