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

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

Key facts at a glance

LOINC
16763-5
Short code
DDE Ur-mCnc
Synonyms
DDE 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 CRP Matters in Your Health

CRP is a marker that signals your body’s immune system is active. High levels may indicate inflammation, which can be caused by infections, injuries, or certain diseases. It’s not specific to one condition but helps guide treatment decisions.

When This Test Is Ordered

Your doctor may order CRP testing to check for signs of inflammation before or after surgery, to monitor chronic conditions like arthritis or heart disease, or to evaluate symptoms like fever, joint pain, or unexplained fatigue.

What to Expect During the Test

A blood sample is taken from a vein, usually in your arm. You may feel a small pinch, but it’s quick and doesn’t require special preparation. The test is done in a lab and results are typically ready within a few days.

Common Conditions Monitored

CRP is often used alongside other tests to diagnose or manage conditions like infections (e.g., pneumonia), autoimmune diseases (e.g., rheumatoid arthritis), or to check for signs of inflammation after trauma or surgery.

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 in your body. While it doesn’t identify the exact cause, it can help your doctor determine if you need further testing or treatment for conditions like infections, autoimmune diseases, or other inflammatory processes.
What does a low CRP level mean?
A low CRP level usually means there is little to no inflammation detected in your blood. However, it doesn’t rule out all possible causes of symptoms—other tests may still be needed to diagnose your condition.
How often should I get this test?
Your doctor will determine how often you need CRP testing based on your health condition, symptoms, and treatment plan. Regular monitoring may be recommended for chronic diseases like heart disease or arthritis.
  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