ToolsCalculators
Age-adjusted ESR (and CRP) for rheumatoid arthritis
Upper limit of normal ESR corrected for age and sex, with CRP for context.
Age-adjusted ESR (and CRP) for rheumatoid arthritis
Age
years
Sex
Measured ESR
mm/hr
Measured CRP (optional)
mg/L
Complete the fields above to see the result.
When to use
- Judging whether an ESR is truly elevated in older adults, in whom the normal range rises with age.
- Supporting the 'abnormal CRP or ESR' criterion used in inflammatory arthritis classification schemes.
Formula
ESR upper limit of normal = age / 2 for men; (age + 10) / 2 for women (Miller's rule). No comparably validated age-adjustment formula exists for CRP; a conventional upper limit of about 10 mg/L is used for context.
Pearls and pitfalls
- ESR rises physiologically with age even without disease, so unadjusted cut-offs overcall inflammation in the elderly.
- CRP is less affected by age than ESR but is not immune to it; interpret borderline values in clinical context.