C-reactive protein (CRP) concentration in serum/plasma
This blood test measures the level of C-reactive protein, a protein produced by the liver in response to inflammation in your body.
["CRP helps identify inflammation, often used to monitor conditions like infections or autoimmune diseases."]
Key facts at a glance
- LOINC
- 71528-4
- Short code
- PERSONNELJOBDESCRIPTION
- Synonyms
- —
- Category
- coagulation
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 0.8
- Ref high
- 1.2
- Critical range
- — – 5 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- esrd
- CPT
- 85610
- SNOMED
- 396252006
- 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 healthcare provider may order this test to check for signs of inflammation, monitor chronic conditions (such as arthritis or heart disease), or evaluate responses to treatments. It can also help diagnose infections or other inflammatory conditions.
What to Expect Before the Test
No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the test if it’s part of a broader metabolic or liver assessment. Avoid strenuous activity or aspirin/ibuprofen 24 hours prior, as they can affect results.
What Happens During the Test?
A healthcare professional will draw blood from a vein in your arm. You may feel a slight pinch, but the process is quick. The blood sample is sent to a lab for analysis.
What the Results Mean
Higher-than-normal CRP levels may indicate inflammation, infections, or other health issues. Lower levels suggest reduced inflammation. Your results will be compared to your clinical picture and other tests for accurate interpretation.
Reference range
INR: 0.8-1.2 (warfarin: 2.0-3.0)N/A
Inform your healthcare provider if you are taking blood thinners. No special preparation required.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance: CRP is a marker for systemic inflammation and is used broadly to assess risk for cardiovascular disease, guide treatment decisions in autoimmune disorders, or monitor disease activity in conditions like rheumatoid arthritis or sepsis.
Short name
CRP (Serum/Plasma)
Frequently asked questions
How long does it take to get my CRP test results?
Can diet or exercise affect CRP levels?
Is CRP always elevated in infections?
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