It is often forgotten that an erythrocyte sedimentation rate (ESR) can in fact be adapted for age and gender as published by Miller et al. in 1983.1

If their simple formula for maximum normal ESR (for men, age in years ÷ 2)* is used then the 72 year old man quoted in Hamilton and colleagues’ article on inflammatory markers would have been allowed to have an ESR of up to 36 without the clinician having to regard it as elevated.

This easy manoeuvre greatly increases the positive predictive value of ESR testing and makes ESR far more useful in clinical practice than plasma viscosity (PV).

* for women: (age in years + 10) ÷ 2

Miller A, Green M, Robinson D. Simple rule for calculating normal erythrocyte sedimentation rate. Br Med J (Clin Res Ed) 1983; 286: 266

Competing interests: None declared