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C-reactive protein (CRP) by nephelometry

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
23269-4
Short code
M cap caprip Ag Spec Ql
Synonyms
M cap caprip Ag Spec Ql
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 chronic conditions like rheumatoid arthritis or lupus, or evaluate symptoms such as fever, joint pain, or swelling. It can also be used to monitor treatment effectiveness or detect infections.

What Does a High CRP Level Mean?

Elevated CRP levels often indicate inflammation or infection. While it doesn’t specify the cause, high levels may signal conditions like infections (e.g., pneumonia), autoimmune diseases, or other inflammatory processes.

What Does a Low CRP Level Mean?

Low CRP levels usually mean there is little to no inflammation in your body. However, very low levels might also be seen in people with certain genetic conditions or those on specific medications that suppress inflammation.

Common Conditions Monitored with CRP

This test is commonly used to monitor conditions such as cardiovascular disease risk, infections, and inflammatory diseases like arthritis or inflammatory bowel disease. It can also help guide decisions about starting or adjusting medications.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

CRP is a marker for inflammation and can be elevated in response to infections, injuries, or autoimmune disorders. While it doesn’t diagnose a specific condition, it helps healthcare providers assess overall inflammation levels and tailor treatment plans accordingly.

Short name

CRP (Nephelometry)

Frequently asked questions

What does a CRP test measure?
A CRP test measures the amount of C-reactive protein in your blood, which is produced by your liver in response to inflammation. This protein is a general indicator of inflammation, not a specific disease.
How long does it take to get CRP test results?
Results from a CRP test are typically available within a few days to a week, depending on your lab’s processing times. Your healthcare provider will discuss the results with you during your follow-up visit.
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 levels, but this depends on the underlying cause of your inflammation.
  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