Your CRP level is one of the most commonly measured blood values. CRP (C-reactive protein) is a protein your liver produces in response to inflammation. An elevated CRP signals an inflammatory response somewhere in your body.
What is CRP?
CRP is an acute-phase protein produced rapidly during infection, inflammation or tissue damage. It is a non-specific marker: it tells you inflammation exists, but not where or why. This broad sensitivity makes it valuable as a screening value.
Normal values
Below 5 mg/L: normal. 5-10: mildly elevated. 10-50: moderately elevated (active inflammation). Above 50: significantly elevated (medical assessment needed). Above 200: severe infection possible.
What can elevated CRP mean?
Acute causes include infections, injuries and acute inflammation. Chronic causes include autoimmune diseases, obesity, smoking and cardiovascular disease.
hs-CRP for cardiovascular risk
High-sensitivity CRP measures the same marker with greater precision in the low range. Below 1 mg/L: low cardiovascular risk. 1-3: moderate. Above 3: elevated risk.
Frequently asked questions
Do I need to fast for a CRP test?
No, fasting is not required.
How quickly does CRP drop after infection?
CRP halves every 18-20 hours once the cause resolves. It typically returns to normal within a week of recovery.
Frequently asked questions
Do I need to fast for a CRP test?
No, fasting is not required for a CRP measurement. You can have blood drawn at any time of day.
Can stress raise my CRP level?
Chronic stress can contribute to low-grade inflammation, which may slightly raise CRP. Short-term, acute stress usually has no direct effect on your CRP.
How quickly does CRP drop after an infection?
CRP drops fairly quickly once the cause resolves. The value roughly halves every 18 to 20 hours, so CRP is usually back to normal within a week of recovery.
What is the difference between CRP and the sedimentation rate?
Both are inflammation markers. CRP responds faster to inflammation and also falls faster, while the sedimentation rate changes more slowly. Doctors sometimes review them together.
Can a common cold raise my CRP?
Yes, a cold or flu can also raise CRP. Viral infections usually cause a milder rise than bacterial infections.
What is a dangerously high CRP level?
There is no fixed cut-off for danger. Values above 50 to 100 mg/L more often fit a serious infection or inflammation. A significantly elevated value is a reason to discuss it with your GP.
Can a CRP value be too low?
No, a low CRP value is not harmful. A value below 5 mg/L falls within the normal range and usually indicates that no significant inflammation is present.
Do medications affect my CRP level?
Some medications, such as anti-inflammatory drugs, can affect CRP. For that reason it helps to mention which medications you use when having a blood test.
How often can you have your CRP measured?
There is no fixed rule for how often to measure CRP. How often is worthwhile depends on your situation and is something to discuss with your GP.
Does a CRP value say anything about cancer?
CRP is not a cancer test. The value can be elevated in a wide range of conditions and says nothing specific about cancer on its own. Discuss persistently elevated values with your GP.
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