Creatinine Test

This test measures creatinine levels in a sample of your blood and/or urine (pee). Creatinine is a normal waste product in your body. It's made when you use your muscles and some of the muscle tissue breaks down.

Normally, your kidneys filter creatinine from your blood and remove it from your body in your urine. If there is a problem with your kidneys, creatinine can build up in your blood and less may be released in urine. If blood and/or urine creatinine levels are not normal, it may be a sign of kidney disease.

Creatinine in blood may be measured by itself or as part of a group of tests called a comprehensive metabolic panel (CMP) or a basic metabolic panel (BMP). Your health care provider may order these tests as part of a routine checkup.

Why this test is done

Your provider may order a creatinine test:

• To check your kidney health as part of a routine checkup.
• If you have symptoms of kidney disease. Symptoms may include:
• Swelling in the hands and feet or puffy eyelids
• Dry skin, itching, or numbness
• Fatigue
• Increased or decreased need to urinate (pee)
• Urine that is bloody or foamy
• Loss of appetite and weight loss
• Muscle cramps
• Nausea and vomiting
• Shortness of breath
• Sleep problems
• Trouble thinking clearly
• If you have a high risk for developing kidney disease, even if you don't have symptoms now. Chronic (long-term) kidney disease (CKD) often doesn't have symptoms in the early stages. Your risk for kidney disease is increased if you:
• Have diabetes
• Have high blood pressure
• Have a family health history of kidney disease, diabetes, or high blood pressure
• Have heart disease
• Are over 50 years old
• Smoke
• Have obesity
• If you have kidney problems or possible kidney problems because you have:
• Had an abnormal result on a kidney test in the past
• Been diagnosed with kidney disease
• Taken certain medicines that could affect your kidneys
• Had a kidney transplant

How to prepare

Your provider will let you know how to prepare for your test. You may be told to not eat meat for 24 hours before your test. That's because meat can temporarily increase creatinine levels.

If creatinine is being measured as part of a CMP or a BMP test, you may need to fast (not eat or drink) for up to 12 hours before your test.

Certain medicines and supplements can affect your test results. So be sure to tell your provider everything you're taking. But don't stop taking any medicine unless your provider tells you to stop.

Sample type

Blood Urine

Other names for this test

blood creatinine, serum creatinine, urine creatinine, kidney function, renal function