I got Nao's test results. BUN and creatinine were a tad high but nothing too alarming. I'll be sticking with the Purina Urinary Tract Health flavors that are low on phosphorus; the fish flavor that he likes is high on phosphorus so I'm going to feed him that one less, like once a month or something.
He also has a slight infection going on, on his mouth. He'll start a course of antibiotics on Monday. The dental cleaning is scheduled to be on Thursday.