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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 doctors identify and monitor inflammation, often used to check for infections, autoimmune conditions, or other health concerns."]

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

Key facts at a glance

LOINC
23283-5
Short code
M myc my lc Ab Ser Ql CF
Synonyms
M myc my lc Ab Ser Ql CF
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
comp-fix
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 evaluate signs of inflammation, assess infection risk, monitor chronic conditions like arthritis or heart disease, or check for hidden inflammation that isn’t causing obvious symptoms.

What to Expect Before the Test

No special preparation is needed. You may have a small needle inserted into your arm to draw blood. If you’re concerned about needles, let your provider know. Avoid strenuous activity or excessive stress 24 hours before testing, as these can sometimes affect results.

What the Results Mean

CRP levels vary depending on health status. Higher than normal levels often indicate inflammation, but they can also be influenced by factors like recent illness, infection, or certain medications. Your provider will discuss results in the context of your overall health.

Common Conditions Monitored

CRP is commonly used to monitor conditions like rheumatoid arthritis, heart disease, or infections. It may also help track response to treatments or identify early signs of inflammation in conditions like lupus or inflammatory bowel disease.

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 levels are often caused by infections (like pneumonia or urinary tract infections), autoimmune diseases (such as rheumatoid arthritis), injuries, or other inflammatory processes. Stress, smoking, or certain medications can also temporarily raise CRP.
How often should CRP be checked?
The frequency depends on your health needs. Some people get CRP checked yearly or more often if they have chronic conditions like heart disease or arthritis. Your provider will determine the best schedule for you.
Can CRP levels be affected by diet or lifestyle?
Yes, diet and lifestyle can influence CRP levels. Reducing inflammation through a balanced diet, regular exercise, and avoiding smoking may help lower CRP. However, CRP is primarily a marker of inflammation, not a direct measure of diet quality.
  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