This test measures amount of phosphorus in blood. Phosphorus is essential for the metabolism of protein, calcium, and glucose. The body uses phosphorus in its combined forms, which are obtained from such nutritional sources as milk, cheese, meat, egg yolk, whole grains, legumes, and nuts. A nutritional deficiency of phosphorus can cause weight loss, anemia, and abnormal growth. Elemental white or yellow phosphorus is extremely poisonous and produces severe GI irritation. If ingested, it can produce hemorrhage, cardiovascular failure, and death. Chronic poisoning by phosphorus is characterized by anemia, cachexia, bronchitis, and necrosis of the mandible. Normal adult blood levels of phosphorus are 3 to 4.5 mg/dL or 0.97 to 1.45 mmol/L (SI units). Phosphorus tests are most often ordered along with other tests, such as those for calcium, parathyroid hormone (PTH), and/or vitamin D, to help diagnose and/or monitor treatment of various conditions that cause calcium and phosphorus imbalances. Abnormal phosphorus levels indicates kidney, liver, and certain bone diseases .