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C-reactive protein (CRP) concentration, serum/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 doctors assess inflammation, often used to monitor conditions like infections or autoimmune diseases."]

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

Key facts at a glance

LOINC
36917-3
Short code
Chr UpDi Bld/T
Synonyms
Chr UpDi Bld/T
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
molgen
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

Why This Test Matters

CRP is a marker for inflammation, which can occur due to infections, injuries, or certain medical conditions. High levels may signal an active inflammatory process that needs attention.

What to Expect Before the Test

No special preparation is needed for this blood test. 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.

Common Uses of CRP Testing

Doctors often use CRP to monitor chronic conditions like rheumatoid arthritis or heart disease. It may also be checked after surgery or trauma to track healing progress.

How CRP Levels Are Interpreted

While reference ranges vary by lab, CRP levels are generally categorized as low (normal), moderate, or high. High levels may prompt further evaluation for underlying causes.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CRP

Frequently asked questions

What causes CRP levels to rise?
CRP levels can increase due to infections (like pneumonia or urinary tract infections), injuries, surgeries, or certain medical conditions such as autoimmune diseases (e.g., lupus) or heart disease.
How soon after an event (like surgery) can CRP levels return to normal?
CRP levels typically peak within days after an event (like surgery or trauma) and gradually return to baseline over weeks to months, depending on the cause and individual health.
Can diet or lifestyle affect CRP levels?
Yes, diet, exercise, and weight management can influence inflammation. Reducing processed foods, increasing omega-3s (found in fish), and maintaining a healthy weight 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