It is done as per Photometry method: Technology:kinetic UV Assay

Any foods that act as a liver and kidney detoxifier. Read up on how Nitrogen breaks down. l believe it goes nitrogen, nitrites, nitrates into ammonium, then urea. Not sure, though. Point being, that it is good to clear the liver and kidneys of excess toxins, thereby allowing the body is normal metabolism a better chance at self-balancing. Hope it helps.

A slight elevation of the BUN could just be mild dehydration. l do not think it requires a change of diet, but certainly increase fluid intake.