Phosphorus

Serum Phosphorus (Phosphate) measures inorganic phosphate levels in the blood. Phosphorus is essential for bone structure (hydroxyapatite), energy transfer (ATP), DNA/RNA structure, and cell membranes. Levels are regulated by the kidneys, PTH, and vitamin D, often in inverse relationship with calcium. High levels (hyperphosphatemia) are common in kidney failure or with excessive intake/low PTH. Low levels (hypophosphatemia) can occur with malnutrition, refeeding syndrome, high PTH, or vitamin D deficiency.