C-reactive protein (high-sensitivity) in serum/plasma
This test measures a protein produced by the liver in response to inflammation, helping assess low-grade inflammation or risk of cardiovascular disease.
["hs-CRP helps track subtle inflammation that may not show up in other tests."]
Key facts at a glance
- LOINC
- 94266-4
- Short code
- CD11/CD18
- Synonyms
- CD11a + CD11b + CD18 Pnl Bld
- Category
- chemistry
- Sample
- serum
- Container
- EDTA (lavender-top) tube; sodium heparin (green-top) tube is also acceptable for flow cytometry
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–99 years
- Method
- Flow cytometry immunophenotyping using fluorescently labeled monoclonal antibodies directed against CD11a, CD11b, and CD18 integrin subunits
- CPT
- 86356
- SNOMED
- 39517008
- Specimen volume
- 3-5 mL of whole blood; minimum 1 mL for pediatric patients
- Stability
- Room temperature: 24 hours. Refrigerated (2-8°C): 48 hours. Do not freeze. Specimen should be processed within 24 hours for optimal viability and marker integrity.
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 48–96 hours
- Order
- routine
Why Is This Test Done?
Your healthcare provider may order hs-CRP to evaluate your risk for heart disease, monitor chronic conditions like arthritis or diabetes, or check for signs of inflammation after surgery or injury. It’s often used alongside other tests to guide treatment decisions.
What to Expect Before the Test
No special preparation is needed. You’ll provide a blood sample, usually drawn from your arm. Avoid strenuous activity or infections for 24 hours before testing, as they can affect results.
What the Results Mean
Results are not always interpreted alone; they’re compared to your overall health and other test findings. Higher levels may signal inflammation, while lower levels may indicate reduced risk. Your doctor will discuss what your specific result means for you.
Common Causes of Abnormal Results
Elevated hs-CRP can occur with infections, autoimmune diseases, obesity, or smoking. Low levels may be normal if you have minimal inflammation. Conditions like kidney disease or certain medications can also influence results.
Reference range
Qualitative test. Normal result: normal expression of CD11a, CD11b, and CD18 on neutrophils, lymphocytes, and monocytes. Reference patterns are interpreted against established isotype controls. Decreased or absent expression is suggestive of leukocyte adhesion deficiency (LAD).N/A
No fasting required. Avoid recent blood transfusion within 48 hours if possible, as this may affect leukocyte phenotype. Inform the laboratory of any immunosuppressive therapy.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
hs-CRP
Frequently asked questions
What does hs-CRP measure?
How often should I get this test?
Can lifestyle changes affect hs-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