C-reactive protein (CRP) in plasma or serum
This blood test measures the level of C-reactive protein, a protein produced by the liver in response to inflammation in your body.
["CRP helps doctors assess inflammation, which can signal infections, injuries, or other health conditions."]
Key facts at a glance
- LOINC
- 107577-9
- Short code
- K.pnm grp DNA Fld Ql NAA+n-prb
- Synonyms
- K.pnm grp DNA Fld Ql NAA+n-prb
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- non-probe-amp-tar
- 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 CRP is Tested
Doctors may order a CRP test to monitor conditions like infections (e.g., pneumonia, urinary tract infections), autoimmune diseases (e.g., rheumatoid arthritis), heart disease risk, or to check for signs of inflammation after surgery or trauma. It can also help track how well treatments are working for certain conditions.
How the Test Works
A small blood sample is taken from a vein, usually in your arm. The sample is sent to a lab where it is analyzed using a sensitive immunoassay method to detect CRP levels.
What to Expect Before the Test
You can eat, drink, or take medications as usual on the day of the test. Avoid heavy exercise or strenuous activities before the test, as they might temporarily raise CRP levels. If you’re on blood thinners, inform your healthcare provider before the procedure.
What to Expect During the Test
The test involves a quick needle stick to draw blood. You may feel a slight pinch, but it usually takes only a few seconds. Most people experience minimal discomfort. You can resume normal activities immediately after.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Elevated CRP levels often indicate inflammation, which can be linked to infections, inflammatory diseases, or other systemic conditions. While CRP doesn’t diagnose a specific condition, it helps guide treatment decisions and monitor disease activity. Very high levels may signal severe infections or complications from chronic diseases.
Short name
CRP
Frequently asked questions
How long does it take to get results?
Can diet or exercise affect CRP levels?
Is CRP always elevated in infections?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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