C-reactive protein (CRP) concentration in 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 assess inflammation, often used to monitor conditions like infections, autoimmune diseases, or heart disease risk."]
Key facts at a glance
- LOINC
- 109805-2
- Short code
- HCV RNA Msmt CSF
- Synonyms
- HCV RNA Msmt CSF
- Category
- chemistry
- Sample
- csf
- Container
- Sterile tube
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 86803
- Specimen volume
- 1-2 mL
- Stability
- Immediate analysis required, Refrigerated: 1h
- Hemolysis max
- 200
- TAT
- 4–24 hours
- Order
- routine
Why Is This Test Done? Your doctor may order a CRP test to look for inflammation in your body, help diagnose an infection, or check how well treatment for a condition such as arthritis or another inflammatory disease is working over time.
Your healthcare provider may order a CRP test to check for signs of inflammation, monitor chronic conditions, or evaluate symptoms like fever, joint pain, or swelling. It can also help determine if you’re at risk for heart disease or other inflammatory disorders.
What to Expect Before the Test: In most cases, no special preparation is needed for a CRP test, and you can usually follow your normal routine. Tell your doctor about any medicines, vitamins, or supplements you take, because some drugs can affect your results.
No special preparation is usually needed. You may be asked to fast for 8–12 hours before the test if it’s part of a lipid panel, but fasting isn’t required for CRP alone. Bring any medications or questions to your appointment.
How the Test Is Performed: A trained health care professional will draw a small sample of blood from a vein in your arm, usually on the inside of your elbow. It takes only a few minutes, and you may feel a quick sting or pinch when the needle goes in.
A healthcare professional will draw blood from a vein in your arm using a small needle. You may feel a slight pinch, but it usually doesn’t cause discomfort. The blood sample is then sent to a lab for analysis.
What the Results Mean: Higher-than-normal CRP levels often mean there is inflammation somewhere in your body, which can be caused by infection, injury, or a chronic condition. Your doctor will interpret your result along with your symptoms and any other tests you have had.
Results are reported in milligrams per liter (mg/L). Higher than normal levels may indicate inflammation, infections, or certain diseases. Your doctor will interpret results based on your symptoms and medical history.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance
Short name
CRP (Serum/Plasma)
Frequently asked questions
CRP is a marker of acute or chronic inflammation. High levels can signal infections (like pneumonia or urinary tract infections), autoimmune diseases (like rheumatoid arthritis), or conditions that increase heart disease risk (e.g., atherosclerosis). Low levels may suggest no active inflammation, but they don’t rule out all causes.
A CRP test helps your doctor track inflammation in your body, which can be linked to infections, autoimmune conditions, or long-term risks like heart disease. It’s often used alongside other tests to guide treatment decisions.
No fasting is required for a CRP test alone, but if it’s part of a lipid panel (like cholesterol tests), you’ll need to fast for 8–12 hours. Always follow your doctor’s instructions.
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