C-reactive protein (CRP) by nephelometry
This test measures a protein in your blood that rises when your body is responding to inflammation, infection, or injury.
["Helps detect early signs of inflammation, infections, or autoimmune conditions."]
Key facts at a glance
- LOINC
- 101125-3
- Short code
- OXA235
- Synonyms
- blaOXA-235-like gene Islt/Spm Ql
- Category
- chemistry
- Sample
- serum
- Container
- Sterile transport container or swab in appropriate transport medium (e.g., Amies or Stuart's medium) for bacterial isolates; blood culture bottles for blood specimens
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–120 years
- Method
- molgen
- CPT
- 87798
- SNOMED
- 417044008
- Specimen volume
- Variable depending on specimen type: 1-2 mL for body fluids; sufficient quantity of bacterial isolate from culture; appropriate swab for screening cultures
- Stability
- Specimens should be transported to the laboratory within 2 hours at room temperature. Bacterial isolates stable at 2-8°C for up to 24 hours. For prolonged storage, freeze at -70°C.
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–48 hours
- Order
- routine
Why It’s Ordered
Your doctor may order this test to monitor conditions like rheumatoid arthritis, heart disease, or infections. It can also check for inflammation after surgery or injury, or to evaluate symptoms like fever, joint pain, or unexplained fatigue.
What to Expect Before the Test
No special preparation is needed. You may have a small needle inserted into your arm to draw blood. If you’re on blood thinners, let your doctor know before the test.
What the Results Mean
Higher-than-normal levels may indicate inflammation, infection, or certain diseases. Lower-than-normal levels might suggest chronic inflammation or certain immune disorders. Your doctor will interpret results in the context of your health history.
Common Conditions Monitored
This test is often used to track inflammation in conditions like autoimmune diseases (e.g., lupus, rheumatoid arthritis), heart disease, infections, or after procedures like surgery or chemotherapy.
Reference range
Negative (blaOXA-235-like gene not detected)N/A
No special patient preparation required. Collect specimen prior to initiation of antimicrobial therapy when possible.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance: CRP is a marker of systemic inflammation. Elevated levels can signal acute infections (e.g., pneumonia, urinary tract infections), chronic diseases (e.g., cardiovascular disease), or inflammatory conditions (e.g., inflammatory bowel disease). It’s less specific than some other tests but useful for broad monitoring.
Short name
CRP (High-Sensitivity)
Frequently asked questions
Why might my CRP levels be higher than usual?
What if my CRP levels are normal but I still feel unwell?
Can diet or exercise 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