Skip to content

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 your liver in response to inflammation or infection.

Quick summary

["CRP helps track inflammation in your body, often used to monitor conditions like infections, autoimmune diseases, or heart disease."]

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

Key facts at a glance

LOINC
18561-1
Short code
J Pnt ST Amp+60ms L-III
Synonyms
J Pnt ST Amp+60ms L-III
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ekg
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 arthritis or heart disease, or evaluate responses to treatments. It can also help diagnose infections or other inflammatory conditions.

What Does a High or Low Level Mean?

Elevated CRP levels may indicate inflammation, infections, or autoimmune disorders. Lower than expected levels might suggest reduced inflammation, but this depends on your medical context and other tests.

How Is This Test Performed?

A blood sample is taken from a vein, usually in your arm. The sample is then analyzed in a lab using nephelometry, a method that measures how particles scatter light to detect protein levels.

What Are Common Conditions Monitored?

This test is commonly used to monitor conditions like rheumatoid arthritis, lupus, heart disease, infections (e.g., pneumonia), and other inflammatory or autoimmune disorders.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

CRP is a sensitive marker for inflammation and is often used alongside other tests to guide treatment decisions. It can help identify early signs of inflammation or infection, but it is not definitive on its own.

Short name

CRP (Nephelometry)

Frequently asked questions

What could cause my CRP levels to be higher than usual?
Higher CRP levels can be caused by infections (like colds or flu), injuries, surgeries, certain medications, or underlying inflammatory or autoimmune conditions. Stress or recent illness may also temporarily raise CRP levels.
How soon will I know my results?
Results are typically available within 24 to 48 hours, depending on your lab’s processing schedule. Your healthcare provider will discuss the results with you during your follow-up visit.
Can I do anything to lower my CRP levels?
While you can’t directly lower CRP levels, managing conditions like infections, heart disease, or autoimmune disorders with treatment can help reduce inflammation. Lifestyle changes such as exercise, a balanced diet, and stress management may also support overall health and reduce 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