1. What other tests are used with BUN to check how my kidneys are functioning?
BUN and creatinine are the primary tests used to check how well the kidneys are able to filter waste products from your blood. Your doctor may also order electrolyte tests, such as sodium and potassium, or calcium to help understand how your kidneys are functioning.
BUN levels increase with age. BUN levels in very young babies are about 2/3 of the levels found in healthy young adults, while levels in adults over 60 years of age are slightly higher than younger adults. Levels are also slightly higher in men than women.
Occasionally, a doctor will look at the ratio between a person’s BUN and blood creatinine to help them determine what is causing these concentrations to be higher than normal. The ratio of BUN to creatinine is usually between 10:1 and 20:1. An increased ratio may be due to a condition that causes a decrease in the flow of blood to the kidneys, such as congestive heart failure or dehydration. It may also be seen with increased protein, from gastrointestinal bleeding, or increased protein in the diet. The ratio may be decreased with liver disease (due to decrease in the formation of urea) and malnutrition.
This article was last reviewed on November 29, 2012. | This article was last modified on February 24, 2015.
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