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C-reactive protein (high-sensitivity, serum/plasma)

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

This test measures a protein called C-reactive protein (CRP) in your blood. CRP is produced by your liver in response to inflammation, helping your body fight infections or injury.

Quick summary

["CRP helps track inflammation, which can signal underlying health issues."]

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

Key facts at a glance

LOINC
41806-1
Short code
CT Abd
Synonyms
CT Abd
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

What Is CRP Used For?

CRP is often used to monitor conditions like infections, autoimmune diseases, or after surgery to check for inflammation. High levels may suggest an infection, injury, or conditions like rheumatoid arthritis or heart disease.

How Is CRP Tested?

Your blood sample is taken from a vein, usually in your arm. The test measures CRP levels using a sensitive method to detect even small amounts of inflammation in your bloodstream.

Why Might You Need This Test?

Your doctor may order this test if you have symptoms of inflammation, such as fever, pain, or swelling, or if you have a known condition that affects inflammation levels.

What Do Results Mean?

Results are not always interpreted alone—they’re often checked alongside other symptoms and tests. Very high levels may indicate severe inflammation, while very low levels might mean inflammation is under control.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

hs-CRP

Frequently asked questions

What causes CRP levels to change?
CRP rises when your body is fighting infections, healing from injury, or dealing with conditions like arthritis or heart disease. Stress, certain medications, or recent procedures can also temporarily affect levels.
How soon after a trigger do CRP levels change?
CRP levels can start rising within hours of an infection or injury and may peak in a few days. They often return to normal within weeks, depending on the cause.
Can CRP levels be affected by diet or supplements?
Dietary changes or supplements like omega-3s or turmeric may influence inflammation, but CRP levels are primarily driven by your body’s response to illness or injury. Always discuss supplements with your doctor.
  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