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C-reactive protein (CRP) concentration 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.

Quick summary

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

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

Key facts at a glance

LOINC
74421-9
Short code
MuV IgM Fld IA-aCnc
Synonyms
MuV IgM Fld IA-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
ia
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 a CRP test to check for signs of inflammation, monitor chronic conditions like rheumatoid arthritis or lupus, evaluate infections, or assess how well you’re healing after surgery or injury.

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 signal inflammation, but results depend on your overall health and medical history. Elevated levels may prompt further testing or treatment adjustments.

Common Conditions Monitored

CRP is commonly used to track conditions like infections (e.g., pneumonia), autoimmune diseases (e.g., rheumatoid arthritis), or to evaluate response to treatments for chronic inflammation.

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 can increase due to infections (like a cold or flu), injuries, surgeries, or certain chronic conditions such as arthritis or heart disease. Stress, smoking, or certain medications may also affect CRP levels.
How long does it take to get results?
Results are typically available within 1 to 3 business days, depending on your lab’s processing time. Your provider will discuss the results with you during your follow-up visit.
Can I eat or drink before this test?
You can eat and drink normally before this test, as no fasting is required. However, always follow your healthcare provider’s specific instructions for your blood test.
  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