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C-reactive protein (CRP) concentration, high-sensitivity

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

This test measures a protein in your blood that rises when your body is fighting inflammation, often used to check for low-grade inflammation or risk of heart disease.

Quick summary

["A simple blood test to assess subtle inflammation or cardiovascular risk."]

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

Key facts at a glance

LOINC
24725-4
Short code
CT Head
Synonyms
CT Head
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 This Test Done?

Doctors may order a high-sensitivity CRP test to monitor chronic inflammation, evaluate risk for heart attacks or strokes, or check for conditions like autoimmune diseases. It’s sometimes used alongside other tests to guide treatment decisions.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your arm, and a blood sample will be drawn. It usually takes a few minutes, and you can resume normal activities afterward.

What the Results Mean

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

Common Causes of Abnormal Results

Elevated CRP can be caused by infections, injuries, autoimmune diseases, or certain medications. Low levels may suggest reduced inflammation but could also be normal for some individuals.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

hs-CRP

Frequently asked questions

What does a high CRP level mean?
A high CRP level suggests your body is actively responding to inflammation, which could be due to infection, injury, or an underlying condition like arthritis or heart disease. Your doctor will discuss further steps based on your results and symptoms.
Does fasting affect CRP levels?
Fasting does not significantly impact CRP levels, as it measures a protein produced by the liver in response to inflammation, not food intake. However, always follow your doctor’s instructions for test preparation.
How often should I get this test?
Your doctor will determine the frequency based on your health needs. Some people get it yearly for cardiovascular risk assessment, while others may need it more often if they have chronic conditions like heart disease or arthritis.
  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