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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 track 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
18571-0
Short code
J Pnt ST Amp+80ms L-I
Synonyms
J Pnt ST Amp+80ms L-I
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ekg
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 rheumatoid arthritis or lupus, or evaluate symptoms such as fever, joint pain, or swelling. It can also help assess how well you’re responding to treatment for an infection or inflammatory disease.

What to Expect Before the Test

No special preparation is needed for this blood test. You may have a small needle inserted into your arm to draw a blood sample. If you’re on blood thinners, let your provider know before the test.

What the Results Mean

Higher-than-normal CRP levels often indicate inflammation, but they can also be raised due to other factors like infection, stress, or certain medications. Your results will be compared to your individual baseline or clinical context to guide decisions.

Common Conditions Monitored

CRP is commonly used to monitor conditions like infections (e.g., pneumonia, urinary tract infections), autoimmune diseases (e.g., rheumatoid arthritis, lupus), heart disease risk, and post-surgical recovery. It’s also sometimes checked after trauma or injury.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CRP (Nephelometry)

Frequently asked questions

What causes elevated CRP levels?
Elevated CRP can be caused by infections (like bacterial or viral), autoimmune diseases (such as rheumatoid arthritis or inflammatory bowel disease), heart disease, trauma, or certain medications. It’s not specific to any single condition, so results are interpreted alongside other symptoms and tests.
Can CRP levels be affected by diet or lifestyle?
Yes, diet and lifestyle can influence CRP levels. High-fat diets, obesity, smoking, and physical inactivity may increase inflammation. Small, regular physical activity and a balanced diet rich in fruits, vegetables, and omega-3s may help lower CRP levels over time.
How often should CRP be checked?
The frequency of CRP testing depends on your health condition and treatment plan. Your healthcare provider will determine how often to check it based on your symptoms, medical history, and other tests. Regular monitoring may be part of managing chronic inflammatory conditions.
  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