C-reactive protein, serum concentration (high-sensitivity)
This test measures a protein called C-reactive protein (CRP) in your blood. CRP is produced by your liver in response to inflammation, helping your body fight infections and injuries.
["CRP helps track inflammation, which can signal underlying health issues."]
Key facts at a glance
- LOINC
- 79156-6
- Short code
- COLDAGG37
- Synonyms
- CA 1h p Inc Titr Ser Inc
- Category
- chemistry
- Sample
- serum
- Container
- Serum separator tube (SST) or red-top tube, pre-warmed to 37°C
- Units
- N/A
- Ref low
- 0
- Ref high
- 1
- Critical range
- — – 1000 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- deg-c-incubation
- CPT
- 86157
- SNOMED
- 2490004
- Specimen volume
- 1-2 mL serum
- Stability
- Serum stable at 37°C for 4 hours after separation; if delayed, freeze at -20°C for up to 7 days; do not refrigerate
- Hemolysis max
- 100
- Lipemia max
- 100
- 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 conditions like heart disease, autoimmune disorders, or infections, or evaluate how your body responds to treatments for these conditions. High levels of CRP can sometimes indicate conditions like arthritis, heart attacks, or other inflammatory diseases.
What to Expect Before the Test
No special preparation is needed for this test. You may have a small needle inserted into a vein in your arm to draw blood. The process usually takes a few minutes. If you’re on blood thinners or have a history of bleeding issues, let your provider know.
What the Results Mean
CRP levels can vary depending on your health status. While reference ranges differ by lab, higher than normal levels may suggest inflammation. Your provider will interpret the results in the context of your medical history and other tests.
Common Conditions Monitored
This test is often used to monitor conditions such as cardiovascular disease, rheumatoid arthritis, lupus, or other inflammatory diseases. It can also help assess the effectiveness of treatments aimed at reducing inflammation.
Reference range
Negative or titer <1:64 at 37°C; clinically significant cold agglutinin titers are typically ≥1:64, with high significance at ≥1:256N/A
No fasting required. Sample should be kept at 37°C from collection through separation to prevent cold-induced agglutination that could interfere with test results.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance: CRP as a Marker of Inflammation
Short name
hs-CRP
Frequently asked questions
What causes elevated CRP levels?
How often should I get this test?
Can diet or 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 14, 2026. · Read our editorial policy