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

Quick summary

["CRP helps doctors assess inflammation, infection, or risk of future health issues like heart disease."]

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

Key facts at a glance

LOINC
12271-3
Short code
VZV Ab Ser Ql LA
Synonyms
VZV Ab Ser Ql LA
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
la
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 CRP Matters in Your Health

CRP is often checked when you have symptoms like fever, pain, or swelling, or if your doctor suspects an infection, autoimmune condition, or heart disease. It can also be used to monitor chronic conditions like arthritis or heart disease over time.

How the Test Works

Blood is drawn and analyzed using nephelometry, a method that measures how much light is scattered by particles in the sample, indicating CRP levels.

What to Expect Before the Test

No special preparation is needed, but inform your doctor about any medications, recent infections, or conditions that might affect results.

Possible Results and Next Steps

Higher-than-normal CRP levels may signal inflammation, infection, or other health concerns. Your doctor will discuss results in the context of your symptoms and medical history.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: CRP’s Role in Diagnosis and Monitoring

Short name

CRP (Nephelometry)

Frequently asked questions

What does a high CRP level mean?
A high CRP level often indicates inflammation, infection, or an autoimmune condition. It can help guide treatment decisions, such as starting antibiotics for an infection or adjusting medications for conditions like rheumatoid arthritis.
Can CRP levels change over time?
Yes, CRP levels can fluctuate based on activity, illness, or response to treatment. Regular monitoring may be needed for chronic conditions to track progression or effectiveness of treatment.
Is CRP the same as a complete blood count (CBC)?
No, CRP is a specific protein marker for inflammation, while a CBC checks for red and white blood cells, platelets, and other blood components.
  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