A BUN is called blood,urea and nitrogen which is excreted from the kidney. It sounds like your kidney isn't properly removing toxins from the blood. Your Dr., will keep an eye on this. It doesn't mean your losing a kidney so don't worry about that. It can revert back and your Dr., will recheck it again.
My bun is 16 what does it mean?
My bun was 22 and my Creatine was normal. Does that indicate a significant problem