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C-reactive protein (CRP) – Serum or Plasma Substance Concentration

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

This test measures the amount of C-reactive protein in your blood, a marker often checked for signs of inflammation or infection.

Quick summary

["CRP helps track inflammation, which may signal infections, autoimmune conditions, or other health concerns."]

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

Key facts at a glance

LOINC
16639-7
Short code
C immitis IgM CSF-aCnc
Synonyms
C immitis IgM CSF-aCnc
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82784
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

Why This Test Is Done

Your doctor may order a CRP test to monitor conditions like arthritis, heart disease, or infections. It can also help check for inflammation after surgery or injury, or during routine health screenings.

What to Expect Before the Test

No special preparation is needed. You may have blood drawn from a vein in your arm, or a urine sample may be collected if testing for certain conditions. Avoid strenuous activity or certain medications for 24 hours before testing, as they may affect results.

What the Results Mean

Higher-than-normal CRP levels may indicate inflammation, infections, or autoimmune diseases. Lower levels might suggest reduced inflammation or no active condition. Results should be interpreted by your healthcare provider based on your medical history.

Common Conditions Monitored

CRP is used to assess inflammation in conditions like rheumatoid arthritis, lupus, heart disease, or after trauma. It can also guide treatment decisions for infections or post-surgical recovery.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CRP Level

Frequently asked questions

What causes elevated CRP levels?
Elevated CRP levels can result from infections (bacterial or viral), autoimmune diseases (like rheumatoid arthritis), injuries, or certain medications. Stress, smoking, or obesity may also influence CRP levels.
How often should CRP be checked?
Frequency depends on your health needs. Your doctor may recommend periodic checks for chronic conditions, post-treatment monitoring, or during flare-ups of inflammatory diseases.
Can CRP levels change with diet or exercise?
Yes, lifestyle factors like diet, exercise, and weight can affect CRP levels. Reducing inflammation through diet, managing stress, and maintaining a healthy weight may help lower CRP levels over time.
  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