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C-reactive protein (serum/plasma) concentration

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

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

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
14465-9
Short code
C trach Urth Ql Cult
Synonyms
C trach Urth Ql Cult
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
organism-specific-culture
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 a CRP test to check for signs of inflammation, monitor conditions like infections, autoimmune diseases, or heart disease, or evaluate responses to treatments. It can also help identify risks for conditions such as heart attacks or certain cancers.

What Does a High or Low CRP Level Mean?

A higher-than-normal CRP level often indicates inflammation, which can be linked to infections, injuries, or diseases like rheumatoid arthritis or lupus. A very high level may suggest severe infection or other serious conditions. A low level usually means minimal inflammation, but it doesn’t rule out all possible causes.

How Is the CRP Test Performed?

A blood sample is taken from a vein in your arm. The blood is sent to a lab, where it is analyzed using an immunoassay method to measure CRP concentration.

What Are Common Causes of Abnormal CRP Levels?

Infections (like pneumonia or urinary tract infections), injuries, surgeries, or certain medications can raise CRP levels. Conversely, conditions like chronic heart disease, certain cancers, or long-term inflammation may also affect CRP levels.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

CRP levels can indicate whether inflammation is active, but they don’t always pinpoint the exact cause. Doctors use CRP alongside other tests and symptoms to guide diagnosis and treatment plans.

Short name

CRP

Frequently asked questions

What if I Have Questions About My CRP Test Results?
If your CRP test results are abnormal, discuss them with your healthcare provider. They may ask about symptoms, medical history, or other tests to understand what’s happening in your body.
How Often Should I Get a CRP Test?
The frequency depends on your health condition and treatment plan. Your doctor will determine how often you need this test based on your needs and medical situation.
Can I Do Anything to Lower My CRP Levels?
Lifestyle changes like eating a heart-healthy diet, staying physically active, managing stress, and avoiding smoking can help reduce inflammation and may lower CRP levels over time. Always follow your doctor’s advice for personalized guidance.
  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