Hyperphosphatemia's an electrolyte disturbance in which there's an abnormally elevated level of phosphate in the blood. Often, calcium levels are lowered (hypocalcemia) due to precipitation of phosphate with the calcium in tissues. Causes Hypoparathyroidism: In this situation, there're low levels of PTH. PTH normally inhibits renal reabsorption of phosphate, and so without enough PTH there's more reabsorption of the phosphate. Chronic renal failure: When the kidneys aren't working well, there'l… (More on Hyperphosphatemia)