C-reactive protein (CRP) in fluid (e.g., synovial, pleural, or peritoneal)
This test measures the level of C-reactive protein, a protein produced by the liver in response to inflammation, in a body fluid sample (such as joint, chest, or abdominal fluid).
["Helps assess inflammation beyond blood tests in fluid collections."]
Key facts at a glance
- LOINC
- 109881-3
- Short code
- C immitis Ab Msmt Fld
- Synonyms
- C immitis Ab Msmt Fld
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- 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 This Test Might Be Ordered
Your doctor may recommend this test if you have symptoms of inflammation in a specific body cavity (e.g., joint pain, swelling, or fluid buildup in the chest or abdomen) and suspect conditions like arthritis, infection, or other inflammatory diseases. Fluid samples are often taken during procedures like arthrocentesis or thoracentesis.
What to Expect Before the Test
No special preparation is needed for this test. The fluid sample is typically collected during a medical procedure, such as draining fluid from a joint, chest, or abdomen. You may experience mild discomfort or bruising at the site.
What the Test Results Mean
Elevated CRP levels in fluid may indicate inflammation, infection, or other conditions causing fluid accumulation. However, results alone don’t diagnose a specific condition—your doctor will consider symptoms, physical exam, and other tests.
Common Conditions Monitored
This test is often used to monitor conditions like rheumatoid arthritis, gout, infections (e.g., abscesses), or inflammatory diseases such as pancreatitis or pleural effusion.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
CRP in Body Fluid
Frequently asked questions
What does a high CRP level in fluid mean?
The fluid is usually collected during a medical procedure, such as draining fluid from a joint (e.g., knee or shoulder), chest (thoracentesis), or abdomen (paracentesis). You may feel slight discomfort, but it’s generally quick and done under sterile conditions.
Results may take a few days to a week, depending on lab processing and your healthcare provider’s workflow. Your doctor will contact you once they’re ready to discuss them.
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