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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 that rises in response to inflammation or infection.

Quick summary

["CRP helps doctors track inflammation and identify possible infections or conditions causing swelling."]

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

Key facts at a glance

LOINC
110786-1
Short code
C pneum Ab Msmt Ser
Synonyms
C pneum Ab Msmt Ser
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 doctor may order this test to check for inflammation, monitor chronic conditions like arthritis or heart disease, or evaluate symptoms such as fever, pain, or swelling that might suggest an infection or autoimmune disorder.

What to Expect Before the Test

No special preparation is needed. You may have a small needle inserted into your arm to draw blood, which usually causes only minor discomfort. Avoid heavy exercise or eating a large meal before the test to ensure accurate results.

What the Results Mean

Higher-than-normal CRP levels often indicate inflammation, infection, or other health issues. Lower levels may suggest no active inflammation. Your doctor will interpret results in the context of your overall health and symptoms.

Common Conditions Monitored

CRP is commonly used to monitor conditions like rheumatoid arthritis, heart disease, infections (e.g., pneumonia, urinary tract infections), and inflammatory bowel disease. It can also help assess how well treatments are working.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical significance: CRP is a sensitive marker of inflammation. Elevated levels can signal infections, autoimmune diseases, or tissue damage, guiding treatment decisions. However, it’s not specific to any single condition and should be interpreted alongside other clinical findings.

Short name

CRP (Neph)

Frequently asked questions

What causes CRP levels to change?
CRP levels can rise due to infections (like colds or flu), injuries, surgeries, or certain medications. They may also be higher in people with chronic conditions like arthritis or heart disease. Stress, smoking, or obesity can sometimes influence CRP levels too.
How often should I get this test?
Your doctor will determine how often you need this test based on your health condition and symptoms. Some people get it yearly to monitor long-term inflammation, while others may need it more often if they have an ongoing illness or treatment.
Can diet or lifestyle affect CRP levels?
Yes, diet and lifestyle can impact CRP levels. Eating a heart-healthy diet, staying active, and managing stress may help lower inflammation. Avoiding smoking and limiting processed foods can also support healthier CRP levels.
  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