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
- 16503-5
- Short code
- CRP Fld-mCnc
- Synonyms
- CRP Fld-mCnc
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 0
- Ref high
- 3
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 86140
- 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 like rheumatoid arthritis or lupus, or evaluate your response to treatment. It can also help identify infections or other inflammatory processes in your body.
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 drawn from a blood sample, but this depends on your lab’s protocol. Bring any medications or supplements you’re taking to your appointment.
How the Test Is Performed
A healthcare professional will draw blood from a vein in your arm using a small needle. The blood sample is then sent to a lab for analysis. The test measures CRP levels in your serum or plasma.
What the Results Mean
Higher CRP levels often indicate inflammation, which can be caused by infections, injuries, or autoimmune diseases. Lower levels suggest minimal inflammation. Your results will be compared to standard reference ranges provided by your lab.
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.
Elevated CRP is a general marker of inflammation and can guide treatment decisions, such as adjusting medications for conditions like arthritis or monitoring healing after surgery. It’s not specific to one disease but helps track overall inflammatory activity in the body.
Short name
CRP (Serum/Plasma)
Frequently asked questions
What causes CRP levels to change?
How long does it take to get results?
Can I eat or drink before 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 16, 2026. · Read our editorial policy