For most types of cancer, a biopsy is the main way doctors diagnose cancer. A biopsy is the removal of a small amount of tissue for examination under a microscope. Other tests can suggest that cancer is present, but only a biopsy can make a definite diagnosis. Your doctor may recommend a biopsy if something suspicious is found during a physical exam or another test.
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.
Blood urea nitrogen (BUN) test. Overview. A common blood test, the blood urea nitrogen (BUN) test reveals important information about how well your kidneys and liver are working. A BUN test measures the amount of urea nitrogen that's in your blood. 1  Your liver produces ammonia â which contains nitrogen â after it breaks down proteins used by your body's cells.  The nitrogen combines with other elements, such as carbon, hydrogen and oxygen, to form urea, which is a chemical waste product.