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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 doctors assess inflammation, often used to monitor conditions like infections, autoimmune diseases, or heart disease risk."]

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

Key facts at a glance

LOINC
22206-7
Short code
C immitis Ab Ser-aCnc
Synonyms
C immitis Ab Ser-aCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 Is This Test Done?

Your healthcare provider may order this test to check for signs of inflammation, monitor chronic conditions, or evaluate risk for conditions like heart disease or certain infections. It can also help track how well treatments are working for conditions such as arthritis or other inflammatory diseases.

What to Expect During the Test

A small amount of blood is drawn from a vein in your arm. You may feel a slight pinch, but it usually doesn’t cause much discomfort. The blood is then sent to a lab for testing.

Common Conditions Monitored

High CRP levels may indicate an active infection, an autoimmune condition, or inflammation from other causes. Low levels might suggest your body is not responding to inflammation, though this isn’t always the case.

How Results Are Interpreted

Results are typically reported in milligrams per liter (mg/L). While reference ranges can vary by lab, very high levels often signal urgent conditions requiring further investigation.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CRP (Serum/Plasma)

Frequently asked questions

What causes CRP levels to be high?
High CRP levels can be caused by infections (like pneumonia or urinary tract infections), injuries, surgeries, or inflammatory diseases (like rheumatoid arthritis). Stress, smoking, or certain medications may also influence results.
Can diet or lifestyle affect CRP levels?
Yes, diet and lifestyle choices can impact CRP levels. Eating a heart-healthy diet, managing weight, quitting smoking, and reducing stress may help lower CRP levels over time.
How often should I get this test?
Your doctor will determine how often you need this test based on your health condition and symptoms. Regular monitoring may be recommended if you have chronic inflammation or a history of heart disease or infections.
  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