C-reactive protein, mass concentration (serum/plasma)
This test measures the amount of C-reactive protein in your blood. CRP is a protein produced by your liver in response to inflammation or infection.
["CRP helps your doctor assess inflammation in your body."]
Key facts at a glance
- LOINC
- 63082-2
- Short code
- CAYIGG
- Synonyms
- Cayenne IgG-mCnc
- Category
- chemistry
- Sample
- serum
- Container
- Serum separator tube (SST) or red-top tube
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- Immunoassay (e.g., ELISA, ImmunoCAP, or similar quantitative IgG antibody detection method)
- CPT
- 86001
- SNOMED
- 395143001
- Specimen volume
- 1-2 mL of serum
- Stability
- Serum stable for 7 days at 2-8°C; for longer storage, freeze at -20°C or below
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 24–168 hours
- Order
- routine
Why Is This Test Done?
Your doctor may order a CRP test to check for signs of inflammation, monitor conditions like arthritis, infections, or heart disease, or evaluate responses to treatments. It can also help identify risks for certain health issues before symptoms appear.
What to Expect During the Test
A small blood sample is taken from a vein in your arm. You may feel a slight pinch, but it usually doesn’t cause discomfort. The test is quick and doesn’t require special preparation.
What the Results Mean
Higher than normal levels of CRP may indicate inflammation, infections, or other health problems. Lower levels suggest minimal inflammation. Your doctor will interpret the results in the context of your overall health and medical history.
Common Conditions Monitored
CRP is often used to monitor conditions such as rheumatoid arthritis, lupus, heart disease, or to check for infections like pneumonia or sepsis. It can also help track how well treatments are working.
Reference range
Reference ranges vary by laboratory and methodology. Results are typically reported in mass/volume units (e.g., mg/L or μg/mL). Negative or low results generally indicate no significant sensitization. Consult laboratory-specific reference ranges for clinical interpretation.N/A
No special preparation required. Fasting is not necessary. Patient should be on a regular diet including suspected food items prior to testing for optimal sensitivity of IgG detection.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance: CRP is a marker for inflammation and can signal underlying health issues. Elevated levels may prompt further testing or adjustments to treatment plans, while consistently low levels may indicate good overall health or effective management of conditions causing inflammation.
Short name
CRP (Serum/Plasma)
Frequently asked questions
What causes CRP levels to change?
How often should I get this test?
Can lifestyle changes 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 16, 2026. · Read our editorial policy