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C-reactive protein (CRP) by nephelometry (serum/plasma)

Published: August 9, 2026Updated: August 16, 2026

This test measures a protein produced by the liver in response to inflammation, helping detect or monitor conditions like infections, autoimmune diseases, or injury.

Quick summary

["Helps track inflammation levels in your body."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
41866-5
Short code
Deprecated vWF Ag Act/Nor PPP EIA
Synonyms
Deprecated vWF Ag Act/Nor PPP EIA
Category
chemistry
Sample
plasma
Container
Lavender-top (EDTA) or Green-top (Heparin)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
eia
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 Is This Test Done?

Your doctor may order this test to check for signs of inflammation, evaluate conditions like infections, arthritis, or heart disease, or monitor treatment progress for certain illnesses.

What to Expect Before the Test

No special preparation is needed. You may have a small needle inserted into your arm or vein to draw blood. If you’re on blood thinners, let your doctor know before the test.

What the Results Mean

Higher-than-normal CRP levels may indicate inflammation, but they can also be influenced by factors like stress, recent illness, or medications. Your doctor will interpret results in the context of your health history.

Common Conditions Monitored

This test is often used to monitor conditions like rheumatoid arthritis, lupus, heart disease, or infections, though it’s not definitive for diagnosis alone.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Elevated CRP levels can signal inflammation but aren’t specific to any single condition. They’re most useful when tracked over time or alongside other tests for a clearer picture of your health.

Short name

CRP (High-Sensitivity)

Frequently asked questions

What causes CRP levels to rise?
CRP levels can increase due to infections (like pneumonia or urinary tract infections), injuries, surgeries, autoimmune diseases (like rheumatoid arthritis), or other inflammatory processes. Stress, smoking, or certain medications can also affect results.
How often should I get this test?
Your doctor will determine how often you need this test based on your medical needs, such as whether you have a chronic condition requiring monitoring or if you’re recovering from an illness.
Can diet or lifestyle affect CRP levels?
Yes, diet high in processed foods, sugar, or unhealthy fats may contribute to inflammation, potentially raising CRP levels. Regular exercise, a balanced diet, and reducing stress can help lower inflammation naturally.
  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 16, 2026. · Read our editorial policy