Inflammatory MarkerInternal Medicine

C-Reactive Protein (CRP)

Normal Range
< 10.0 mg/L
Sample Type
Serum
Fasting
No
Unit
mg/L

Function

C-Reactive Protein (CRP) is an acute-phase reactant protein produced by the liver. Its levels rise rapidly in response to inflammation caused by infection, injury, or chronic disease. It is part of the innate immune system and helps the body's defense mechanisms clear pathogens.

Why it is Ordered

CRP is a highly sensitive but non-specific marker. It is used to:

  • Detect or monitor serious bacterial infections (like sepsis).
  • Monitor the activity of chronic inflammatory conditions (like Rheumatoid Arthritis or Lupus).
  • Evaluate the response to antibiotic or anti-inflammatory treatment.
  • Differentiate between viral (usually low CRP) and bacterial (usually high CRP) infections.

Associated Conditions

  • Infections: Bacterial, viral, or fungal infections.
  • Autoimmune Diseases: Rheumatoid arthritis, Vasculitis, or IBD (Crohn's/Colitis).
  • Tissue Injury: Trauma, surgery, or myocardial infarction (heart attack).
  • Malignancy: Certain cancers can cause elevated CRP.

Interpretation in Context

CRP must be interpreted alongside clinical symptoms. While a high CRP confirms inflammation, it does not point to the specific location or cause. Recent trends use 'hs-CRP' (High-Sensitivity CRP) for cardiovascular risk assessment, whereas standard CRP is used for clinical inflammation.

Check Your Result

Check Your Result

Interactive
mg/L

Enter your lab result to see where you stand compared to the standard reference range.

Why Context Matters

CRP is extremely sensitive to minor, transient factors. A recent minor injury, a common cold, intensive exercise, or even smoking can raise CRP levels. Pregnancy and the use of oral contraceptives also influence results. A second test after 2 weeks is often recommended to confirm if an elevation is chronic or acute.

Lab ranges are statistical averages, not biological laws. "Normal" for a 20-year-old male isn't normal for a 60-year-old female.

Clinical References

Source-of-truth databases and clinical guidelines for C-Reactive Protein (CRP):

Research & Guidelines

Related Indicators

DR

Medically Reviewed by Dr. Binoy Babu, MBBS

Board Certified Doctor • 10+ Years Clinical Experience

Dr. Babu is a practicing physician dedicated to empowering patients with clear, actionable medical information. He founded 2opi to bridge the gap between complex lab reports and patient understanding, ensuring everyone has access to a reliable second opinion.

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