Phosphorus (Serum or Plasma) Concentration
This test measures the amount of phosphorus, an essential mineral, in your blood. Phosphorus works with calcium to maintain strong bones and healthy teeth, and it also plays a role in energy production and cell function.
["Your blood phosphorus levels help doctors assess bone health, kidney function, and overall mineral balance."]
Key facts at a glance
- LOINC
- 108011-8
- Short code
- Phosphate Msmt Ur
- Synonyms
- Phosphate Msmt Ur
- 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 doctor may recommend this test if you have symptoms like muscle weakness, bone pain, or frequent fractures. It’s also checked when monitoring conditions such as kidney disease, metabolic disorders, or after treatments like chemotherapy or certain medications that affect mineral balance.
What to Expect Before the Test
No special preparation is needed for this test. You’ll have a small needle inserted into your arm to draw blood. If you’re on dialysis or have a central venous catheter, your blood may be drawn from that site instead.
What to Expect During the Test
The blood draw usually takes just a few minutes. You might feel a slight pinch, but most people describe it as minimal discomfort. Afterward, you can resume normal activities.
Possible Results and Next Steps
Results are typically reviewed by your healthcare provider. Low phosphorus levels (hypophosphatemia) may require dietary adjustments or supplements, while high levels (hyperphosphatemia) could indicate kidney issues or other health concerns 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.
Clinical Significance
Short name
Serum Phosphorus
Frequently asked questions
What could my phosphorus levels mean?
How often should I get this test?
Can I eat or drink before the 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