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C-reactive protein (CRP) by immunoassay (quantitative)

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

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

Quick summary

["CRP helps doctors track inflammation, infections, or other health issues."]

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

Key facts at a glance

LOINC
33943-2
Short code
C pn+psitt DNA CSF Ql NAA+probe
Synonyms
C pn+psitt DNA CSF Ql NAA+probe
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
probe-amp-tar
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 conditions like arthritis, heart disease, or infections, or evaluate responses to treatments. It can also help identify risks for certain health problems before symptoms appear.

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 often indicate inflammation, but results alone don’t diagnose a specific condition. Your doctor will review your full medical history and other test results for context.

Common Causes of Elevated CRP

Elevated CRP can be caused by infections (like pneumonia or urinary tract infections), autoimmune diseases (like rheumatoid arthritis), heart disease, or other inflammatory conditions. Stress, smoking, or certain medications may also affect levels.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Elevated CRP levels may signal inflammation, but they don’t pinpoint the exact cause. Your doctor will use the results alongside other tests and symptoms to guide treatment or further investigation.

Short name

CRP (Serum)

Frequently asked questions

What if my CRP is high?
If your CRP is high, your doctor may recommend additional tests or treatments to address the underlying cause, such as antibiotics for infections or lifestyle changes to reduce inflammation.
Does diet affect CRP levels?
Yes, diet can influence CRP levels. Eating a balanced diet rich in fruits, vegetables, and omega-3 fatty acids may help lower inflammation, while processed foods and excessive sugar can raise them.
Can CRP levels be affected by medications?
Some medications, like steroids or nonsteroidal anti-inflammatory drugs (NSAIDs), can lower CRP levels. Always discuss any medications with your doctor before interpreting results.
  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