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C-reactive protein (CRP) concentration, serum/plasma

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

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

Quick summary

["CRP helps doctors track inflammation, infection, or other health issues."]

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

Key facts at a glance

LOINC
82713-9
Short code
CTA UE ves-L
Synonyms
CTA UE ves-L
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-angio
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 It’s Done

Your doctor may order a CRP test to check for signs of inflammation, monitor conditions like arthritis, heart disease, or infections, or evaluate how your body is responding to treatment for a medical condition.

What to Expect

A small blood sample is taken from a vein, usually in your arm. The sample is sent to a lab where it is analyzed to measure CRP levels. Results are typically available within a few days.

What the Results Mean

CRP levels can vary widely depending on health status, age, and other factors. Higher than usual levels may indicate inflammation, infection, or other health concerns. Your doctor will interpret the results in the context of your overall health and medical history.

Common Conditions Monitored

Elevated CRP levels are often used to monitor conditions such as rheumatoid arthritis, heart disease, infections (like pneumonia or sepsis), and other inflammatory diseases. It can also be checked after surgery or injury to assess healing progress.

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 higher than usual?
CRP levels can rise due to infections (like colds, flu, or urinary tract infections), injuries, surgeries, or certain medical conditions such as arthritis, heart disease, or autoimmune disorders. Stress, smoking, and certain medications can also influence CRP levels.
How long do CRP levels stay elevated?
The duration CRP levels remain elevated depends on the cause. For infections or short-term inflammation, levels may return to normal within days to weeks. For chronic conditions like arthritis, CRP levels might stay elevated over months or longer.
Can CRP levels be affected by diet or lifestyle?
Yes, lifestyle factors like diet, exercise, and smoking can influence CRP levels. A healthy diet rich in fruits, vegetables, and omega-3 fatty acids, along with regular physical activity, may help reduce inflammation. Avoiding smoking and managing stress can also support lower CRP levels.
  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