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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 the liver in response to inflammation in your body.

Quick summary

["CRP helps identify inflammation, often used to monitor conditions like infections, autoimmune diseases, or post-surgery recovery."]

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

Key facts at a glance

LOINC
81734-6
Short code
Deprecated ENA RNP Ab CSF Ql IB
Synonyms
Deprecated ENA RNP Ab CSF Ql IB
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ib
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 healthcare provider may order this test to check for signs of inflammation, monitor chronic conditions, or evaluate responses to treatments. CRP levels can also help assess risk for heart disease or other inflammatory conditions.

What to Expect Before the Test

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

What the Results Mean

Results are not provided as a single numeric range since reference intervals vary by lab and condition. Elevated CRP levels often indicate inflammation, while lower levels suggest minimal or no inflammation. Your provider will interpret results in the context of your health history.

Common Conditions Monitored

This test is commonly used to monitor conditions like rheumatoid arthritis, lupus, infections (e.g., pneumonia), heart disease, or after surgery to track healing.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: CRP as an Inflammatory Marker

Short name

CRP Plasma

Frequently asked questions

What Does a High CRP Level Indicate?
A high CRP level often signals inflammation in your body, which can be caused by infections, autoimmune diseases, or other health issues. However, CRP alone isn’t diagnostic—your provider will consider other factors, like symptoms and test results.
How Often Should I Get This Test?
Your provider will determine how often you need this test based on your medical needs. Some people get it yearly, while others may need it more frequently if they have ongoing health concerns.
Can Diet or Exercise Affect CRP Levels?
Yes, lifestyle factors like diet, exercise, and stress can influence CRP levels. Eating a heart-healthy diet, staying active, and managing stress may help lower CRP levels over time.
  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