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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, a marker often checked to assess inflammation or infection.

Quick summary

["CRP helps doctors track inflammation, infection risk, or response to treatment."]

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

Key facts at a glance

LOINC
27815-0
Short code
Fact XIII Act/Nor PPP Chro
Synonyms
Fact XIII Act/Nor PPP Chro
Category
chemistry
Sample
plasma
Container
Lavender-top (EDTA) or Green-top (Heparin)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
chromo
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 monitor conditions like infections (e.g., pneumonia, urinary tract infections), inflammatory diseases (e.g., rheumatoid arthritis, lupus), or to check for signs of heart disease or other systemic issues. It can also help evaluate how your body responds to treatments for these conditions.

What to Expect Before the Test

No special preparation is usually needed. You may have a small needle inserted into a vein (typically in your arm) to draw blood. If you’re on blood thinners, let your provider know before the test.

What the Results Mean

Higher-than-normal CRP levels often indicate inflammation or infection, but results alone don’t diagnose a condition. Your provider will consider your symptoms, medical history, and other test results to interpret the meaning.

Common Conditions Monitored

Elevated CRP is commonly seen in infections, autoimmune diseases, or after injuries/surgeries. Low or normal levels may suggest no active inflammation, but they don’t rule out all causes.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: CRP is a sensitive but nonspecific marker. While it can signal inflammation, it doesn’t replace other diagnostic tools. High levels may prompt further testing (e.g., cultures, imaging) to identify the cause. Chronic elevations could warrant follow-up to assess underlying conditions like chronic inflammation or metabolic disorders.

Short name

CRP (Plasma)

Frequently asked questions

What does a high CRP level mean?
A high CRP level suggests inflammation or infection, but it doesn’t pinpoint the exact cause. It may guide your provider to investigate further, such as checking for infections, autoimmune activity, or other health concerns.
Can CRP levels change with diet or exercise?
Yes, lifestyle factors like diet, exercise, and stress can influence CRP levels. Reducing inflammation through healthy habits may lower CRP, but results depend on overall health and medical conditions.
Is CRP tested only in plasma, or can it be done on other specimens?
CRP is most commonly tested in plasma or serum, but it can also be measured in urine or other fluids in some cases. Always confirm with your provider which specimen was used for your 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