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C-reactive protein (CRP) by nephelometry

Published: August 9, 2026Updated: August 16, 2026

This test measures a protein in your blood that rises when your body is fighting inflammation or infection.

Quick summary

["Helps track inflammation, infection risk, or response to treatment for conditions like arthritis or heart disease."]

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

Key facts at a glance

LOINC
36004-0
Short code
CT Hand-Bl
Synonyms
CT Hand-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
ct
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 It’s Ordered

Your doctor may order this test to check for signs of inflammation, monitor chronic conditions like arthritis or heart disease, or evaluate risk for heart attack or stroke. High levels can also signal infections, autoimmune diseases, or other inflammatory processes.

What to Expect Before the Test

No special preparation is needed. You’ll provide a blood sample drawn from your arm. If you’re on blood thinners, let your doctor know before the test.

What the Results Mean

Results are typically reported in milligrams per liter (mg/L). Higher-than-normal levels suggest inflammation or infection, while lower levels may indicate no active inflammation. Your doctor will interpret results in the context of your health.

Common Conditions Monitored

This test is often used to monitor conditions like rheumatoid arthritis, lupus, or heart disease. It can also help assess infection risk or response to treatments like steroids or anti-inflammatory drugs.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CRP (High Sensitivity)

Frequently asked questions

What does a high CRP level mean?
A high CRP level may indicate inflammation, infection, or an autoimmune condition. Your doctor will consider your symptoms, medical history, and other test results to determine the cause.
Can diet or exercise affect CRP levels?
Yes, lifestyle factors like diet, exercise, and smoking can influence CRP levels. Eating a heart-healthy diet, staying active, and avoiding smoking may help lower CRP levels over time.
How often should I get this test?
Your doctor will determine how often you need this test based on your health needs. Regular monitoring may be part of managing chronic conditions like arthritis or heart disease.
  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