Creatinine is a waste product created when muscles metabolize. Healthy kidneys clear creatinine and other waste out of blood. The body gets rid of waste in urine. A creatinine test checks kidney function by measuring the amount of creatinine in either blood or urine.

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What is a creatinine test?

A creatinine blood test measures creatinine levels in your blood to see if your kidneys are working well. High creatinine levels in blood indicate that kidneys are not filtering waste like they should.

A creatinine urine test, or creatinine clearance test, measures creatinine in your urine. Both tests are sometimes used together to assess kidney health.

Your healthcare provider may order creatinine tests if you have:

  • Diabetes (recommended at least once a year)
  • Kidney disease (recommended regularly)
  • An illness that could affect a kidney

Why is a creatinine test important?

Healthy kidneys are essential for life. Creatinine tests monitor the health of your kidneys. High creatinine levels may indicate:

  • Kidney damage or disease
  • Problems with muscle metabolism
  • Problems with the urinary tract
  • Dehydration

Low creatinine levels may indicate:

  • Malnutrition
  • Loss of muscle mass

Normal creatinine levels vary between women and men, and they can vary among different labs. Ask your healthcare provider to explain your results.

What should you expect with a creatinine test?

For a creatinine blood test, a healthcare provider uses a needle to draw a blood sample, typically from a vein in your arm. A creatinine urine test requires a urine sample. You will urinate into a sterile cup to collect a sample. You may also be asked to collect your urine during a 24-hour period. Your provider will give more specific instructions on how to collect a clean sample. Samples are sent to a lab for analysis.

No preparation is needed for either test, but you should give your healthcare provider a list of medications you are taking. Certain drugs affect creatinine levels. Ask your healthcare provider to explain your results.

If are experiencing symptoms that suggest kidney damage, contact the nearest CareNow® urgent care clinic for testing. You can minimize your wait time with our Web Check-In®.

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