C-reactive protein (mass concentration) in serum/plasma
This test measures the level of C-reactive protein, a protein produced by the liver in response to inflammation or infection in your body.
["CRP helps doctors assess inflammation and identify possible infections or conditions like autoimmune diseases."]
Key facts at a glance
- LOINC
- 8181-0
- Short code
- Cr Sal-mCnc
- Synonyms
- Cr Sal-mCnc
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- 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?
Your healthcare provider may order this test to monitor inflammation, check for infections, evaluate autoimmune conditions, or assess response to treatment for conditions like arthritis or heart disease. It can also be used to screen for certain risks, such as cardiovascular disease.
What to Expect Before the Test
No special preparation is usually needed. You may be asked to fast for 8–12 hours before the test if it involves drawing blood from a vein. If you’re taking blood from a finger, no fasting is required.
What Happens During the Test?
A healthcare professional will draw blood from a vein in your arm using a small needle. You may feel a brief pinch, but it usually doesn’t cause significant discomfort. The blood sample is then sent to a lab for analysis.
What Are Possible Results?
Results are typically reported in milligrams per liter (mg/L). Higher than normal levels may indicate inflammation, infection, or other health issues. Your results will be discussed with your doctor to determine next steps.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance: CRP is a marker for inflammation. Elevated levels can signal infections (such as pneumonia or urinary tract infections), autoimmune diseases (like rheumatoid arthritis), or other inflammatory conditions. It’s also used to monitor treatment effectiveness or screen for risks like heart disease.
Short name
CRP (Serum/Plasma)
Frequently asked questions
What does a high CRP level mean?
Can diet or exercise affect CRP levels?
Is CRP the same as a white blood cell count?
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