Phosphorus (Serum) Mass Concentration
This test measures the amount of phosphorus, a mineral essential for healthy bones and cells, in your blood serum. Phosphorus levels can help assess conditions affecting bone metabolism or kidney function.
["Phosphorus levels can indicate kidney function or metabolic bone disorders."]
Key facts at a glance
- LOINC
- 87456-0
- Short code
- Phosphate Spec-mCnc
- Synonyms
- Phosphate Spec-mCnc
- Category
- electrolyte
- Sample
- serum
- Container
- Red-top tube (SST)
- 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
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
Why This Test Might Be Ordered
Your healthcare provider may recommend this test if you have symptoms like muscle weakness, bone pain, or signs of kidney disease. It may also be checked during evaluations for conditions like hypophosphatemia (low phosphorus) or hyperphosphatemia (high phosphorus), or to monitor treatment for metabolic bone diseases.
What to Expect Before the Test
No special preparation is typically needed. You may fast before the test if instructed by your provider, but always follow their guidance. Bring any medications you’re currently taking.
What the Test Results Mean
Results help determine if your phosphorus levels are within normal ranges. Abnormal levels may signal underlying health issues that need further evaluation by your doctor.
Common Conditions Affecting Phosphorus Levels
Low phosphorus levels (hypophosphatemia) can occur due to conditions like malnutrition, kidney disease, or excessive use of certain medications. High phosphorus levels (hyperphosphatemia) may result from kidney problems, certain cancers, or overuse of phosphate supplements.
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.
Phosphorus is vital for bone health, energy production, and cell function. Abnormal levels can affect muscle function, bone density, and overall metabolism. Your provider will interpret results in the context of your symptoms and medical history to guide next steps.
Short name
Serum Phosphorus Level
Frequently asked questions
What causes low phosphorus levels?
What are the symptoms of abnormal phosphorus levels?
How is phosphorus tested?
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