24-Hour Urinary Phosphate Excretion Rate
This test measures how much phosphate (a mineral) your body excretes in urine over a 24-hour period. It helps assess kidney function and phosphate balance.
["This test helps evaluate kidney health and phosphate metabolism."]
Key facts at a glance
- LOINC
- 14881-7
- Short code
- Phosphate 24h Ur-sRate
- Synonyms
- Phosphate 24h Ur-sRate
- Category
- electrolyte
- Sample
- urine
- Container
- Sterile urine container
- Units
- N/A
- Ref low
- 2.5
- Ref high
- 4.5
- Critical range
- 1 N/A – —
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 84100
- Specimen volume
- 10 mL
- Stability
- Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
Why Is This Test Done?
Your doctor may order this test if they suspect kidney disease, phosphate disorders, or other conditions affecting how your body processes phosphate. It can also be used to monitor long-term kidney function or phosphate levels in certain chronic conditions.
What Does the Test Involve?
You’ll collect all your urine over a full 24-hour period, typically starting after waking up the morning of the test. Store the urine in a refrigerator until you return it to the lab. The lab will then analyze the total phosphate content in your urine sample.
What Are Common Causes of Testing?
Common reasons include evaluating kidney function, diagnosing phosphate disorders (such as hyperphosphatemia), assessing metabolic bone disease, or monitoring patients with chronic kidney disease or conditions like hyperparathyroidism.
What Do Results Typically Mean?
Results are not provided in absolute numeric ranges here, as they depend on individual health, diet, and kidney function. Your doctor will interpret the results in the context of your overall health and may compare them to your baseline or other test results.
Reference range
Adult: 2.5-4.5 mg/dLN/A
No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance: This test is critical for diagnosing and managing conditions affecting phosphate metabolism and kidney function. Elevated levels may indicate kidney disease or excessive phosphate intake, while low levels could suggest malabsorption or certain metabolic disorders. Your doctor will use these results to guide treatment plans.
Short name
24h Urine Phosphate
Frequently asked questions
How is this test different from a single urine phosphate test?
What should I do to prepare for this test?
Can I take medications before this test?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 17, 2026. · Read our editorial policy