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C-reactive protein (CRP) by nephelometry (serum/plasma)

Published: August 9, 2026Updated: August 16, 2026

This test measures a protein produced by your liver in response to inflammation, infection, or injury. It helps doctors track low-grade inflammation or monitor conditions like autoimmune diseases.

Quick summary

["CRP helps detect and monitor subtle inflammation in your body."]

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

Key facts at a glance

LOINC
110992-5
Short code
C trach IgA Msmt Ser
Synonyms
C trach 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 This Test Might Be Ordered

Your healthcare provider may order this test to check for signs of inflammation, especially if you have symptoms like fever, fatigue, or unexplained swelling. It’s also used to monitor chronic conditions like rheumatoid arthritis, heart disease, or certain infections. In some cases, it may be part of a routine checkup to assess overall health or response to treatment.

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. Avoid strenuous activity or eating/drinking for 8–12 hours before if instructed.

What the Results Mean

Results are interpreted by your doctor based on your health history and symptoms. High levels may indicate inflammation, infection, or other health issues, while low levels may suggest no active inflammation. Your provider will discuss what your specific result means for you.

Common Conditions Monitored

This test is often used to monitor conditions like autoimmune diseases (e.g., lupus, rheumatoid arthritis), heart disease, infections, or to check for signs of inflammation after surgery or injury.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CRP (High Sensitivity)

Frequently asked questions

What does a high CRP level mean?
A high CRP level often signals inflammation, infection, or an immune response. Your doctor will consider your symptoms, medical history, and other test results to determine the cause. Common triggers include infections (like pneumonia or urinary tract infections), autoimmune diseases, or inflammatory conditions.
Can I lower my CRP level naturally?
Yes! Lifestyle changes like regular exercise, a balanced diet (rich in fruits, vegetables, and omega-3s), managing stress, and avoiding smoking can help reduce inflammation. If you have a chronic condition, follow your doctor’s advice for medications or treatments that may also lower CRP.
How often should I get this test?
Your doctor will determine how often you need this test based on your health needs. For example, people with autoimmune diseases may get it monthly or more often, while others might have it once a year or less. Follow-up schedules depend on your specific condition and treatment plan.
  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