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

Published: August 9, 2026Updated: August 17, 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 after surgery."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
88190-4
Short code
Crimean-Cngo vr IgM Ser Ql IA
Synonyms
Crimean-Cngo vr IgM Ser Ql IA
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Critical range
0.5 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 CRP Matters in Your Health

CRP is a marker that rises when your body fights inflammation. High levels may signal infections, injuries, or conditions like arthritis or heart disease. Your doctor may order this test to check for hidden inflammation or guide treatment decisions.

What to Expect Before the Test

No special preparation is needed. You’ll provide a blood sample drawn from your arm. If you’re on blood thinners, let your doctor know—it may affect results.

Common Uses and When It’s Ordered

Doctors often use CRP to monitor chronic conditions (e.g., rheumatoid arthritis), check for infections, or assess recovery after surgery or trauma. It’s also sometimes used as a screening tool for heart disease risk.

What the Results Mean

Results are typically reported in milligrams per liter (mg/L). Very low levels may indicate no active inflammation, while elevated levels could point to underlying issues. Your doctor will interpret results in the context of your overall health.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

CRP is a sensitive but nonspecific marker. While it doesn’t pinpoint the cause of inflammation, it helps track disease activity, response to treatment, or detect early signs of complications. For example, it’s used alongside other tests to evaluate cardiovascular risk or guide decisions about steroids or biologics in autoimmune diseases.

Short name

CRP (Serum/Plasma)

Frequently asked questions

How often is CRP tested?
CRP testing frequency depends on your condition. Some people get it yearly for general health checks, while others may have it more often if they have chronic illnesses like arthritis or heart disease. Your doctor will determine the best schedule for you.
What if my CRP is high?
A high CRP level may signal inflammation, but it doesn’t always mean you have a specific illness. Common causes include infections, injuries, or autoimmune diseases. Your doctor will review your symptoms, medical history, and other test results to figure out what’s going on and recommend next steps.
Can diet or exercise affect CRP levels?
Yes! Lifestyle factors like diet (e.g., Mediterranean diet), exercise, and weight management can influence CRP levels. Reducing inflammation may lower CRP, so small changes—like eating more fruits, vegetables, and omega-3s—could help.
  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 17, 2026. · Read our editorial policy