C-reactive protein (CRP) by nephelometry (serum/plasma)
This blood test measures the level of C-reactive protein, a protein produced by your liver in response to inflammation in your body.
["CRP helps track inflammation, often used to monitor conditions like infections, autoimmune diseases, or after surgery."]
Key facts at a glance
- LOINC
- 92965-3
- Short code
- M catarrhalis DNA Spt NAA+non-prb-NCncRng
- Synonyms
- M catarrhalis DNA Spt NAA+non-prb-NCncRng
- Category
- chemistry
- Sample
- sputum
- Container
- Sterile sputum container
- 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
- Method
- non-probe-amp-tar
- CPT
- 85610
- SNOMED
- 396252006
- Specimen volume
- 3-5 mL
- Stability
- Room temperature: 2h, Refrigerated: 24h
- TAT
- 4–24 hours
- Order
- routine
Why Is This Test Done?
Your healthcare provider may order this test to check for signs of inflammation, monitor chronic conditions like rheumatoid arthritis or lupus, evaluate infections, or assess how your body is responding to treatment for certain illnesses.
What Does a High or Low Level Mean?
Elevated CRP levels often indicate inflammation, infections, or other health issues. Very low levels may suggest no active inflammation, but they can also occur in certain genetic conditions or with certain medications.
Sample Collection and Preparation
A blood sample is taken from a vein in your arm. The blood is sent to a lab where it is processed into serum or plasma for testing. No special preparation is needed, but you may be asked to fast for a few hours before the test if instructed by your provider.
What to Expect During the Test
The process is quick and typically painless. You may feel a slight pinch when the needle is inserted, but most people tolerate it well. You can usually resume normal activities immediately after.
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 is a marker for inflammation and is used broadly in medicine to guide treatment decisions, monitor disease progression, and assess treatment effectiveness. It can help identify underlying causes of symptoms like fever, joint pain, or fatigue that may not have a clear diagnosis otherwise.
Short name
CRP (Serum/Plasma)
Frequently asked questions
How often should I get this test?
What are the typical reference ranges?
Can I eat or drink before this test?
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