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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 your liver in response to inflammation in the body.

Quick summary

["CRP helps identify and monitor inflammation, often used to track conditions like infections or autoimmune diseases."]

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

Key facts at a glance

LOINC
45009-8
Short code
C trach Ab Ser Ql IF
Synonyms
C trach Ab Ser Ql IF
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
if
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, diagnose conditions like infections (e.g., pneumonia, urinary tract infections), or monitor diseases such as rheumatoid arthritis, lupus, or heart disease. It can also help assess how well treatments are working.

What to Expect Before the Test

No special preparation is needed for this test. You may have a small needle inserted into a vein in your arm, and a small amount of blood will be drawn. If you’re concerned about discomfort, let your provider know.

What the Results Mean

CRP levels can vary based on health, activity level, and other factors. Higher than normal levels often indicate inflammation, but they can also be influenced by stress, recent illness, or certain medications. Your provider will discuss your results in the context of your overall health.

Common Conditions Monitored

CRP is commonly used to monitor conditions like infections, autoimmune diseases (e.g., rheumatoid arthritis), and cardiovascular risks. It may also help guide decisions about treatments or further testing.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CRP

Frequently asked questions

How often should I get this test?
The frequency depends on your medical condition and treatment plan. Your healthcare provider will determine how often to check your CRP levels, such as every few months for chronic conditions or after certain treatments.
Can diet or exercise affect CRP levels?
Yes, lifestyle factors like diet, exercise, and stress can influence CRP levels. Eating a balanced diet, staying active, and managing stress may help lower inflammation over time.
What if my CRP level is high?
A high CRP level may signal inflammation, but it doesn’t always mean a specific condition. Your provider will review your results with your symptoms and other tests to determine the next steps, such as further evaluation or treatment adjustments.
  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