A love affair with cigars is like most affairs of the heart. We swoon over the beauty and elegance, but we never really know what makes us love--and we don't want to. To overanalyze a cigar, or a mate, is to destroy the mystery.
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 and passed out of your body in the urine. A BUN test is done to see how well your kidneys are working.
Updated April 19, 2016. Blood urea nitrogen - BUN - is a blood test performed as a marker of kidney function. It is part of the basic metabolic panel done for health screening. It is also used to monitor the progression of kidney failure. BUN is produced by the breakdown of protein and usually cleared from the blood by the kidneys.