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C-Reactive Protein (CRP) 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 identify and monitor inflammation, often used to check for infections or other inflammatory conditions."]

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

Key facts at a glance

LOINC
51452-1
Short code
C immitis Ab Titr Fld
Synonyms
C immitis Ab Titr Fld
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
86430
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 This Test Is Done

Your doctor may order this test to evaluate signs of inflammation, detect infections (such as pneumonia or urinary tract infections), assess risk for heart disease, or monitor conditions like rheumatoid arthritis or lupus. It can also help track how well treatment is working for certain inflammatory diseases.

What to Expect Before the Test

No special preparation is needed. You may have a small needle inserted into a vein in your arm to draw blood. If you’re concerned about needles, let your healthcare provider know. Avoid heavy exercise or strenuous activity 24 hours before the test.

What the Results Mean

Results are typically reported in milligrams per liter (mg/L). Higher levels may indicate inflammation, infections, or other health issues. Your doctor will interpret the results in the context of your overall health and symptoms.

Common Conditions Monitored

CRP is used to monitor conditions like autoimmune diseases (e.g., rheumatoid arthritis), infections, heart disease risk, and post-surgery or post-injury recovery. It’s also part of routine check-ups for people at higher risk for heart disease.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

CRP

Frequently asked questions

What does a high CRP level mean?
A high CRP level often signals inflammation in the body, which can be caused by infections, autoimmune diseases, or other inflammatory conditions. Your doctor may use these results to guide treatment decisions or adjust medications.
Can CRP levels be affected by diet or lifestyle?
Yes, certain foods, smoking, exercise, and stress can influence CRP levels. For example, a healthy diet and regular physical activity may help lower CRP. However, CRP is primarily a marker of inflammation, not a direct measure of diet or lifestyle alone.
How often should I get this test?
Your doctor will determine the frequency based on your health status, symptoms, and treatment plan. Some people may need CRP tests every few months or annually, while others may only need it occasionally.
  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