Serum/plasma concentration of C-reactive protein (CRP)
This test measures the level of C-reactive protein in your blood, which is a marker of inflammation.
["CRP helps doctors assess inflammation, often used to monitor conditions like infections or autoimmune diseases."]
Key facts at a glance
- LOINC
- 90417-7
- Short code
- CDT-APOC3
- Synonyms
- CDT + Apo C-III Pnl SerPl
- Category
- chemistry
- Sample
- serum
- Container
- Serum separator tube (SST) or red-top tube with no anticoagulant
- Units
- N/A
- Ref low
- 1.7
- Ref high
- 2
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 18 years
- Method
- Capillary electrophoresis and immunonephelometry or immunoturbidimetry
- CPT
- 80377 (CDT), 82172 (Apolipoprotein)
- SNOMED
- 104686000
- Specimen volume
- 2-5 mL of blood (minimum 1 mL serum)
- Stability
- Serum stable at room temperature for 8 hours, refrigerated (2-8°C) for 7 days, frozen at -20°C or below for up to 3 months; avoid repeated freeze-thaw cycles
- Hemolysis max
- 100
- Lipemia max
- 150
- Icterus max
- 50
- TAT
- 24–72 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 response to treatment for inflammatory diseases.
What Does a High CRP Level Mean?
Elevated CRP levels often indicate inflammation in the body, which can be caused by infections, injuries, or certain diseases. It doesn’t always pinpoint the exact cause but helps guide treatment decisions.
What Does a Low CRP Level Mean?
Low CRP levels usually mean there is little to no inflammation. However, very low levels might raise concerns if you have a known inflammatory condition, as they could indicate poor control of the disease or a lack of response to treatment.
Common Conditions Monitored with CRP
CRP is commonly used to monitor conditions such as cardiovascular disease, infections (like pneumonia or sepsis), and inflammatory disorders like arthritis or inflammatory bowel disease.
Reference range
Carbohydrate-deficient transferrin (CDT): <1.7% (normal), 1.7-2.0% (borderline), >2.0% (elevated suggesting chronic alcohol use); Apolipoprotein C-III: 5-15 mg/dL (varies by isoform and laboratory method)N/A
No fasting required. Patients should abstain from alcohol for at least 24 hours prior to collection, though recent alcohol intake is relevant for clinical interpretation. Avoid sample collection during acute illness, surgery, or hospitalization as these may falsely elevate CDT.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
CRP Level
Frequently asked questions
What Does a CRP Test Tell Me About My Health?
How Often Should I Get a CRP 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 15, 2026. · Read our editorial policy