Serum phosphorus reference range
| Group | Normal Range |
|---|---|
| Adults | 2.5–4.5 mg/dL (0.81–1.45 mmol/L) |
| Children | 4.0–7.0 mg/dL (higher due to growth) |
| High (hyperphosphataemia) | >4.5 mg/dL in adults |
| Low (hypophosphataemia) | <2.5 mg/dL |
High phosphorus (hyperphosphataemia)
Kidney disease and phosphorus
The kidneys excrete excess phosphorus. In chronic kidney disease (CKD), the kidneys lose this ability, causing phosphate to accumulate. High phosphorus in CKD accelerates bone disease (renal osteodystrophy) and calcification of blood vessels and soft tissues — a major contributor to cardiovascular death in dialysis patients. Hyperphosphataemia is also seen in hypoparathyroidism, vitamin D toxicity, and rhabdomyolysis.
Low phosphorus (hypophosphataemia)
| Cause | Mechanism |
|---|---|
| Malnutrition / refeeding syndrome | Glucose infusion drives phosphate into cells |
| Hyperparathyroidism | PTH causes kidneys to excrete phosphate |
| Vitamin D deficiency | Reduces intestinal phosphate absorption |
| Antacid overuse | Aluminium antacids bind phosphate in the gut |
| Alcoholism | Poor intake + increased urinary losses |
Questions to ask your doctor
- Is my high phosphorus related to kidney disease?
- Do I need a phosphate binder medication?
- Is my calcium level also abnormal?
Medical Disclaimer: For educational purposes only. Always consult a qualified healthcare professional for diagnosis and treatment.