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.
What Is a Blood Urea Nitrogen Test? A blood urea nitrogen (BUN) test checks kidney function by measuring how much urea nitrogen is in your blood. Urea nitrogen is a waste product from the breakdown of protein in the body. Normally, this waste is filtered by the kidneys and leaves the body through urine.