C-reactive protein (CRP) by nephelometry
This test measures the level 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
- 46776-1
- Short code
- CPT2/CACT DBS-Imp
- Synonyms
- CPT2/CACT DBS-Imp
- Category
- coagulation
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 0.8
- Ref high
- 1.2
- Critical range
- — – 5 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 85610
- SNOMED
- 396252006
- 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 doctor may order a CRP test to check for signs of inflammation, monitor chronic conditions like rheumatoid arthritis or lupus, or evaluate symptoms such as fever, joint pain, or unexplained fatigue. It can also help assess the risk of heart disease or guide treatment decisions for infections.
What to Expect Before the Test
No special preparation is needed for this blood test. You may have a small needle inserted into your arm to draw a blood sample. If you’re on blood thinners, let your doctor know before the test.
What the Results Mean
CRP levels vary depending on your health and condition. Higher levels may indicate inflammation, while lower levels suggest minimal or no inflammation. Your doctor will interpret results in the context of your medical history and other tests.
Common Conditions Monitored
CRP is often used to track conditions like infections (e.g., pneumonia, urinary tract infections), autoimmune diseases (e.g., lupus, rheumatoid arthritis), or to assess cardiovascular risk. It can also help monitor responses to treatments.
Reference range
INR: 0.8-1.2 (warfarin: 2.0-3.0)N/A
Inform your healthcare provider if you are taking blood thinners. No special preparation required.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance: CRP serves as a general marker for inflammation. While not specific to a single condition, elevated CRP can signal underlying inflammation that may require further investigation, such as additional tests or medical evaluation.
Short name
CRP
Frequently asked questions
What causes CRP levels to change?
How often should I get this test?
Can diet or lifestyle affect CRP levels?
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