C-reactive protein (CRP) mass concentration in serum/plasma
This test measures the amount 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
- 83085-1
- Short code
- CEA
- Synonyms
- CEA SerPl IA-mCnc
- Category
- chemistry
- Sample
- serum
- Container
- Serum separator tube (SST) or red-top tube; plasma acceptable in lithium heparin or EDTA tube
- Units
- N/A
- Ref low
- 0
- Ref high
- 3
- Critical range
- — – 20 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–99 years
- Method
- Immunoassay
- CPT
- 82378
- SNOMED
- 82966005
- Specimen volume
- 1.0 mL serum or plasma (minimum 0.5 mL)
- Stability
- Room temperature: 8 hours; Refrigerated (2-8°C): 7 days; Frozen (-20°C or below): 3 months. Avoid repeated freeze-thaw cycles.
- Hemolysis max
- 100
- Lipemia max
- 150
- Icterus max
- 25
- TAT
- 4–24 hours
- Order
- routine
Why Is This Test Done?
Your healthcare provider may order this test to check for inflammation, monitor chronic conditions like arthritis or heart disease, or evaluate symptoms such as fever, pain, or swelling that may suggest an infection or other inflammatory process.
What to Expect Before the Test
No special preparation is usually needed. You may be asked to fast for 8–12 hours before the test if it’s part of a broader metabolic or liver panel. Bring any medications you’re taking to your appointment.
During the Test
A healthcare professional will draw blood from a vein in your arm using a small needle. You may feel a brief pinch, but it’s usually over quickly. The blood sample is then sent to a lab for analysis.
After the Test
You can return to your normal activities immediately. There may be a small bruise or redness at the injection site, but this usually fades within a few days. If you experience excessive bleeding, swelling, or pain, contact your provider.
Reference range
Non-smokers: <3.0 ng/mL; Smokers: <5.0 ng/mLN/A
No fasting required. Avoid smoking prior to collection as tobacco use can elevate CEA levels. Inform clinician of any recent imaging studies involving contrast agents.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
CRP (Serum/Plasma)
Frequently asked questions
What Does a High CRP Level Mean?
What Does a Low CRP Level Mean?
How Often Should I Get This Test?
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 11, 2026. · Read our editorial policy