Phosphorus concentration in serum or plasma
This test measures the amount of phosphorus, an essential mineral, in your blood. Phosphorus helps maintain healthy bones and teeth and is important for energy production in your body.
["Phosphorus levels can help doctors assess kidney function and metabolic health."]
Key facts at a glance
- LOINC
- 2778-9
- Short code
- Phosphate Ur-mCnc
- Synonyms
- Phosphate Ur-mCnc
- 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 This Test Might Be Ordered
Your healthcare provider may order this test if they suspect kidney disease, metabolic disorders, or other conditions affecting phosphorus balance. It can also be part of routine check-ups for patients with chronic conditions like diabetes or heart disease.
What to Expect Before the Test
No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the test if it involves drawing blood. Avoid taking phosphorus supplements or certain medications for 24 hours before the test if instructed.
How the Test Is Performed
A healthcare professional will draw blood from a vein in your arm using a small needle. The blood sample will be sent to a lab to measure phosphorus levels using a specialized test method.
Possible Results and Interpretation
Results are typically reported as a mass concentration (e.g., mg/dL or mmol/L). High or low phosphorus levels may indicate underlying health issues that need further evaluation.
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.
High phosphorus levels (hyperphosphatemia) can occur due to kidney problems, certain medications, or excessive intake of phosphorus supplements. Low phosphorus levels (hypophosphatemia) may result from malnutrition, chronic alcoholism, or conditions affecting bone metabolism. Both extremes can affect bone health, muscle function, and other metabolic processes.
Short name
Serum/Plasma Phosphorus
Frequently asked questions
What Causes High Phosphorus Levels?
What Causes Low Phosphorus Levels?
Can Diet Affect Phosphorus Levels?
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