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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, autoimmune diseases, or heart disease."]

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

Key facts at a glance

LOINC
88274-6
Short code
S anginosus gryB Bld Pos Ql Probe
Synonyms
S anginosus gryB Bld Pos Ql Probe
Category
coagulation
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
probe
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your healthcare provider may order a CRP test to check for signs of inflammation. This could be due to suspected infections, autoimmune conditions (like rheumatoid arthritis), or to monitor chronic diseases such as heart disease or kidney problems. It may also be used before or after surgery to track healing progress.

What Does a High or Low CRP Level Mean?

A higher CRP level often indicates inflammation or infection. While it doesn’t pinpoint the exact cause, it can guide treatment decisions. A consistently low CRP level may suggest no active inflammation, but it’s not definitive on its own.

How Is the Test Performed?

A blood sample is taken from a vein, usually 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 the CRP protein in the sample.

What Are Common Uses?

CRP is commonly used to screen for or monitor conditions like infections (e.g., pneumonia, urinary tract infections), inflammatory diseases (e.g., lupus, inflammatory bowel disease), and to evaluate heart health before or after a heart attack.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: CRP is a non-specific marker of inflammation. Elevated levels can signal acute or chronic inflammatory processes, but they don’t identify the underlying cause. It’s often used alongside other tests to provide a clearer picture of your health status, especially in diagnosing or managing conditions like cardiovascular disease, infections, or autoimmune disorders.

Short name

CRP (Nephelometry)

Frequently asked questions

What does a CRP test tell me about my health?
A CRP test helps your healthcare provider determine if there’s inflammation in your body, which can be linked to infections, injuries, or certain diseases. It doesn’t tell you the exact cause but can guide further testing or treatment plans.
How often should I get a CRP test?
The frequency depends on your medical condition and your doctor’s recommendations. Some people get it yearly for monitoring, while others may need it more often if they have ongoing health issues like heart disease or autoimmune disorders.
Can I eat or drink before the test?
You can usually eat and drink normally before the test unless your doctor specifies otherwise. However, some tests may require fasting; always follow your healthcare provider’s instructions.
  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