Phosphate in Urine
Reviewed
This test measures the amount of phosphate in urine collected over 24 hours. Phosphate contains phosphorus, an electrolyte that helps build bones, make energy, and support nerve and muscle function. The kidneys and intestines control phosphate levels, which are linked to calcium, vitamin D, and parathyroid hormone. The test helps evaluate kidney function, parathyroid disorders, and causes of kidney stones.
Preparation and collection
No special preparations needed. Follow all instructions for collecting a 24-hour urine sample.
Understanding this test
Use the reference interval and units printed by the laboratory that performed the test. A result outside that interval is not a diagnosis by itself, and a result inside it does not rule out every condition. Your symptoms, history, medicines, timing, and related tests can change what the result means.
- Results are interpreted by your healthcare provider based on your overall health, symptoms, and other test results.
- Abnormal levels do not always mean a medical condition that needs treatment.
- Diet (high-phosphorus meal) and medications (laxatives with sodium phosphate) can affect results.
- Children often have higher phosphate levels because their bones are still growing.
What to do next
If your results are not normal, talk with your provider to understand what they mean for your health. Your provider may recommend additional tests, such as a blood phosphate test, to get a complete picture.