C-reactive protein (CRP) 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 identify and monitor inflammation, often used to check for infections, autoimmune conditions, or other health concerns."]
Key facts at a glance
- LOINC
- 111874-4
- Short code
- Insertion time Endscpy
- Synonyms
- Insertion time Endscpy
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 0
- Ref high
- 17
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- endoscopy
- 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 CRP Testing Matters
CRP is a marker that rises when your body is fighting inflammation. It can appear in blood tests to help diagnose conditions like infections, heart disease, or inflammatory diseases such as rheumatoid arthritis. CRP levels can also be checked after surgery or during recovery to ensure inflammation is under control.
What to Expect Before the Test
No special preparation is usually needed for this test. You may be asked to fast for 8–12 hours before the draw if your lab uses a specific method for CRP measurement. Your doctor or lab technician will explain any instructions if needed. The test is typically done by drawing blood from a vein in your arm.
What the Results Mean
CRP results are often reported in milligrams per liter (mg/L). Higher levels may indicate inflammation, infections, or other health issues. Your doctor will interpret the results in the context of your overall health and medical history.
Common Conditions Monitored
CRP is commonly used to monitor conditions like infections (e.g., pneumonia, urinary tract infections), autoimmune diseases (e.g., lupus, rheumatoid arthritis), and to assess risk for heart disease. It can also help track how well treatment is working for these conditions.
Reference range
NCBI: NSE 0-17 ng/mLN/A
No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Elevated CRP levels can signal an active inflammatory process, guiding treatment decisions for infections, autoimmune disorders, or post-surgical monitoring. While CRP is not specific to any single condition, it provides a broad measure of systemic inflammation that can prompt further investigation or adjustments to care plans.
Short name
CRP (Serum/Plasma)
Frequently asked questions
What causes CRP levels to change?
How often should CRP be checked?
Can CRP levels be affected by diet or exercise?
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 17, 2026. · Read our editorial policy