CRP blood test
C-reactive protein
In short
A typical adult CRP result is under 5 mg/L. A mild rise is common with a cold, a small injury, extra weight or smoking. Higher levels usually point to an infection or a flare of an inflammatory condition. Always read your result against the range printed on your own report.
A protein the liver makes when there is inflammation.
The liver releases CRP into the blood when the body is fighting an infection or inflammation. It rises within hours and falls quickly once the cause settles. It shows that inflammation is present, but not where it is or what is causing it.
Is my CRP high or low?
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Typical range
| For | Range | Unit |
|---|---|---|
| Adults | under 5 | mg/L |
| Adults | under 0.5 | mg/dL |
Typical ranges for adults. Labs differ a little, so the range printed next to your result is the one to go by.
If your CRP is high
A mild rise is common with a cold, a small injury, extra weight or smoking. Higher levels usually point to an infection or a flare of an inflammatory condition.
Common reasons
- A cold, flu or other recent infection
- A recent injury or surgery
- Extra body weight or smoking
- Pregnancy, birth control pills or hormone therapy
- A flare of arthritis, bowel inflammation or another inflammatory condition
- Less often: a serious bacterial infection, or a tumor
What can throw it off
A cold or a minor injury in the days before the test can raise CRP for a while.
Questions to take to your appointment
- 1Could a recent cold or injury explain this?
- 2Should it be repeated once I feel well?
- 3Do my white cell count and other tests point the same way?
Read together with
Doctors rarely read CRP alone. These usually sit next to it.
Quick answers
What is the CRP blood test?
CRP (C-reactive protein): A protein the liver makes when there is inflammation. The liver releases CRP into the blood when the body is fighting an infection or inflammation. It rises within hours and falls quickly once the cause settles. It shows that inflammation is present, but not where it is or what is causing it.
What is a normal CRP level?
For most adults, CRP is typically under 5 mg/L. Some countries print it in mg/dL, so check the unit first. Labs differ a little, so the range printed next to your result is the one to go by.
What does a high CRP mean?
A mild rise is common with a cold, a small injury, extra weight or smoking. Higher levels usually point to an infection or a flare of an inflammatory condition. Common reasons include a cold, flu or other recent infection; a recent injury or surgery; extra body weight or smoking; and pregnancy, birth control pills or hormone therapy. A doctor reads it together with your other results and how you feel.
What can affect my CRP result?
A cold or a minor injury in the days before the test can raise CRP for a while.
What should I ask my doctor about my CRP?
Questions worth taking to the appointment: Could a recent cold or injury explain this? Should it be repeated once I feel well? Do my white cell count and other tests point the same way?
What this page can’t do
It reads each number on its own.
Doctors read results together — ALT with AST, ferritin with hemoglobin, TSH with free T4. A pattern says more than any single flag.
It doesn't know you.
Your age, your medicines, how you feel and your last result all change what a number means.
It doesn't remember.
Close this page and your results are gone. That's on purpose: nothing was ever sent to us.
We also make Vita: Health Coach, an app for those parts. It reads your whole report with your medicines and history in mind, answers follow-up questions in plain words, and keeps your reports in one place — for you and for the people you look after.
Vita: Health Coach on the App StoreSources
- Mayo Clinic Laboratories — C-Reactive Protein (CRP), Serum
- ABIM — Laboratory Test Reference Ranges (January 2026)
Stuck on a word? See the medical words. How we choose our sources. More about Vita Health Coach.