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

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. It helps doctors assess whether you have an ongoing inflammatory condition or infection.

Quick summary

["CRP helps track inflammation and guide treatment decisions."]

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

Key facts at a glance

LOINC
69961-1
Short code
HEV RNA SerPl NAA+probe-aCnc
Synonyms
HEV RNA SerPl NAA+probe-aCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
probe-amp-tar
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 a marker of inflammation, meaning it rises when your body is fighting infection, healing from injury, or dealing with autoimmune diseases. High levels may signal conditions like arthritis, heart disease, or infections.

How the Test Works

Your blood sample is analyzed using nephelometry, a method that detects CRP particles in your serum or plasma. The test measures how much CRP is present, helping your healthcare provider compare it to your baseline or symptoms.

Common Uses for CRP Testing

Doctors often use CRP to monitor chronic conditions like rheumatoid arthritis or inflammatory bowel disease. It may also be checked after surgery, trauma, or during pregnancy to detect hidden inflammation.

What to Expect Before the Test

No special preparation is needed, but avoid strenuous activity or certain medications (like NSAIDs) for 24 hours before testing, as they can affect inflammation levels.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

CRP is critical for diagnosing and managing conditions like sepsis, heart disease, or autoimmune disorders. It helps doctors adjust treatments, such as steroids or biologics, to reduce inflammation safely.

Short name

CRP (Nephelometry)

Frequently asked questions

Will CRP levels change if I’m sick?
Yes, CRP levels often rise during infections (like flu or UTIs) or illnesses like COVID-19. They may also spike after surgery or injury, but they return to normal as your body heals.
What does a high CRP mean?
A high CRP suggests inflammation, but it doesn’t always point to a specific cause. Your doctor will consider symptoms, other tests, and medical history to determine if treatment is needed.
Can CRP levels be affected by diet?
Dietary factors like omega-3 fatty acids (found in fish) or anti-inflammatory foods may lower CRP, but they don’t replace medical treatment. Always follow your doctor’s advice.
  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