Blood Urea Nitrogen (BUN) Test

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Test Overview

A blood urea nitrogen (BUN) test measures the amount of nitrogen in your blood that comes from the waste product urea. Urea is made when protein is broken down in your body. Urea is made in the liver, Opens dialog and passed out of your body in the urine.

A BUN test is done to see how well your kidneys, Opens dialog are working. If your kidneys are not able to remove urea from the blood normally, your BUN level rises. Heart failure, Opens dialog, dehydration, Opens dialog, or a diet high in protein can also make your BUN level higher. Liver disease or damage can lower your BUN level. A low BUN level can occur normally in the second or third trimester, Opens dialog of pregnancy.

Blood urea nitrogen to creatinine ratio (BUN:creatinine)

A BUN test may be done with a blood creatinine, Opens dialog test. The level of creatinine in your blood also tells how well your kidneys are working—a high creatinine level may mean your kidneys are not working properly. Blood urea nitrogen (BUN) and creatinine tests can be used together to find the BUN-to-creatinine ratio (BUN:creatinine). A BUN-to-creatinine ratio can help your doctor check for problems, such as dehydration, that may cause abnormal BUN and creatinine levels.

Current as of: April 30, 2024

Author: Ignite Healthwise, LLC Staff

Clinical Review Board
All Ignite Healthwise, LLC education is reviewed by a team that includes physicians, nurses, advanced practitioners, registered dieticians, and other healthcare professionals.

Current as of: April 30, 2024

Author: Ignite Healthwise, LLC Staff

Clinical Review Board
All Ignite Healthwise, LLC education is reviewed by a team that includes physicians, nurses, advanced practitioners, registered dieticians, and other healthcare professionals.

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