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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 protein produced by your liver in response to inflammation.

Quick summary

["CRP helps identify inflammation, guiding treatment decisions."]

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

Key facts at a glance

LOINC
5882-6
Short code
VZV Ag Spec Ql IF
Synonyms
VZV Ag Spec Ql IF
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
if
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 conditions like infections, autoimmune diseases, or heart disease, or evaluate responses to treatments. It can also help assess risk for certain health issues over time.

What Does a High or Low CRP Level Mean?

Elevated CRP levels often signal inflammation, which may be linked to infections, injuries, or conditions like arthritis or heart disease. Very low levels might suggest no active inflammation, but they can also occur in certain health conditions or with certain medications.

How Is the Test Performed?

A blood sample is drawn from a vein, usually in your arm. The plasma is then tested for CRP using a sensitive immunoassay method to detect its presence.

What Are Common Uses?

Common reasons include monitoring chronic diseases, assessing risk for cardiovascular events, evaluating treatment effectiveness, or screening for conditions like rheumatoid arthritis.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CRP Plasma

Frequently asked questions

What does a CRP test measure?
A CRP test measures the concentration of C-reactive protein in your blood plasma, which rises when your body is inflamed or responding to infection.
Can CRP levels change with diet or exercise?
Yes, lifestyle factors like diet, exercise, and smoking can influence CRP levels. Reducing inflammation through healthy habits may lower CRP, but results vary by individual.
Is CRP the same as a complete blood count (CBC)?
No, CRP is a specific protein test for inflammation, while a CBC checks overall blood cell counts and health, including red blood cells, white blood cells, and platelets.
  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