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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 the body.

Quick summary

["CRP helps track inflammation, often used to monitor conditions like infections or autoimmune diseases."]

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

Key facts at a glance

LOINC
93773-0
Short code
11DC Sal-sCnc
Synonyms
11DC Sal-sCnc
Category
hormone
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 CRP Matters

CRP is a marker for inflammation, meaning it rises when your body is fighting off infections, healing from injury, or dealing with conditions like arthritis or heart disease. It’s not specific to one cause but helps doctors assess overall inflammation levels.

When You Might Get This Test

Your doctor may order CRP testing if you have symptoms of inflammation, such as fever, joint pain, or swelling. It’s also used before and after treatments like chemotherapy or surgeries to monitor how your body responds.

How the Test Works

A small blood sample is taken from your arm, usually in a clinic or lab. The blood is processed to separate serum or plasma, where CRP levels are measured using an immunoassay or similar method to detect its presence.

What the Results Mean

Higher CRP levels often indicate active inflammation, while lower levels suggest reduced inflammation. However, results alone don’t diagnose a specific condition—your doctor will consider them alongside other tests and symptoms.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CRP

Frequently asked questions

What does a high CRP level mean?
A high CRP level suggests inflammation is present in your body, which could be due to infections, injuries, autoimmune diseases, or other conditions. Your doctor will discuss the results with you to determine the next steps.
Can CRP levels change with diet or exercise?
While diet and exercise can influence inflammation in general, CRP levels are primarily measured as a snapshot of current inflammation. Changes in lifestyle may affect future CRP levels, but results from a single test don’t reflect long-term trends.
Is CRP the same as a white blood cell count?
No, CRP is a protein marker for inflammation, while a white blood cell count measures the number of immune cells in your blood. Both tests are useful but provide different information about your health.
  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