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C-reactive protein, serum, measured 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.

Quick summary

["CRP helps assess inflammation in your body, often used to monitor conditions like infections or autoimmune diseases."]

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

Key facts at a glance

LOINC
110994-1
Short code
C pneum IgA Msmt Ser
Synonyms
C pneum IgA 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
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 this test to check for signs of inflammation, monitor chronic conditions like arthritis or heart disease, or evaluate infections. It can also help track how well treatments are working.

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 on blood thinners, let your provider know before the test.

What the Results Mean

Higher-than-normal CRP levels may indicate inflammation, infections, or other health issues. Lower levels suggest reduced inflammation. Your provider will interpret results in the context of your medical history and symptoms.

Common Conditions Monitored

CRP is often used to monitor conditions like rheumatoid arthritis, lupus, heart disease, or infections such as pneumonia or sepsis. It can also help guide decisions about starting or stopping certain medications.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

C-reactive protein is a marker of systemic inflammation. Elevated levels may signal underlying inflammation that could affect organs, joints, or blood vessels. While CRP doesn’t diagnose specific conditions, it helps healthcare providers assess risk and guide treatment plans.

Short name

CRP (Serum)

Frequently asked questions

What causes CRP levels to be high?
CRP can rise due to infections (like a cold or flu), injuries, surgeries, or certain medical conditions such as autoimmune diseases. Stress, smoking, or certain medications may also influence CRP levels.
How often should I get this test?
Your provider will determine how often you need this test based on your health needs. Some people get it yearly, while others may need it more frequently if they have ongoing health concerns.
Can diet or lifestyle affect CRP levels?
Yes, diet, exercise, and weight management can influence CRP levels. Reducing inflammation through a balanced diet, avoiding smoking, and managing stress may help lower CRP levels over time.
  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