I have neprhocalcinosis, today I had a renal function test done and my BUN was 7 & chloride 112, other levels normal. What could this mean?

Labs. Your BUN is lower and maybe a reflection of your protein intake but doesn't mean disease. BUN levels are governed by many reasons including kidney function protein intake liver issues. Assuming you have no issue low BUN is more diet. Your chloride is high normal and should hair be repeated. These labs have to be looked in totality and don't mean disease. Best of luck .
Nephrocalcinosis. It could mean that you are making and excreting small and/or large kidney stones even though your labs are normal. Please get some more information from your doctor about any kidney issues.