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C-reactive protein (CRP) 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 doctors assess inflammation, often used to monitor conditions like infections or autoimmune diseases."]

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

Key facts at a glance

LOINC
9520-8
Short code
ECV9 Ab Titr CSF CF
Synonyms
ECV9 Ab Titr CSF CF
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
comp-fix
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 healthcare provider may order this test to check for signs of inflammation, monitor chronic conditions like arthritis or heart disease, or evaluate symptoms such as fever, pain, or swelling that may indicate infection or an immune response.

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 involves drawing blood, but this is not always required for CRP. Always follow your provider’s instructions.

During the Test

A healthcare professional will insert a needle into a vein in your arm to draw a small amount of blood. You may feel a brief pinch, but it usually doesn’t cause significant discomfort. The process takes a few minutes.

After the Test

You can resume normal activities immediately. Apply gentle pressure to the site to stop any bleeding, and avoid rubbing it. Check with your provider if you experience excessive bruising or pain.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Elevated CRP levels often signal inflammation, which can be caused by infections, injuries, or autoimmune diseases. While CRP doesn’t identify the exact cause, it helps guide treatment decisions, such as adjusting medications or starting antibiotics. Low or normal levels may indicate no active inflammation, but further evaluation is needed if symptoms persist.

Short name

CRP (Serum/Plasma)

Frequently asked questions

How long does it take to get my results?
Results are typically available within 1–3 business days, depending on your lab’s processing time. Your healthcare provider will discuss the results with you during your follow-up visit.
Can I eat or drink before this test?
Most CRP tests do not require fasting, but always confirm with your provider. If fasting is advised, avoid food and liquids (except water) for 8–12 hours before the blood draw.
What does a high CRP level mean?
A high CRP level suggests inflammation is present. It doesn’t pinpoint the cause, but it may indicate infections, autoimmune disorders, or other inflammatory conditions. Your provider will interpret results in the context of your symptoms and medical history.
  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