The phosphorus test measures the level of phosphorus in your blood. Phosphorus is a common mineral found in the food you eat. It's also found in teeth and bones.
Having a high or low level of phosphorus in your bloodstream can signal several health conditions. Most commonly, a high level of phosphorus is related to a kidney disorder. It shows that your kidneys are having difficulty clearing phosphorus from your blood. A high level of phosphorus can also mean uncontrolled diabetes and other endocrine disorders.