What does having high phosurus serum in the blood mean?

Depending on level: Phosphorus is actually a very important mineral needed to make energy your body can use, but too high/low can cause trouble. Slightly high level may just be lab error. High dietary intake rarely cause high level if you don't have illness such as kidney disease. Renal failure is a common cause of high phosphorus, often needing regular use of phosphate binder medicine. Check with your doc. Good luck.