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 doctors assess inflammation, often used to monitor conditions like infections, autoimmune diseases, or heart disease."]
Key facts at a glance
- LOINC
- 19169-2
- Short code
- CEA-PL
- Synonyms
- CEA Plr-mCnc
- Category
- chemistry
- Sample
- fluid
- Container
- Sterile, leak-proof, screw-cap container (plain or heparinized); transfer to red-top or SST tube if clotted specimen
- Units
- N/A
- Ref low
- 0
- Ref high
- 5
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- Immunoassay (Chemiluminescent or Electrochemiluminescent)
- CPT
- 82378
- SNOMED
- 395112001
- Specimen volume
- 2-5 mL of pleural fluid
- Stability
- Room temperature: 8 hours; Refrigerated (2-8°C): 7 days; Frozen (-20°C): 3 months. Avoid repeated freeze-thaw cycles.
- Hemolysis max
- 300
- 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, or evaluate symptoms like fever, joint pain, or swelling. It can also help determine if an infection is present or if your body is overreacting to certain conditions.
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 fasting panel, but this depends on your healthcare provider’s instructions. Bring any medications you’re taking.
What Happens 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 usually doesn’t cause significant discomfort. The blood is then sent to a lab for analysis.
What Are Possible Results?
Results are reported in milligrams per deciliter (mg/dL). Higher levels may indicate inflammation, infection, or other health issues, while lower levels may suggest reduced inflammation. Your results will be interpreted by your provider based on your medical history and symptoms.
Reference range
Non-smokers: <2.5 ng/mL; Smokers: <5.0 ng/mLN/A
No fasting required. Patient should be prepared for thoracentesis procedure per institutional protocol. Informed consent must be obtained prior to pleural fluid collection.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
CRP Level
Frequently asked questions
How long does it take to get my CRP test results?
If your test is part of a fasting panel, you’ll need to avoid food and liquids (except water) for 8–12 hours before drawing blood. If it’s a standalone CRP test, no fasting is required. Follow your provider’s specific instructions to ensure accurate results.
Is there anything I should do if my CRP is high?
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