Phosphorus
A mineral that partners with calcium to build bone and is central to cellular energy.
| Typical reference range | 2.5–4.5 mg/dL |
Ranges vary by laboratory, method, age and sex: always use the range printed on your own report. Why labs differ.
What it measures
Phosphate is a component of bone, DNA, cell membranes and ATP. Blood levels are regulated by the kidneys, parathyroid hormone, vitamin D and the hormone FGF23.
Why it matters
Abnormal phosphate is a key marker in kidney disease and bone-mineral disorders and helps interpret abnormal calcium and PTH.
What a high result can mean
High phosphate is most often due to chronic kidney disease. Other causes include hypoparathyroidism, excess vitamin D, tissue breakdown and sample hemolysis.
What a low result can mean
Low phosphate can occur with hyperparathyroidism, vitamin D deficiency, malnutrition, alcohol use disorder, refeeding after starvation, antacid overuse and some IV iron preparations.
What affects the result
Levels are higher in children and fall slightly after carbohydrate-rich meals; fasting morning samples are most consistent. Interpret with calcium, PTH, vitamin D and kidney function.
Units and conversion
Usually reported in mg/dL.
- From mmol/L: multiply by 3.097 to get mg/dL
Also called on lab reports
Phosphate, Phosphorus, Inorganic, Phos, Inorganic Phosphate, Phosphorus, Serum
Related tests: Electrolytes & Minerals
This page is educational and does not replace advice from a healthcare professional.