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Creatinine Blood Test

What is the creatinine blood test?

This test measures the level of creatinine in the blood. Creatinine is a waste product that is made when another chemical, creatine, is broken down to produce energy for the muscles. This waste product is carried by the blood to the kidneys, which filter it from the body into the urine.

Why is this test done?

This test may be done to see how well your child’s kidneys filter waste from the body. It can help diagnose kidney disease and see how well treatment is working. It may also be used to diagnose some muscle diseases.

How do I prepare for the test?

  • Your child’s healthcare provider may ask your child not to eat anything and to drink only water for awhile before the test. Follow their advice carefully.
  • Your child may need to avoid taking certain medicines before the test because they might affect the test result. Make sure your child’s healthcare provider knows about any medicines, herbs, or supplements that your child is taking. Ask your provider before stopping any of your child’s regular medicines.
  • Talk to your child’s healthcare provider if you have any questions about the test.

How is the test done?

Having this test will take just a few minutes. For babies, the heel may be pricked and a small amount of the blood is taken. For children, a small amount of blood is taken from a vein in your child’s arm with a needle. The blood is collected in tubes and sent to a lab.

This blood test may be done with a 24-hour urine test. It is done either right before you start to collect urine or the day you finish collecting urine.

Ask your child’s healthcare provider when and how you will get the result of your child’s test.

What does the test result mean?

Some of the reasons your child’s creatinine blood level may be higher than normal are:

  • Your child’s kidneys are not working well.
  • Your child has a kidney infection.
  • Your child has something blocking the flow of urine, such as a kidney stone.
  • Your child is dehydrated, or has not been drinking enough fluids to replace fluid lost through blood loss, sweat, or urine.
  • Your child has decreased blood flow to the kidneys.
  • Your child has muscle damage after a severe injury.
  • Your child is taking a medicine that affects your child’s creatinine level.

Your child’s creatinine blood level may be lower than normal if he has a disease that causes a loss of muscle tissue, such as myasthenia gravis or muscular dystrophy. It can also be low if your child does not eat enough protein or has lost a lot of weight.

What if my test result is not normal?

Test results are only one part of a larger picture that takes into account your child’s medical history, physical exam, and current health. Sometimes a test needs to be repeated to check the first result. Talk to your child’s healthcare provider about your child’s result and ask questions, such as:

  • If your child needs more tests
  • What kind of treatment your child may need
  • What lifestyle, diet, or other changes you might need to make
Developed by RelayHealth.
Pediatric Advisor 2015.3 published by RelayHealth.
Last modified: 2014-10-16
Last reviewed: 2014-10-16
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.
Copyright ©1986-2015 McKesson Corporation and/or one of its subsidiaries. All rights reserved.
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