What does BUN mean?

BUN stands for Blood Urea Nitrogen. Nitrogen is an essential element of amino acids, which are the building blocks of protein.

When we eat protein-rich food, it is broken down by our digestive system into amino acid. This amino acid has 1 of 2 fates: It is either used to make protein for muscle formation, or the liver degrades it into urea.

Urea is a compound that contains nitrogen; once produced, it is excreted into the urine. Kidney failure causes Blood Urea Nitrogen (BUN) to increase.

Causes of High BUN

High protein diet
Gastrointestinal bleeding

Causes of Low BUN

Low protein diet
Liver disease