C-reactive protein (CRP) by nephelometry
This test measures the level of C-reactive protein in your blood, a protein produced by your liver in response to inflammation.
["CRP helps identify and monitor inflammation in your body."]
Key facts at a glance
- LOINC
- 95217-6
- Short code
- nRBC NFr Stem prod Manual
- Synonyms
- nRBC NFr Stem prod Manual
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 4.2
- Ref high
- 5.9
- Critical range
- 2 N/A – 7 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- manual-count
- CPT
- 85041
- SNOMED
- 900000000000003001
- 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?
Doctors may order CRP testing to check for signs of inflammation, which can occur due to infections, injuries, autoimmune conditions, or other health issues. It’s often used alongside other tests to assess overall health or diagnose specific conditions like heart disease, arthritis, or 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-thinning medication or have a history of bleeding issues, let your healthcare provider know beforehand.
What Happens During the Test?
A healthcare professional will collect a small amount of blood from a vein in your arm. The blood is then sent to a lab where it’s analyzed using a nephelometry method to measure CRP levels.
What Are the Results Mean?
Results show the concentration of CRP in milligrams per liter (mg/L). Higher levels may indicate inflammation, while lower levels suggest minimal or no inflammation. Your doctor will interpret the results in the context of your medical history and other tests.
Reference range
Adult males: 4.2-5.9; Females: 3.8-5.1 x 10^12/LN/A
No special preparation required. Stay well hydrated.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Elevated CRP levels can signal inflammation, which may be linked to infections, autoimmune diseases, or chronic conditions like heart disease or arthritis. While CRP doesn’t diagnose a specific condition, it helps guide treatment decisions and monitor disease activity. Always discuss results with your healthcare provider.
Short name
CRP
Frequently asked questions
How long does it take to get CRP test results?
Can diet or exercise affect CRP levels?
Is CRP testing painful?
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