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C-reactive protein (CRP) concentration

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

This test measures the level of C-reactive protein, a protein produced by your 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 heart disease."]

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

Key facts at a glance

LOINC
35971-1
Short code
CT LE
Synonyms
CT LE
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
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 is CRP tested?

Your doctor may order CRP testing to check for signs of inflammation, monitor chronic conditions, or evaluate symptoms like fever, joint pain, or swelling. It can also help guide treatment decisions for conditions like arthritis, heart disease, or infections.

What does CRP measure?

CRP measures the amount of a protein in your blood that rises when your body is inflamed. This protein is a marker of how active inflammation is in your system.

How is CRP tested?

A blood sample is taken from a vein in your arm. The sample is sent to a lab where it is analyzed using a sensitive immunoassay method to detect CRP levels.

What might affect CRP levels?

Several factors can influence CRP levels, including infections, injuries, certain medications, smoking, stress, and underlying health conditions like heart disease or autoimmune disorders.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CRP

Frequently asked questions

What are normal CRP levels?
Normal CRP levels vary and depend on the context of your health. Low levels may indicate no significant inflammation, while higher levels can signal inflammation or infection that needs further evaluation.
How soon will I get my CRP test results?
Results are typically available within a few days, depending on your lab’s processing time. Your healthcare provider will discuss the results with you during your follow-up visit.
Can I eat or drink before my CRP test?
You can usually eat and drink normally before your CRP test, as it does not require fasting. However, always follow your healthcare provider’s specific instructions for your appointment.
  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