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C-reactive protein (CRP) concentration

Published: August 9, 2026Updated: August 16, 2026

This test measures the level of C-reactive protein in your blood. CRP is a protein produced by your liver in response to inflammation or infection.

Quick summary

["CRP helps doctors assess inflammation in your body."]

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

Key facts at a glance

LOINC
35945-5
Short code
CT TA + AA
Synonyms
CT TA + AA
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ct
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 Might You Need This Test?

Your healthcare provider may order a CRP test to check for signs of inflammation, infections, autoimmune conditions, or other health issues. It can also be used to monitor conditions like heart disease, arthritis, or after surgery to see how your body is healing.

What Does a High or Low CRP Level Mean?

A higher than normal CRP level often indicates inflammation, infection, or an autoimmune condition. A low level may suggest no active inflammation, but it doesn’t rule out other health concerns. Your results will be interpreted by your doctor based on your overall health and symptoms.

How Is the Test Done?

A blood sample is taken from a vein, usually in your arm. The sample is sent to a lab for testing. The process is quick and typically doesn’t cause discomfort beyond a minor pinch.

What Can Affect Your CRP Levels?

Several factors can influence CRP levels, including recent infections, injuries, stress, certain medications, smoking, and underlying health conditions like heart disease or diabetes. Your doctor will consider these factors when reviewing your results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CRP (Serum)

Frequently asked questions

What does a CRP test tell me about my health?
A CRP test helps identify inflammation in your body but doesn’t diagnose a specific condition. It’s often used alongside other tests and symptoms to guide further evaluation. Your doctor will explain what your results mean in the context of your health history and other tests.
How often should I get a CRP test?
The frequency of CRP testing depends on your medical needs. Your doctor may recommend it periodically if you have conditions like heart disease, arthritis, or if you’re at higher risk for inflammation-related problems. Follow your healthcare provider’s advice.
Can lifestyle changes affect CRP levels?
Yes, lifestyle factors such as diet, exercise, smoking, and stress can influence CRP levels. Reducing inflammation through healthy habits—like eating a balanced diet, staying active, and avoiding smoking—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