Clinical significance of extreme elevation of the erythrocyte sedimentation rate.

Charts of 1006 consecutive outpatients were reviewed to ascertain the cause of extreme elevation of the erythrocyte sedimentation rate (ESR) (greater than or equal to 100 mm/h) and the sensitivity of marked ESR elevation in patients with disorders commonly reported to cause ESR elevation. Prevalence of ESRs of 100 mm/h or more was 4.2%. Infection was the most common cause (33%), with malignant neoplasms and renal disease each responsible for 17% and inflammatory disorders for 14%. Only 1% of all other patients had ESRs of 100 mm/h or more. An ESR of 100 mm/h or more had low sensitivity: 36% among patients with infection, 25% among those with malignant neoplasms, and 21% among patients with noninfectious inflammatory disorders. Specificity was high, both for individual disease categories (96% for malignant neoplasms and 97% for infection) and as a "sickness" index (greater than 99%). The positive predictive value for an identifiable cause of marked ESR elevation was 90%.