【医】 血液尿素氮

BUN \BUN\ n. [acronym] (Med.)
same as

{blood urea nitrogen}; the concentration of nitrogen in blood
present in the form of urea; -- used as a measure of
kidney function.

Note: Blood usually contains 10 to 15 mg of nitrogen per 100
ml in the form of urea. --Stedman.
[PJC]