serumfosfat

Serumfosfat is the concentration of inorganic phosphate in blood serum or plasma. It reflects dietary phosphate intake, bone metabolism, and renal excretion, and is commonly measured as part of routine metabolic testing or kidney function assessment.

Phosphorus plays several essential roles in the body. It is a component of adenosine triphosphate (ATP) and nucleotides, participates in cellular signaling, and is critical for bone mineralization as part of hydroxyapatite. It also contributes to acid–base balance and energy metabolism.

Regulation of serumfosfat is mainly achieved by the kidneys, which adjust phosphate reabsorption in the proximal tubule. Hormones such as parathyroid hormone (PTH), vitamin D (calcitriol), and fibroblast growth factor 23 (FGF23) modulate renal handling of phosphate. The balance among intake, absorption, and excretion determines the serum level, which can shift between intracellular and extracellular compartments under certain conditions.

Measurement and reference values: serumfosfat is typically reported in millimoles per liter (mmol/L) or milligrams per deciliter (mg/dL). In healthy adults, a common reference range is about 0.8–1.4 mmol/L (2.5–4.5 mg/dL), though exact ranges vary by age, laboratory, and method. Pediatric values and pregnancy can differ, and levels may be affected by recent meals, hydration, and medications.

Clinical significance: abnormal serumfosfat levels can indicate disorders of bone and mineral metabolism or kidney function. Hyperphosphatemia commonly occurs in chronic kidney disease, hypoparathyroidism, and certain treatments or cell lysis, while hypophosphatemia can result from malnutrition, refeeding syndrome, alcohol use, insulin therapy, or certain medications. Phosphate levels are interpreted alongside calcium, PTH, vitamin D, and renal function to assess bone health and mineral balance.