C-reactive protein (CRP) concentration, plasma
This test measures the level of C-reactive protein in your blood plasma, a protein produced by the liver that rises in response to inflammation or infection.
["CRP helps doctors assess inflammation, guiding treatment for conditions like infections, autoimmune diseases, or heart disease."]
Key facts at a glance
- LOINC
- 76588-3
- Short code
- M catarr g1b XXX.tiss NAA+probe
- Synonyms
- M catarr g1b XXX.tiss NAA+probe
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- 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 Is This Test Done?
Your doctor may order this test to check for signs of inflammation, monitor chronic conditions like arthritis or heart disease, or evaluate responses to treatments. It can also help diagnose infections or identify risks for conditions like heart attacks or stroke.
What to Expect Before the Test
No special preparation is needed, but you may be asked to fast for 8–12 hours before the test if it involves drawing blood from a vein. Wear comfortable clothing and bring any medications you’re currently taking.
How the Test Works
A healthcare professional will take a blood sample from a vein in your arm. The blood is then processed to separate plasma, where CRP levels are measured using an immunoassay method to detect and quantify the protein.
What the Results Mean
Results are typically reported in milligrams per liter (mg/L). Higher than normal levels may indicate inflammation, infection, or an underlying health issue. Your doctor will interpret results in the context of your medical history and symptoms.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance: CRP is a key marker for inflammation. Elevated levels often signal infections, autoimmune disorders, or other inflammatory conditions. It’s also used to monitor disease activity or response to treatment in conditions like rheumatoid arthritis or cardiovascular disease. While not specific to a single cause, CRP helps guide decisions about further testing or treatment adjustments.
Short name
CRP (Plasma)
Frequently asked questions
What causes CRP levels to be higher than usual?
How often should I get this test?
Can diet or lifestyle 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