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Phosphorus (Phosphate) Level in Serum or Plasma

Published: August 9, 2026Updated: August 17, 2026

This test measures the amount of phosphate, a mineral essential for healthy bones, cells, and energy production, in your blood.

Quick summary

["Phosphate levels help assess bone health and metabolic function."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
48046-7
Short code
Phosphate CtO Stl-mCnt
Synonyms
Phosphate CtO Stl-mCnt
Category
electrolyte
Sample
stool
Container
Clean 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
5 g
Stability
Refrigerated: 24h, Frozen: 7d
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your doctor may order this test to check for conditions affecting phosphate balance, such as kidney disease, metabolic disorders, or bone-related issues. It can also help monitor treatment for conditions like hyperparathyroidism or hypoparathyroidism.

What Does the Test Involve?

A blood sample is taken from a vein, usually in your arm. The sample is sent to a lab where phosphate levels are measured using an enzymatic method.

What Are Normal Results?

Normal results vary by lab and individual, but they generally fall within a specific range. Your doctor will compare your results to your personal baseline or lab-specific reference values.

What Might Abnormal Results Mean?

Low phosphate levels may indicate conditions like malnutrition, kidney disease, or excessive loss of phosphate through urine or stool. High levels can suggest kidney problems, tumors, or certain metabolic disorders.

Reference range

Adult: 2.5-4.5 mg/dLN/A

Specimen: stool

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.

◆Associated findings1

Short name

Phosphate

Frequently asked questions

What causes phosphate levels to change in my blood?
Phosphate levels can be influenced by diet (especially intake of foods rich in phosphate), kidney function, certain medications, and underlying health conditions like diabetes or thyroid disorders.
How often should I get this test?
Your doctor will determine the frequency based on your health status, medical history, and any ongoing treatments. Regular testing may be recommended if you have a condition affecting phosphate balance.
Can I prepare for this test in any special way?
No special preparation is usually needed. However, avoid eating or drinking anything (except water) for a few hours before the test if instructed by your healthcare provider.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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