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Kidney Tests (KFT / RFT)

Phosphate (Phosphorus)

Phosphate is a mineral that works with calcium to build bones and is needed for energy production in cells.

Normal range (adults)
2.5–4.5 mg/dL (0.81–1.45 mmol/L)
Sample
Blood
Fasting
Not usually needed
Also called
Phosphorus, Serum Phosphate, Phosphorus Serum, PO4, Inorganic Phosphate, Phos

Phosphate normal range

Group mg/dLConventional units: US, South Asia mmol/LSI units: UK, Europe, Australia, international
Adults2.5–4.50.81–1.45

Your report may use either unit system; labs in the Gulf often print both. Ranges also vary slightly between laboratories, so the range printed on your own report is the one to go by.

Why is the Phosphate test done?

It is checked in kidney disease, bone disorders and parathyroid problems.

What does a high Phosphate level mean?

High phosphate is most often due to kidney disease. Over time it can weaken bones and harden blood vessels.

Common causes

  • Chronic kidney disease
  • Underactive parathyroid
  • Excess vitamin D
  • Phosphate-containing laxatives or enemas

Diet and lifestyle tips

  • If you have kidney disease, limit processed foods, cola drinks, processed cheese and processed meats, which contain added phosphate
  • Follow your dietitian's advice on dairy and protein portions
  • Take phosphate binders with meals if prescribed

What does a low Phosphate level mean?

Low phosphate can cause weakness and bone pain.

Common causes

  • Malnutrition or alcohol use
  • Vitamin D deficiency
  • Overactive parathyroid
  • Refeeding after starvation
  • Antacids containing aluminium

Diet and lifestyle tips

  • Eat protein foods: dairy, eggs, meat, fish, legumes
  • Correct vitamin D deficiency

When should you see a doctor?

Discuss abnormal phosphate with your doctor alongside calcium, vitamin D and kidney tests.

Last updated

This page is for general education and is not a diagnosis. Normal ranges differ between laboratories, so always compare your result with the reference range printed on your own report, and discuss abnormal results with your doctor.