Skip to content

C-reactive protein (CRP) by nephelometry (serum/plasma)

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
96484-1
Short code
NIF-H IgG Ser Ql CBA IFA
Synonyms
NIF-H IgG Ser Ql CBA IFA
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
cba-ifa
CPT
82784
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 a CRP test to check for signs of inflammation, monitor chronic conditions like rheumatoid arthritis or lupus, or evaluate responses to treatments. It can also help diagnose infections, such as pneumonia or appendicitis, or assess risks for heart disease.

How Is the Test Performed?

A small blood sample is drawn from a vein in your arm. The blood is sent to a lab where it is analyzed using nephelometry, a method that measures how particles scatter light to detect protein levels.

What Do the Results Mean?

Results are typically reported in milligrams per liter (mg/L). Higher than usual levels may indicate inflammation, infection, or other health issues. Your provider will interpret results in the context of your overall health and symptoms.

Common Conditions Monitored

CRP is often used to monitor conditions like infections, autoimmune diseases (e.g., rheumatoid arthritis), or to check for signs of inflammation after procedures or injuries.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CRP (Serum/Plasma)

Frequently asked questions

What causes CRP levels to be high?
CRP levels can rise due to infections (like colds, flu, or urinary tract infections), injuries, surgeries, or certain medical conditions such as autoimmune diseases (e.g., rheumatoid arthritis). Stress, smoking, or certain medications may also influence CRP levels.
How often should I get a CRP test?
The frequency depends on your medical needs. Your healthcare provider will determine how often to check CRP based on your symptoms, diagnosis, or treatment plan. Regular monitoring may be recommended for chronic conditions.
Can CRP levels be affected by diet or lifestyle?
Yes, certain foods, smoking, exercise, and stress can influence CRP levels. While diet changes alone won’t lower CRP, maintaining a healthy lifestyle—such as eating anti-inflammatory foods, avoiding smoking, and managing stress—may help support overall health and reduce inflammation.
  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