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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 after surgery."]

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

Key facts at a glance

LOINC
3227-6
Short code
Fact XI PPP Chro-aCnc
Synonyms
Fact XI PPP Chro-aCnc
Category
chemistry
Sample
plasma
Container
Lavender-top (EDTA) or Green-top (Heparin)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
chromo
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 in Your Health

CRP is a marker that rises when your body is fighting inflammation. High levels may signal infections, injuries, or conditions like arthritis or heart disease. Your doctor may order this test to check for these issues or to monitor treatment progress.

When This Test Is Done

Doctors often request CRP testing during routine check-ups, after an injury or surgery, or when diagnosing conditions like infections, autoimmune diseases, or heart problems. It can also be used to track how well certain treatments are working.

What to Expect Before the Test

You’ll likely have a small needle inserted into your arm to draw blood. No special preparation is needed, but avoid heavy exercise or eating a large meal before the test. If you’re on blood thinners, let your doctor know.

What the Results Mean

Results are usually reported in milligrams per liter (mg/L). Very low levels may indicate no active inflammation, while very high levels could suggest serious conditions. Your doctor will interpret results in the context of your overall health and symptoms.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CRP (Serum/Plasma)

Frequently asked questions

How often should I get this test?
Your doctor will determine how often you need CRP testing based on your medical history, symptoms, and treatment plan. Some people may need it monthly, while others may only need it once or twice a year.
Can diet or exercise affect CRP levels?
Yes, lifestyle factors like diet, exercise, and stress can influence CRP levels. Eating a heart-healthy diet, staying active, and managing stress may help lower CRP levels over time.
What if my CRP is elevated?
If your CRP is elevated, your doctor may investigate possible causes like infections, autoimmune diseases, or heart issues. They may recommend further testing or changes to your treatment plan to address the underlying problem.
  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