Both ESR and CRP Are Elevated in Pericarditis
Both erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) are commonly elevated in acute pericarditis, and the 2015 ESC Guidelines explicitly recommend assessing both markers, though CRP is specifically highlighted for monitoring disease activity and treatment response. 1
Guideline Recommendations
The 2015 European Society of Cardiology (ESC) Guidelines for pericardial diseases provide clear direction on inflammatory marker assessment:
Assessment of markers of inflammation (specifically CRP) is a Class I, Level C recommendation for all patients with suspected acute pericarditis 1
Both CRP and ESR elevation are listed as "additional supporting findings" in the diagnostic criteria for acute pericarditis 1
The guidelines state that "elevation of markers of inflammation [i.e. C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR), as well as elevation of the white blood cell count] is a common and supportive finding in patients with acute pericarditis" 1
Clinical Utility: CRP Is Preferred for Monitoring
While both markers are elevated, CRP has superior clinical utility because it is specifically recommended for:
- Monitoring disease activity during the course of illness 1
- Assessing efficacy of anti-inflammatory therapy 1
- Evaluating treatment response at 1-week follow-up (Class I, Level B recommendation) 1
The guidelines specifically mention CRP—not ESR—in their formal recommendations table for inflammatory marker assessment 1.
Why Both Are Elevated But CRP Is Better
Recent research supports this guideline preference:
- In pericardial effusions with inflammation, CRP elevation guides the decision to initiate empiric anti-inflammatory treatment 2
- CRP integrates inflammatory status with hepatic synthetic function and has demonstrated prognostic value for long-term mortality in pericarditis patients 3
- While ESR and CRP have similar diagnostic accuracy in inflammatory conditions overall, CRP responds more rapidly to changes in inflammation and is less affected by confounding factors like age (which increases ESR) 4, 5
Practical Clinical Approach
Order both ESR and CRP initially for diagnosis, as either or both may be elevated and support the diagnosis of acute pericarditis. However, use CRP specifically for:
- Confirming the diagnosis when clinical criteria are equivocal
- Monitoring treatment response at 1 week
- Guiding duration of anti-inflammatory therapy
- Identifying patients who fail to respond within 7 days (a major risk factor for poor prognosis) 1
Important Caveat
Absence of inflammatory marker elevation does not exclude pericarditis. Some patients with pericardial effusion may have normal CRP and ESR, representing a distinct clinical entity without overt inflammation 2. In such cases, the diagnosis relies more heavily on clinical criteria (chest pain, pericardial rub, ECG changes, and imaging findings).