The blood urea nitrogen (BUN) test is a common test to check how well your child’s kidneys are working. It measures the amount of urea nitrogen in your child’s blood. Nitrogen is a chemical made by the body when food is digested. It combines with other things to form urea, which is body waste that is carried by the blood to the kidneys. The kidneys filter the urea nitrogen out of the blood and into the urine.
This test is done to help diagnose kidney problems or to check how well treatment of kidney disease is working.
Some medicines are processed by the kidneys and can cause kidney damage as a side effect. Some medical conditions can also cause kidney damage. The BUN test may be done to be sure your child has normal kidney function before she starts taking these medicines or to check the effect of her medical condition on her kidneys.
This test is almost always done with another test called the creatinine test. 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.
Your child may need to avoid taking certain medicines before the test because they might affect the test result. Make sure your 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.
Having this test will take just a few minutes. A small amount of blood is taken from a vein in your child’s arm with a needle. In younger children, this test can be done with a finger prick or heel stick.
Ask your child’s healthcare provider when and how you will get the result of your child’s test.
Your child’s BUN level may be higher than normal because:
If your child is not sick, a BUN level lower than normal is usually not a cause for concern. If the BUN is lower than normal, it may mean:
Test results are only one part of a larger picture that takes into account your child’s medical history and current health. Sometimes a test needs to be repeated to check the first result. Talk to your child’s health care provider about your child’s result and ask questions, such as: