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C-reactive protein (CRP) concentration in 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 identify and monitor inflammation, often used to check for infections or other inflammatory conditions."]

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

Key facts at a glance

LOINC
37435-5
Short code
MR TMJ Cine
Synonyms
MR TMJ Cine
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
mr
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 CRP Matters in Your Health

CRP is a marker for inflammation, which can occur due to infections, injuries, autoimmune diseases, or other conditions. High CRP levels may signal an active inflammatory process that your body is responding to.

When This Test Is Ordered

Your healthcare provider may order CRP testing to evaluate symptoms like fever, joint pain, or unexplained fatigue. It’s also used before surgeries, to monitor chronic conditions like rheumatoid arthritis, or to assess response to treatment.

What to Expect Before the Test

No special preparation is needed for this test. You may have blood drawn from a vein in your arm, similar to other blood tests. If you’re on blood thinners, let your provider know before the test.

What the Results Mean

Results are typically reported in milligrams per liter (mg/L). While reference ranges vary by lab, very high levels may indicate severe inflammation or infection, while very low levels might suggest reduced immune response or certain medical conditions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

CRP is a key tool for diagnosing and managing inflammatory diseases. Elevated CRP can prompt further testing for infections, autoimmune disorders, or other underlying causes. It’s also useful for tracking how well treatments are working over time.

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 chronic conditions such as rheumatoid arthritis. Stress, smoking, or obesity may also influence CRP levels.
How often should I get this test?
Your provider will determine how often you need CRP testing based on your health status. Some people get it once a year for general health checks, while others may need it more frequently if they have ongoing inflammatory conditions.
Can diet or lifestyle changes affect CRP levels?
Yes, lifestyle factors like diet, exercise, and smoking can impact CRP levels. Eating a heart-healthy diet, managing weight, and quitting smoking may help lower CRP and reduce inflammation.
  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