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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 protein produced by your liver in response to inflammation.

Quick summary

CRP helps identify and monitor inflammation in your body.

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

Key facts at a glance

LOINC
92966-1
Short code
M catarrhalis DNA BAL NAA+non-prb-NCncRng
Synonyms
M catarrhalis DNA BAL NAA+non-prb-NCncRng
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
non-probe-amp-tar
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

What Is C-Reactive Protein?

C-reactive protein (CRP) is a marker produced by your liver when your body is fighting infection or inflammation. Elevated levels can signal conditions like infections, autoimmune diseases, or other inflammatory processes. This test is often used to assess general inflammation or to monitor chronic conditions such as heart disease or arthritis.

Why Might You Need This Test?

Your healthcare provider may order a CRP test to check for signs of inflammation, evaluate symptoms like fever, joint pain, or swelling, or monitor treatments for conditions like rheumatoid arthritis, heart disease, or infections. It can also help determine if you have an acute infection or if inflammation is worsening over time.

What to Expect During the Test

This test typically involves drawing blood from a vein in your arm. The blood sample is sent to a lab where it is analyzed using nephelometry, a method that measures the amount of CRP in your blood. The results are usually available within a few days.

What Do the Results Mean?

Results are interpreted based on your clinical situation and symptoms. Higher-than-normal levels may indicate inflammation, infection, or other health issues. Your healthcare provider will discuss the results with you and determine if further action is needed.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

CRP (Nephelometry)

Frequently asked questions

How often will I need this test?
The frequency of CRP testing depends on your medical condition and treatment plan. Your healthcare provider will let you know how often you need the test, whether it’s part of routine check-ups, or if it’s triggered by specific symptoms or medical events.
What are the normal ranges for CRP?
There are no strict universal reference ranges for CRP. Levels can vary based on age, health status, and other factors. Your healthcare provider will use your specific results in the context of your overall health to guide their assessment.
Can lifestyle changes affect CRP levels?
Yes, lifestyle factors such as diet, exercise, smoking, and stress can influence CRP levels. Reducing inflammation through healthy habits, like eating a balanced diet, staying active, and avoiding smoking, may help 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