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 Values

Urine creatine (24-hour sample) values can range from 500 to 2000 mg/day. Results are highly dependent on your age and amount of lean body mass.

Note: Normal value ranges may vary slightly among different laboratories. 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 failure
• Muscular dystrophy (late stage)
• Myasthenia gravis
• Prerenal azotemia
• Pyelonephritis
• Reduced kidney blood flow (as in shock or congestive heart failure)
• Rhabdomyolysis
• Urinary tract obstruction

What the risks are

Special considerations

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References

Bazari H. Approach to the patient with renal disease. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 115.