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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 in your blood, a marker often used to check for inflammation or infection.

Quick summary

["CRP helps track inflammation, guiding decisions about treatment or further testing."]

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

Key facts at a glance

LOINC
36039-6
Short code
XR tomo Knee-Bl
Synonyms
XR tomo Knee-Bl
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
xr-tomography
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 monitor conditions like arthritis, infections, or other inflammatory diseases. It can also help assess how well you’re responding to treatment for these conditions.

What Does a High or Low CRP Level Mean?

Elevated CRP levels often indicate inflammation or infection, but they can also be raised due to other factors like stress, certain medications, or chronic conditions. Low levels usually mean little to no inflammation is present.

How Is This Test Performed?

A blood sample is drawn from a vein, typically in your arm. The sample is then analyzed in a lab using nephelometry, a method that measures how much light scatters when it interacts with proteins in the blood.

What Are Common Results?

Results are not provided with specific numeric ranges here, as they vary by lab and individual health. Your results will be interpreted by your healthcare provider based on your overall health and symptoms.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

CRP is a non-specific marker that helps identify inflammation in the body. It’s widely used in clinical settings to monitor chronic diseases like rheumatoid arthritis, cardiovascular risk, and post-surgical or post-injury healing. High CRP levels may prompt additional testing or adjustments to treatment plans.

Short name

CRP (Nephelometry)

Frequently asked questions

What causes CRP levels to change?
CRP levels can rise due to infections (like pneumonia or urinary tract infections), autoimmune diseases (like lupus or rheumatoid arthritis), injuries, or other inflammatory conditions. They may also be temporarily elevated from stress, certain medications, or recent surgery.
How long does it take to get CRP results?
Results from this test are typically available within 24 to 48 hours, depending on lab processing times. Your healthcare provider will discuss the results with you during your follow-up visit.
Can CRP levels be affected by diet or lifestyle?
Yes, diet and lifestyle factors can influence CRP levels. For example, a healthy diet rich in fruits, vegetables, and omega-3 fatty acids may help reduce inflammation. Regular exercise and avoiding smoking also tend to lower CRP levels.
  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