Source:http://linkedlifedata.com/resource/umls/id/C0600137
NCI: Nitrogen in the blood that comes from urea (a substance formed by the breakdown of protein in the liver). The kidneys filter urea out of the blood and into the urine. A high level of urea nitrogen in the blood may be a sign of a kidney problem.,NCI: The most prevalent of nonprotein nitrogenous compounds circulating in the blood used as an indicator of liver and kidney function.