C-reactive protein (CRP) by nephelometry (serum/plasma)
This test measures the level of C-reactive protein, a protein produced by the liver in response to inflammation in your body.
["CRP helps doctors identify and monitor inflammation, often used to check for infections, autoimmune conditions, or other inflammatory diseases."]
Key facts at a glance
- LOINC
- 100122-1
- Short code
- C pneum Ab Pnl Ser
- Synonyms
- C pneum Ab Pnl Ser
- 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 CRP is Tested
Doctors may order CRP tests to evaluate symptoms like fever, joint pain, or unexplained swelling. It’s also used to monitor chronic conditions like rheumatoid arthritis or heart disease. Some tests are done as part of routine check-ups to detect early signs of inflammation.
How the Test Works
Your blood sample is taken and analyzed using a nephelometric method, which detects the amount of CRP in your serum or plasma. This test provides a quick result to help track inflammation levels over time.
What to Expect Before the Test
No special preparation is needed for this test. You can eat, drink, or take medications as usual on the day of your visit. If you’re on blood thinners, let your doctor know before the test.
What the Results Mean
Higher CRP levels often indicate inflammation, which could be caused by infections, injuries, or certain diseases. Lower levels suggest minimal inflammation. Your doctor will interpret the results in the context of your symptoms and medical history.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
CRP is a useful marker for diagnosing and managing inflammatory conditions. Elevated levels may signal infections (like pneumonia or sepsis), autoimmune diseases (like lupus or vasculitis), or other inflammatory processes. It’s also used to assess the risk of heart disease and monitor treatment effectiveness in chronic conditions.
Short name
CRP
Frequently asked questions
How often should I get a CRP test?
What are typical CRP reference ranges?
Can diet or exercise affect CRP levels?
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