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C-reactive protein, mass 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
11133-6
Short code
FCA Ur-mCnc
Synonyms
FCA Ur-mCnc
Category
chemistry
Sample
urine
Container
Sterile urine container
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
10 mL
Stability
Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
0
Lipemia max
0
Icterus max
0
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 like rheumatoid arthritis or lupus, or evaluate responses to treatments. It can also help diagnose infections, such as pneumonia or sepsis, or assess risk for 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 concerned about needles, let your provider know. Avoid heavy exercise or strenuous activity 24 hours before the test.

What Happens During the Test?

Blood is collected from a vein in your arm using a needle. The sample is then sent to a lab for analysis. The process usually takes a few minutes.

What Are the Results Measured Against?

Results are compared to general reference ranges for healthy adults, though individual ranges may vary based on medical conditions or age. Higher than usual levels may indicate inflammation or infection.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CRP (Serum/Plasma)

Frequently asked questions

What Does a High CRP Level Mean?
A high CRP level suggests inflammation is present. This could be due to infections, injuries, or conditions like rheumatoid arthritis. Your doctor will consider your symptoms and other test results to determine the cause.
What Does a Low CRP Level Mean?
A low CRP level typically means there’s little to no inflammation detected in your blood. However, it doesn’t rule out all causes of inflammation, so your doctor may still recommend further evaluation if needed.
Can Diet or Exercise Affect CRP Levels?
Yes, lifestyle factors like diet, exercise, and smoking can influence CRP levels. Eating a heart-healthy diet, staying active, and avoiding smoking may help lower CRP and reduce inflammation 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