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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 doctors assess 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
31302-3
Short code
C pneum IgG Ser-aCnc
Synonyms
C pneum IgG Ser-aCnc
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 responses to treatments. It can also help diagnose infections or identify risks for conditions like heart disease or certain cancers.

What to Expect Before the Test

No special preparation is usually needed. You may be asked to fast before the test if it’s part of a broader blood panel, but your provider will let you know. The test involves a simple blood draw from a vein in your arm.

What the Results Mean

Higher CRP levels often indicate inflammation, which can be caused by infections, injuries, or autoimmune diseases. Lower levels suggest minimal inflammation. Your results will be compared to standard reference ranges provided by your lab.

Common Conditions Monitored

CRP is commonly used to monitor conditions like rheumatoid arthritis, lupus, or heart disease. It may also be checked after surgery or trauma to track healing progress.

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 be higher than usual?
CRP levels can rise due to infections (like pneumonia or urinary tract infections), injuries, surgeries, or certain chronic conditions such as arthritis or heart disease. Stress, smoking, or certain medications may also affect CRP levels.
How soon will I get my results, and what should I do next?
Results are typically available within a few days to a week, depending on your lab. Your healthcare provider will discuss the meaning of your results and any next steps, such as additional tests or treatments.
Can diet or lifestyle changes 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, but results may take weeks to reflect changes.
  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