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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 in your blood, a protein produced by your liver in response to inflammation.

Quick summary

["CRP helps doctors assess inflammation, often used to check for infections or other inflammatory conditions."]

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

Key facts at a glance

LOINC
63404-8
Short code
ENA SS-B Ab CSF IA-aCnc
Synonyms
ENA SS-B Ab CSF IA-aCnc
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ia
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your healthcare provider may order a CRP test to monitor conditions like infections, autoimmune diseases (such as rheumatoid arthritis), or after surgery or injury to check for signs of inflammation. It can also help track how well treatments are working or if inflammation is worsening.

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 CRP levels often indicate inflammation, but the exact meaning depends on your symptoms, medical history, and other test results. Your provider will interpret the results in the context of your overall health.

Common Conditions Monitored

CRP is commonly used to monitor conditions like infections (such as pneumonia or urinary tract infections), inflammatory diseases (like lupus or inflammatory bowel disease), and to evaluate responses to treatments for these conditions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CRP (NONE)

Frequently asked questions

What causes CRP levels to be higher than usual?
CRP levels can rise due to infections (bacterial, viral, or fungal), injuries, surgeries, autoimmune diseases, or other inflammatory processes. Stress, obesity, or certain medications may also affect CRP levels.
How often should I get this test?
Your provider will determine how often you need this test based on your health condition and treatment plan. Some people get it every few months, while others may need it only occasionally.
Can diet or lifestyle changes affect CRP levels?
Yes, lifestyle factors like diet, exercise, and smoking can influence CRP levels. Reducing inflammation through healthy eating, regular activity, and avoiding smoking may help lower CRP levels over time.
  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