C-reactive protein (CRP) with high-sensitivity immunoassay (hs-CRP)
This blood test measures a protein called C-reactive protein, which your body produces in response to inflammation. It helps assess low-level inflammation that may not be obvious from other tests.
Helps track subtle inflammation in your body, often linked to conditions like heart disease or autoimmune disorders.
Key facts at a glance
- LOINC
- 105786-8
- Short code
- OXA24/40
- Synonyms
- blaOXA-24+blaOXA-40 Ct Bld +Qn NAA+prb
- Category
- chemistry
- Sample
- whole-blood
- Container
- Positive blood culture bottle (aerobic or anaerobic) with sufficient volume for subculture and molecular testing
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- probe-amp-tar
- CPT
- 87150
- SNOMED
- 43461000119100
- Specimen volume
- 1-2 mL aliquot from positive blood culture broth
- Stability
- Stable for 24 hours at 2-8°C after removal from blood culture instrument; can be frozen at -80°C for prolonged storage
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 1–4 hours
- Order
- routine
Why Is This Test Done?
Your doctor may order this test to monitor chronic conditions like arthritis, heart disease, or other inflammatory disorders. It’s also used to check for signs of infection or inflammation after surgery, injury, or during treatment for conditions like cancer.
What Does a High or Low Result Mean?
Elevated CRP levels often indicate inflammation, but they can also rise with infections, injuries, or certain medications. Very low levels may suggest a reduced immune response or certain medical conditions.
How Is This Test Performed?
A small blood sample is taken from your arm, usually in a lab setting. The test measures CRP concentration using a sensitive immunoassay method, which detects even small amounts of the protein.
What Should You Expect Before the Test?
No special preparation is needed, but inform your doctor about any medications you’re taking, as some may affect results. Avoid strenuous activity 24 hours before the test if instructed.
Reference range
Cycle threshold (Ct) value is reported for positive blood culture samples. Results are interpreted as Detected or Not Detected based on amplification curves. Lower Ct values indicate higher bacterial load.N/A
No special patient preparation is required. Sample is collected from positive blood culture bottles as part of standard blood culture workflow.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance: CRP is a marker of systemic inflammation. While not specific to a single condition, it can help guide treatment decisions, track disease progression, or evaluate response to therapy. High CRP may prompt further investigation for underlying causes like infections, autoimmune diseases, or metabolic disorders.
Short name
High-sensitivity CRP
Frequently asked questions
What causes CRP levels to rise?
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