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C-reactive protein (CRP) by nephelometry (serum/plasma)

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 after surgery."]

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

Key facts at a glance

LOINC
111341-4
Short code
EBV VCA IgM Msmt Ser
Synonyms
EBV VCA IgM Msmt Ser
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82784
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 your response to treatment for infections or injuries. It can also be used to screen for certain conditions or guide decisions about medications.

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 it’s part of a metabolic or liver panel, but this isn’t always required for CRP alone. Bring any medications you’re taking to your appointment.

What Happens During the Test?

A small needle will be used to draw blood from a vein in your arm. The blood sample is then sent to a lab for analysis using nephelometry, a method that measures how much light scatters when CRP binds to antibodies.

What Are Possible Results?

Results are reported in milligrams per deciliter (mg/dL). Higher levels may indicate inflammation, infection, or other health issues, while lower levels suggest minimal inflammation. Your doctor will interpret results in the context of your overall health and medical history.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Elevated CRP levels can signal acute inflammation (e.g., infections, injuries) or chronic conditions like rheumatoid arthritis, cardiovascular disease, or certain cancers. It’s often used as a screening tool or to monitor disease activity. However, CRP alone isn’t diagnostic for most conditions—it’s typically one piece of a larger picture.

Short name

CRP (Nephelometry)

Frequently asked questions

What does a high CRP level mean?
A high CRP level suggests your body is actively producing inflammation. This could be due to infections (like pneumonia or urinary tract infections), autoimmune diseases (like lupus or rheumatoid arthritis), heart disease, or other inflammatory processes. Your doctor will discuss possible causes and next steps with you.
Can CRP levels change with diet or exercise?
Yes, lifestyle factors like diet, exercise, and smoking can influence CRP levels. For example, a healthy diet rich in fruits, vegetables, and omega-3 fatty acids may help lower CRP. Regular physical activity and avoiding smoking can also support lower inflammation levels.
How often should I get this test?
Your doctor will determine how often you need CRP testing based on your medical condition. Some people get it yearly as a general health check, while others may need it more frequently if they have chronic conditions like heart disease or arthritis. Follow your provider’s recommendations.
  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