C-reactive protein (mass concentration) in serum/plasma
This test measures the level of C-reactive protein, a protein produced by the liver in response to inflammation in your body.
["CRP helps doctors assess inflammation, often used to monitor conditions like infections or autoimmune diseases."]
Key facts at a glance
- LOINC
- 56210-8
- Short code
- CATDNGG4
- Synonyms
- Cat Dander IgG4-mCnc
- Category
- chemistry
- Sample
- serum
- Container
- Serum separator tube (SST) or red-top vacutainer tube
- Units
- N/A
- Ref low
- 0
- Ref high
- 0.35
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 1–99 years
- Method
- Immunoassay (ELISA or Fluorescent Enzyme Immunoassay)
- CPT
- 86001
- SNOMED
- 39512008
- Specimen volume
- 0.5-1 mL serum
- Stability
- Serum stable for 7 days at 2-8°C; for longer storage, freeze at -20°C or below; avoid repeated freeze-thaw cycles
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 24–72 hours
- Order
- routine
Why Is This Test Done?
Your doctor may order a CRP test to check for signs of inflammation, monitor chronic conditions (such as rheumatoid arthritis or heart disease), or evaluate how well you’re responding to treatment for an infection or illness.
Common Uses in Healthcare
CRP is commonly used to screen for infections, track autoimmune diseases, or identify risks for conditions like heart disease or certain cancers.
What to Expect Before the Test
No special preparation is needed, but you may be asked to fast for 8–12 hours if your blood is drawn early in the morning for accuracy.
What Happens During the Test?
A healthcare provider will draw blood from a vein in your arm. You may feel a slight pinch, but it usually takes only a few minutes.
Reference range
Reference ranges vary by laboratory and methodology; results typically reported as negative (<0.35 mg/L), equivocal (0.35-0.50 mg/L), or positive (>0.50 mg/L) for allergen-specific IgG4 antibodiesN/A
No special patient preparation required. Patient should be well-hydrated prior to venipuncture. Inform clinician of any current antihistamine or immunosuppressive therapy use as it may affect antibody levels.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Elevated CRP levels often indicate inflammation, infections, or autoimmune activity. While not specific to a single condition, it helps guide treatment decisions and monitor disease progression.
Short name
CRP (Serum/Plasma)
Frequently asked questions
How long does it take to get results?
Can diet or exercise affect CRP levels?
Is CRP the same as a white blood cell count?
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