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C-reactive protein (CRP) concentration in 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 inflammation, guiding treatment decisions for conditions like infections, autoimmune diseases, or heart disease."]

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

Key facts at a glance

LOINC
95891-8
Short code
ICU beds occupied/ICU beds NFr
Synonyms
ICU beds occupied/ICU beds NFr
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 check for signs of inflammation, monitor chronic conditions like arthritis or heart disease, or evaluate responses to treatments. It can also help diagnose infections or assess risks for complications like heart attacks or strokes.

What to Expect Before the Test

No special preparation is needed. You may have a small needle inserted into your arm or hand to draw a blood sample. If you’re fasting, follow your provider’s instructions to ensure accurate results.

What the Results Mean

Higher-than-normal CRP levels may indicate inflammation, infections, or certain diseases. Lower levels suggest reduced inflammation. Your results will be interpreted by your healthcare provider based on your medical history and symptoms.

Common Conditions Monitored

This test is often used to monitor conditions like rheumatoid arthritis, heart disease, or infections. It can also help track how well treatments are working for inflammatory or autoimmune conditions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

CRP is a marker for inflammation, often used alongside other tests to assess risk or guide treatment. Elevated levels may prompt further evaluation for underlying causes, such as infections, autoimmune disorders, or cardiovascular risks.

Short name

CRP Plasma

Frequently asked questions

What causes CRP levels to change?
CRP levels can rise due to infections (like a cold or flu), injuries, surgeries, or certain medications. They may also be higher in people with autoimmune diseases or heart disease. Stress or recent illness can temporarily affect results.
How often should I get this test?
Your healthcare provider will determine how often you need this test based on your health needs. Some people get it yearly to monitor chronic conditions, while others may need it more frequently if symptoms change or treatment adjustments are needed.
Can I eat or drink before this test?
Typically, you can eat and drink normally unless your provider specifies otherwise. Fasting may be required for some tests, but CRP does not require fasting, so you can proceed as usual.
  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