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 doctors assess inflammation, often used to monitor conditions like infections, autoimmune diseases, or after surgery."]
Key facts at a glance
- LOINC
- 104685-3
- Short code
- DMA 16:0/C16:0 DBS
- Synonyms
- DMA 16:0/C16:0 DBS
- 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 Is This Test Done?
Your healthcare provider may order CRP testing to check for signs of inflammation, monitor chronic conditions like arthritis or heart disease, or evaluate symptoms such as fever, pain, or swelling. It can also help guide treatment decisions or track how well a condition is responding to treatment.
What to Expect Before the Test
No special preparation is needed for this blood test. You may be asked to fast for 8–12 hours before the draw if your lab requires it, but this is not always the case for CRP. Bring any recent medications or supplements you’re taking, as they can sometimes affect results.
What Happens During the Test?
A healthcare professional will insert a small needle into a vein in your arm to draw a blood sample. The process usually takes a few minutes. You may feel a brief pinch, but most people tolerate it well. The blood is then sent to a lab for analysis using nephelometry, a method that measures how much light scatters from particles in the sample.
What Does the Result Mean?
CRP levels vary depending on your health and medical history. Higher than normal levels often indicate inflammation, but they can also be elevated due to stress, infection, or other factors. Your results will be reviewed by a healthcare provider to help diagnose or guide treatment for your specific condition.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
CRP is a marker of systemic inflammation and is widely used in medicine to assess risk for conditions like cardiovascular disease, infections, and inflammatory diseases. While not a definitive test for any single condition, it provides valuable context for doctors to evaluate overall health and guide management plans. Elevated CRP may prompt further testing or adjustments to treatment, such as medications for conditions like rheumatoid arthritis or heart disease.
Short name
CRP
Frequently asked questions
How long does it take to get my CRP test results?
Can CRP levels change based on what I eat or drink?
Is CRP testing safe?
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