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C-reactive protein (CRP) in plasma

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

This test measures the level of C-reactive protein, a protein produced by your liver in response to inflammation in the body.

Quick summary

["CRP helps identify inflammation that may be causing symptoms or underlying conditions."]

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

Key facts at a glance

LOINC
101942-1
Short code
C lusitaniae DNA Spec Ql NAA+probe
Synonyms
C lusitaniae DNA Spec Ql NAA+probe
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
probe-amp-tar
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. CRP levels can also help assess risk for future health issues, such as heart problems.

What Does a High CRP Level Indicate?

Elevated CRP levels often signal inflammation, which can be caused by infections (like pneumonia or urinary tract infections), injuries, or conditions like rheumatoid arthritis or lupus. High CRP may also indicate an increased risk of heart disease or other chronic inflammatory diseases.

What Does a Low CRP Level Indicate?

Low CRP levels generally suggest minimal inflammation. However, very low levels might raise concerns if inflammation is expected, so results should always be interpreted by a healthcare provider in the context of your overall health.

How Is This Test Performed?

A small blood sample is drawn from a vein in your arm. The blood is then processed to separate plasma, which is analyzed for CRP levels using a sensitive immunoassay method.

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 plasma, a protein that rises when your body is inflamed or fighting infection.
How long does it take to get CRP test results?
Results are typically available within 1 to 3 business days, depending on your lab and healthcare provider’s processes.
Can CRP levels change with diet or exercise?
While diet and exercise can influence overall inflammation, CRP levels are primarily responsive to acute inflammation or underlying health conditions. Your provider will consider lifestyle factors alongside test results when assessing your health.
  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