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

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

This test measures the level of C-reactive protein, a protein produced by your liver in response to inflammation or infection in your body.

Quick summary

["CRP helps doctors assess inflammation and track conditions like infections, autoimmune diseases, or heart disease."]

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

Key facts at a glance

LOINC
5657-2
Short code
Gold CSF-mCnc
Synonyms
Gold CSF-mCnc
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your doctor may order a CRP test to check for signs of inflammation, monitor chronic conditions, or evaluate symptoms like fever, joint pain, or swelling. It’s often used alongside other tests to diagnose or guide treatment for conditions like infections, arthritis, or heart disease.

What to Expect Before the Test

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

What the Results Mean

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

Common Conditions Monitored

CRP is used to monitor conditions like rheumatoid arthritis, lupus, infections (e.g., pneumonia), heart disease, or after surgeries/injuries to check for complications.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: CRP is a nonspecific marker of inflammation. While it doesn’t pinpoint the cause of inflammation, elevated levels often signal underlying issues that may require further testing or medical attention. Your doctor will use these results to guide treatment decisions or adjust medications if needed.

Short name

CRP (Plasma)

Frequently asked questions

What causes CRP levels to be higher than usual?
CRP levels can rise due to infections (like colds or flu), injuries, surgeries, autoimmune diseases (such as rheumatoid arthritis), or certain medications. Stress, obesity, or smoking may also temporarily increase CRP.
How long does it take to get results?
Results are typically available within 24 to 48 hours, depending on your lab’s processing time. Your doctor will contact you once they have the results.
Can diet or exercise affect CRP levels?
Yes, lifestyle factors like diet (e.g., Mediterranean diet), exercise, and weight management may influence CRP levels. Avoiding smoking and managing stress can also help keep inflammation lower.
  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