C-reactive protein, mass concentration in serum
This test measures the level of C-reactive protein (CRP) in your blood, a protein produced by the liver in response to inflammation.
["CRP helps your doctor assess inflammation in your body."]
Key facts at a glance
- LOINC
- 31157-1
- Short code
- COHgb Bld-mCnc
- Synonyms
- COHgb Bld-mCnc
- Category
- hematology
- Sample
- whole-blood
- Container
- Lavender-top (EDTA)
- Units
- N/A
- Ref low
- 12
- Ref high
- 17.5
- Critical range
- 7 N/A – 20 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 85018
- SNOMED
- 900000000000003004
- Specimen volume
- 3 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
Why Is This Test Done?
Doctors may order CRP testing to check for signs of inflammation, monitor conditions like infections, autoimmune diseases, or heart disease, or evaluate responses to treatments. It can also help identify risks for conditions like heart attacks or stroke.
What to Expect Before the Test
No special preparation is usually needed. You may be asked to fast for 8–12 hours before the test if it’s part of a fasting profile, but this isn’t always required for CRP alone. Bring any medications you’re taking to your appointment.
How the Test Is Performed
A healthcare provider will draw blood from a vein in your arm using a needle. You may feel a small pinch, but it usually doesn’t cause discomfort afterward. The blood sample is then sent to a lab for analysis.
What the Results Mean
CRP levels vary depending on your health and medical history. Higher-than-normal levels may signal inflammation, while lower levels suggest minimal inflammation. Your doctor will interpret results in the context of your overall health.
Reference range
Adult males: 13.5-17.5 g/dL; Females: 12.0-16.0 g/dLN/A
No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
CRP plays a key role in detecting and managing inflammatory conditions. Elevated CRP can indicate acute infections (like pneumonia or urinary tract infections), chronic diseases (such as rheumatoid arthritis or lupus), or cardiovascular risks. It’s also used to monitor treatment effectiveness in some cases.
Short name
CRP (Serum)
Frequently asked questions
What causes CRP levels to rise?
How long does it take to get CRP test results?
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