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 assess inflammation, often used to monitor conditions like infections or autoimmune diseases.
Key facts at a glance
- LOINC
- 106058-1
- Short code
- CT + NG + TV rRNA Pnl Vagina NAA+probe
- Synonyms
- CT + NG + TV rRNA Pnl Vagina 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
- CPT
- 86038
- 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
What Is C-Reactive Protein (CRP) Used For?
CRP is primarily used to detect and monitor inflammation. High levels may signal infections, injuries, or conditions like rheumatoid arthritis, lupus, or heart disease. It can also help track how well treatments are working for certain inflammatory conditions.
How Is CRP Tested?
The test involves drawing blood from a vein in your arm. The blood is then processed to measure CRP levels using a specialized nephelometry method, which detects the protein’s presence in your serum or plasma.
What Does a CRP Test Tell You?
While CRP doesn’t specify the cause of inflammation, elevated levels often point to an active inflammatory process. Very high levels may indicate severe infections or complications from conditions like sepsis. Low or normal levels suggest minimal inflammation, but they don’t rule out other causes.
When Might You Need a CRP Test?
Your doctor may order a CRP test if you have symptoms like fever, joint pain, or unexplained fatigue, or if you’re at risk for conditions like heart disease, autoimmune disorders, or chronic infections.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
CRP is a general marker of inflammation and is used to guide treatment decisions, monitor disease activity, and assess response to therapy in conditions like arthritis, cardiovascular disease, or post-surgical recovery. It’s not diagnostic on its own but often helps narrow down possible causes of symptoms.
Short name
CRP
Frequently asked questions
Why might my CRP test be higher than usual?
What should I do if my CRP test is elevated?
Can CRP test results change over time?
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