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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
104550-9
Short code
mDC # Bld FC
Synonyms
mDC # Bld FC
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
flow-cytometry
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

Why Is CRP Tested?

Doctors 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 like heart disease or rheumatoid arthritis.

What Does CRP Tell You About Your Health?

Higher CRP levels often indicate inflammation, which can be linked to infections, injuries, or chronic health issues. However, CRP alone doesn’t diagnose a specific condition—it’s used alongside other tests and symptoms.

How Is the CRP Test Performed?

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

What Are Common CRP Reference Ranges?

Reference ranges vary by lab, but typically, normal CRP levels are low (often below 1 mg/L). Elevated levels may suggest inflammation, but interpretation depends on clinical context.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CRP

Frequently asked questions

What causes CRP levels to be high?
High CRP levels can result from infections (like pneumonia or urinary tract infections), injuries, surgeries, autoimmune diseases (like lupus or rheumatoid arthritis), or other inflammatory conditions. Stress, obesity, or certain medications may also affect CRP levels.
How long does it take to get CRP test results?
Results are usually available within 1 to 3 business days, depending on your lab’s processing time. Your doctor will discuss the results with you during your follow-up visit.
Can CRP levels change without a serious illness?
Yes, CRP can rise due to minor infections, mild inflammation, or even routine activities like exercise. However, persistent or significantly elevated CRP levels warrant further investigation by a healthcare provider.
  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