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 in your body.
["CRP helps doctors assess inflammation, often used to monitor conditions like infections, autoimmune diseases, or after surgery."]
Key facts at a glance
- LOINC
- 48421-2
- Short code
- CRP BldC-mCnc
- Synonyms
- CRP BldC-mCnc
- Category
- chemistry
- Sample
- whole-blood
- Container
- Lavender-top (EDTA)
- Units
- N/A
- Ref low
- 0
- Ref high
- 3
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 86140
- Specimen volume
- 3 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
Why Is This Test Done?
Your healthcare provider may order a CRP test to check for signs of inflammation. This can help diagnose conditions like infections (e.g., pneumonia), autoimmune diseases (e.g., rheumatoid arthritis), or to monitor healing after surgery or injury.
What Does a High CRP Level Mean?
Elevated CRP levels often indicate inflammation or infection. While not specific to one condition, it can signal areas needing further investigation, such as infections, injuries, or certain chronic diseases.
What Does a Low CRP Level Mean?
Low CRP levels usually mean there is little to no active inflammation in your body. However, very low levels might also suggest conditions like severe malnutrition or certain immune deficiencies.
How Is This Test Performed?
A small blood sample is taken from a vein, usually in your arm. The blood is then sent to a lab where it is analyzed to measure CRP levels using a sensitive detection method.
Reference range
Normal: <3.0 mg/LN/A
No special preparation required. CRP may be affected by acute illness.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance: CRP is a non-specific marker of inflammation. It is commonly used as a screening tool to identify potential inflammatory processes, guide treatment decisions, or monitor disease activity in conditions like infections, autoimmune disorders, or cardiovascular risk assessment. While CRP does not pinpoint the exact cause of inflammation, it provides valuable context for further evaluation.
Short name
CRP (Serum/Plasma)
Frequently asked questions
What causes CRP levels to change?
How long does it take to get results?
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