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C-reactive protein (CRP) concentration, serum/plasma

Published: August 9, 2026Updated: August 16, 2026

This test measures the level of C-reactive protein, a protein produced by the liver in response to inflammation in your body.

Quick summary

["CRP helps doctors assess inflammation and identify potential infections or other health issues."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
35292-2
Short code
Chr 11 UpDi Bld/T Ql
Synonyms
Chr 11 UpDi Bld/T Ql
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
cytogenetics
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 CRP Matters in Your Health

CRP is often used to monitor conditions like infections, autoimmune diseases, or after surgery to check for signs of inflammation. It can also help track how well certain treatments are working.

What Does CRP Tell Us About Your Body?

Elevated CRP levels may indicate an active infection, tissue damage, or an inflammatory condition. However, CRP alone isn’t diagnostic—it’s usually one piece of a larger picture.

How Is CRP Tested?

This test involves drawing blood from a vein in your arm. The blood is then sent to a lab where it’s analyzed using an immunoassay method to measure CRP concentration.

What Might Affect CRP Levels?

Several factors can influence CRP levels, including recent infections, injuries, stress, certain medications, or underlying health conditions like heart disease or arthritis.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: CRP’s Role in Diagnosis and Monitoring

Short name

CRP

Frequently asked questions

What could cause my CRP levels to be higher than usual?
Higher CRP levels often signal inflammation or infection, but they can also be influenced by other factors like recent illness, physical activity, or certain medications. A healthcare provider will consider your full medical history and other test results to interpret results accurately.
How soon after an infection or injury might CRP levels return to normal?
CRP levels typically rise within days of an infection or injury and may take weeks to return to normal. The timeline depends on the cause and your body’s response.
Is CRP the only test needed to diagnose an infection?
No, CRP is a useful marker but isn’t definitive on its own. Doctors often rely on clinical symptoms, physical exams, and other tests (like blood cultures or imaging) to diagnose infections or conditions.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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