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C-reactive protein (CRP) concentration, plasma

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

This test measures the level of C-reactive protein in your blood plasma, a marker often checked for signs of inflammation or infection.

Quick summary

["CRP helps doctors assess inflammation, which may signal conditions like infections, autoimmune diseases, or other health issues."]

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

Key facts at a glance

LOINC
12227-5
Short code
WBC nRBC cor # Bld
Synonyms
WBC nRBC cor # Bld
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Ref low
4.5
Ref high
11
Critical range
2 N/A – 30 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
85004
SNOMED
900000000000003002
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 This Test Is Done

Doctors may order a CRP test to monitor conditions like arthritis, heart disease, or infections. It can also help track how well treatment is working or check for hidden inflammation in your body.

What to Expect Before the Test

You’ll typically have a small needle inserted into your arm to draw blood. No special preparation is needed, but inform your doctor about any medications or recent illnesses.

What the Results Mean

Higher CRP levels often mean inflammation is present, but the exact meaning depends on your overall health and symptoms. Your doctor will interpret results in the context of your medical history.

Common Conditions Monitored

CRP is used to evaluate conditions like rheumatoid arthritis, heart attack risk, infections (e.g., pneumonia), and other inflammatory diseases.

Reference range

Adult: 4.5-11.0 x 10^9/LN/A

Specimen: whole-blood

No special preparation required. Stay well hydrated.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: CRP’s Role in Healthcare

Short name

CRP (Plasma)

Frequently asked questions

How long does it take to get CRP test results?
Results are usually available within 1–3 business days, depending on your lab. Follow-up with your doctor to discuss findings.
Can diet affect CRP levels?
Yes, diet can influence CRP. Reducing processed foods, sugars, and unhealthy fats while eating more fruits, vegetables, and omega-3s may lower inflammation.
Is CRP always elevated in infections?
Not always. CRP rises in infections, but it can also be elevated due to other causes like autoimmune diseases or chronic conditions. Your doctor will guide interpretation.
  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