C-reactive protein (CRP) concentration
This test measures the level of C-reactive protein in your blood, a protein produced by your liver in response to inflammation.
["CRP helps doctors assess inflammation, often used to monitor conditions like infections or autoimmune diseases."]
Key facts at a glance
- LOINC
- 103473-5
- Short code
- XR Neck 2V
- Synonyms
- XR Neck 2V
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 22
- Ref high
- 198
- Critical range
- — – 10000 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- xr
- CPT
- 82553
- 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 a CRP test to check for signs of inflammation in your body. This could be due to infections (like pneumonia or urinary tract infections), injuries, or conditions like arthritis or heart disease. It may also be used to monitor how well treatments for these conditions are working.
What Does a High or Low CRP Level Mean?
A higher than normal CRP level often indicates inflammation. Very high levels may suggest severe infections or other serious conditions. A low level usually means there is little to no inflammation, but this can vary depending on your overall health and medical history.
How Is the CRP Test Performed?
A blood sample is taken from a vein, usually in your arm. The sample is sent to a lab where it is analyzed to measure CRP levels using an immunoassay method.
What Are Common Causes of Abnormal CRP Levels?
CRP levels can be elevated due to infections, injuries, surgeries, or certain medical conditions like rheumatoid arthritis, lupus, or heart disease. It can also be affected by factors like smoking, stress, or certain medications.
Reference range
Adult males: 22-198 U/L; Females: 22-198 U/LN/A
No special preparation required. Inform provider of any chest pain or symptoms.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
CRP plays a key role in identifying and monitoring inflammation-related health issues. It can help doctors diagnose conditions early, guide treatment plans, and track progress over time. However, CRP alone is not diagnostic for specific diseases and should be interpreted alongside other test results and clinical findings.
Short name
CRP
Frequently asked questions
What does a CRP test measure?
Can CRP levels change with diet or lifestyle?
How soon after a procedure or injury should I expect CRP levels to change?
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 17, 2026. · Read our editorial policy