CRP vs ESR: What Is the Difference?

CRP and ESR are both inflammation markers but behave differently.

CRP (C-Reactive Protein)

• Rises within 6–8 hours of inflammation
• Normalizes within 3–7 days after resolution
• More sensitive for acute changes
• Better for monitoring treatment response

ESR (Erythrocyte Sedimentation Rate)

• Rises over days to weeks
• Stays elevated for weeks after resolution
• Increases with age (normal range changes)
• Better for chronic inflammation monitoring

When to Use Which

• Acute infection: CRP preferred
• Chronic inflammation: ESR + CRP together
• Temporal arteritis: ESR classically very high
• RA monitoring: both used

Both Are Non-Specific

• Neither tells you WHAT is causing inflammation
• Only that inflammation exists
• Must interpret with clinical picture