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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 identify 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
22675-3
Short code
Deprecated ACE SerPl-cCnc
Synonyms
Deprecated ACE SerPl-cCnc
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 arthritis or heart disease, or evaluate responses to treatments. It can also help diagnose infections or assess risks for conditions like heart disease.

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 instructed, but this depends on your lab’s protocol. Bring any medications you’re taking to your appointment.

What Happens During the Test?

A blood sample is drawn from a vein in your arm. The blood is sent to a lab where it is analyzed using nephelometry, a method that measures how much light is scattered by proteins in the sample.

What Are Possible Results?

Results are reported in milligrams per deciliter (mg/dL). Higher levels may indicate inflammation, infections, or other health issues. Your provider will interpret the results in the context of your overall health and symptoms.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

CRP (Nephelometry)

Frequently asked questions

What Does This Test Tell Us About My Health?
Elevated CRP levels often signal inflammation, which can be linked to infections, autoimmune diseases, or other inflammatory conditions. It’s a general marker and not specific to any single condition, so results should be reviewed with your healthcare provider.
How Often Should I Get This Test?
The frequency depends on your medical needs. Some people get it yearly to monitor chronic conditions, while others may need it more often if they have active symptoms or ongoing health concerns.
Can I Avoid This Test?
While you can’t avoid the test itself, you can discuss alternatives with your provider if you have concerns. Some conditions may be monitored differently, and your provider can tailor recommendations to your situation.
  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