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C-reactive protein (CRP) concentration, plasma

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

This test measures the level of C-reactive protein in your blood plasma. CRP is a protein produced by your liver in response to inflammation or infection.

Quick summary

["CRP helps your doctor track inflammation in your body."]

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

Key facts at a glance

LOINC
101063-6
Short code
C little o3 Ab SerPl Ql
Synonyms
C little o3 Ab SerPl Ql
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 Is Done

Doctors may order a CRP test to check for signs of inflammation, monitor conditions like arthritis, heart disease, or infections, or evaluate responses to treatments. It can also help identify risks for conditions such as heart disease or autoimmune disorders.

What to Expect Before the Test

No special preparation is needed for this test. You may have a small needle inserted into your arm to draw a blood sample. If you’re on blood thinners, let your doctor know before the test.

What the Results Mean

Higher CRP levels often indicate inflammation, but they can also be influenced by factors like stress, recent illness, or certain medications. Your doctor will interpret the results in the context of your overall health and symptoms.

Common Conditions Monitored

CRP is commonly used to monitor conditions like rheumatoid arthritis, lupus, or heart disease. It can also help assess infection risks or guide decisions about treatments for inflammatory diseases.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

CRP levels can rise acutely with infections (e.g., pneumonia, urinary tract infections) or chronically with chronic inflammatory diseases. While CRP is a useful marker, it’s not definitive for diagnosing specific conditions alone. Your doctor will consider other factors, such as symptoms, medical history, and additional tests.

Short name

CRP Plasma

Frequently asked questions

What causes CRP levels to change?
CRP levels can increase due to infections (like colds or flu), injuries, surgeries, or certain medications. They may also rise with chronic conditions like arthritis or heart disease. Stress, obesity, or smoking can sometimes affect CRP levels too.
How long does it take to get results?
Results are typically available within 1–3 business days, depending on your lab’s processing time. Your doctor will contact you with the final report.
Can CRP levels be affected by diet or exercise?
Yes, lifestyle factors like diet (e.g., Mediterranean diet) and exercise can influence CRP levels. Reducing inflammation through healthy habits may help lower CRP over time, but results vary among individuals.
  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