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C-reactive protein (CRP) by immunoassay (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.

Quick summary

["CRP helps identify inflammation, often used to monitor conditions like infections, autoimmune diseases, or after surgery."]

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

Key facts at a glance

LOINC
4996-5
Short code
CMV DNA Bld Ql NAA+probe
Synonyms
CMV DNA Bld Ql NAA+probe
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
probe-amp-tar
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your healthcare provider may order a CRP test to check for signs of inflammation, monitor chronic conditions like arthritis or heart disease, or evaluate responses to treatments. It can also help diagnose infections or assess risk for conditions like heart disease.

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 CRP levels often indicate inflammation, but results depend on your health history and symptoms. Elevated levels may signal infections, autoimmune diseases, or other inflammatory conditions.

Common Conditions Monitored

CRP is used to track conditions like rheumatoid arthritis, lupus, or heart disease. It may also help guide decisions about treatments or infections.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CRP (Serum/Plasma)

Frequently asked questions

What causes CRP levels to change?
CRP levels rise in response to infections, injuries, or inflammatory diseases. Stress, certain medications, or recent procedures can also temporarily affect results. Smoking or obesity may influence baseline levels.
How long does it take to get results?
Results are typically available within 24 to 48 hours, depending on lab processing times. Your provider will discuss them with you during your follow-up visit.
Can diet or exercise affect CRP levels?
Yes, lifestyle factors like diet, exercise, and weight can influence CRP levels. Reducing inflammation through healthy habits may lower CRP over time, but results depend on overall health and medical conditions.
  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