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C-reactive protein, serum/plasma concentration

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, often used to monitor conditions like infections, autoimmune diseases, or after surgery."]

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

Key facts at a glance

LOINC
31370-0
Short code
EBV VCA IgM CSF-aCnc
Synonyms
EBV VCA IgM CSF-aCnc
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82784
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your doctor may order a CRP test to check for signs of inflammation. This can help diagnose conditions like infections (e.g., pneumonia, urinary tract infections), autoimmune diseases (e.g., rheumatoid arthritis), or to monitor treatment progress for conditions like heart disease or certain cancers.

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 drawn from a vein (venipuncture), but fasting isn’t required for blood drawn from an arm. If your doctor specifies fasting, follow their instructions carefully.

How the Test Works

A small amount of blood is drawn from a vein in your arm. The blood is sent to a lab, where it’s analyzed to measure CRP levels using an immunoassay method, which detects the protein in your serum or plasma.

What the Results Mean

CRP levels vary depending on your health. Higher levels may indicate inflammation or infection, while lower levels suggest minimal inflammation. Your doctor will interpret the results in relation to your symptoms and medical history.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: CRP’s Role in Health

Short name

CRP (Serum/Plasma)

Frequently asked questions

Is CRP always elevated if I feel sick?
Not necessarily. CRP can rise due to infections, injuries, or autoimmune conditions, but it may also be normal even if you’re unwell if inflammation isn’t present. Your doctor will consider other factors like symptoms and lab results.
Can CRP levels change over time?
Yes, CRP levels can fluctuate. They may increase after illness, surgery, or certain medications, and can decrease with treatment or recovery. Regular monitoring helps track changes in inflammation status.
What if my CRP is very high?
A very high CRP may signal a serious infection, autoimmune disease, or other inflammatory condition. Your doctor will investigate further, possibly with additional tests or treatments to address the underlying cause.
  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