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C-reactive protein (CRP) mass concentration in serum/plasma

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

This test measures the amount of C-reactive protein, a protein produced by the liver in response to inflammation in your body.

Quick summary

["CRP helps your doctor track inflammation, often used to check for infections or other inflammatory conditions."]

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

Key facts at a glance

LOINC
69800-1
Short code
MEK Fld-mCnc
Synonyms
MEK Fld-mCnc
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 Is This Test Done?

Your doctor may order a CRP test to monitor conditions like infections, autoimmune diseases (such as rheumatoid arthritis), or to check for signs of inflammation after surgery or injury. It can also help evaluate risk for heart disease or other chronic illnesses.

What to Expect Before the Test

No special preparation is needed. You may have blood drawn from a vein in your arm, similar to other blood tests. If you’re on blood thinners, let your doctor know before the test.

What the Results Mean

Higher CRP levels often indicate inflammation, but the exact meaning depends on your overall health and symptoms. Your doctor will interpret results in the context of your medical history and other tests.

Common Causes of Elevated CRP

Elevated CRP can be caused by infections (like pneumonia or urinary tract infections), injuries, surgeries, or certain medical conditions like arthritis or heart disease. It may also appear in people with no obvious illness if they have a higher risk for inflammation-related problems.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CRP (Serum/Plasma)

Frequently asked questions

How often should I get this test?
Your doctor will determine how often you need this test based on your health condition. Some people may need it monthly, while others may only need it once or twice a year.
Can diet or exercise affect CRP levels?
Yes, lifestyle factors like diet, exercise, and weight can influence CRP levels. Eating a heart-healthy diet, staying active, and maintaining a healthy weight may help lower inflammation over time.
Is there anything I should avoid before the test?
Avoid heavy meals or strenuous activity 24 hours before the test, as these can sometimes affect blood test results. If you’re on medications, let your doctor know before the 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