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C-reactive protein (mass concentration) in 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 identify and monitor inflammation, often used to check for infections or other inflammatory conditions."]

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

Key facts at a glance

LOINC
2269-9
Short code
Comp Fact B SerPl-mCnc
Synonyms
Comp Fact B SerPl-mCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your healthcare provider may order this test to evaluate signs of inflammation, monitor chronic conditions like rheumatoid arthritis or lupus, or check for infections such as pneumonia or sepsis. It can also be used to assess how well treatments are working for inflammatory diseases.

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 a blood draw, but this depends on your provider’s instructions. Avoid strenuous activity or excessive exercise 24 hours before the test.

What Happens During the Test?

A healthcare professional will draw blood from a vein in your arm. You may feel a slight pinch or sting, but it usually doesn’t cause significant discomfort. The blood sample is then sent to a lab for analysis.

What the Results Mean

CRP levels vary depending on your health. Higher-than-normal levels may suggest inflammation, infections, or other medical issues, while lower levels may indicate no active inflammation. Your results will be discussed with your provider to guide further action.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CRP (Serum/Plasma)

Frequently asked questions

How often should I get this test?
Your provider will determine how often you need this test based on your medical history, symptoms, and treatment plan. Some people may get it monthly, quarterly, or annually depending on their condition.
Can diet or exercise affect CRP levels?
Yes, lifestyle factors like diet, exercise, and stress can influence CRP levels. Eating a balanced diet rich in fruits, vegetables, and omega-3 fatty acids, along with regular physical activity, may help lower inflammation.
What if my CRP levels are high?
If your CRP levels are elevated, your provider may recommend further testing or adjustments to your treatment plan. This could include treating an infection, managing chronic conditions, or exploring lifestyle changes to reduce inflammation.
  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