The blood urea nitrogen (BUN) test is done to measure the amount of nitrogen in your child’s blood. The nitrogen is present in a chemical called urea. Urea is a waste product made by the body when your child digests food. Urea is carried by the blood to the kidneys, which filter the urea out of the blood and into the urine.
This test is done to see how well your child’s kidneys are filtering waste from the body. This test can help diagnose and check treatment of kidney disease.
Some medicines are processed by the kidneys and can cause kidney damage as a side effect. The BUN test may be done to be sure your child has normal kidney function before your child starts taking these medicines.
This test is almost always done with another blood test called the creatinine test.
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.
Your child’s BUN level may be higher than normal because:
If your child is not sick, a BUN level lower than normal is, in general, not a cause for concern. If your child is sick, and 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: