Clinical utility of erythrocyte sedimentation rate and plasma protein analysis in the elderly.

The utilization and interpretation of the erythrocyte sedimentation rate in the elderly have been surrounded by controversy and confusion. To improve the understanding of the erythrocyte sedimentation rate and its determinants in the aged, a defined population of 111 ambulatory, retirement-home residents underwent thorough clinical and laboratory evaluation. Westergren erythrocyte sedimentation rate, Wintrobe erythrocyte sedimentation rate, and plasma viscosity measurements were all significantly correlated with one another as well as with plasma proteins, particularly fibrinogen and globulins. Age per se had no influence on the erythrocyte sedimentation rate in the study population. On the basis of standard upper limits of normal for younger populations, the Wintrobe sedimentation rate was most commonly abnormal and plasma viscosity least commonly abnormal. The "normal" upper limit of 20 mm/hour for Westergren sedimentation rate was also the optimal limit of normal by receiver operating characteristic analysis of the study population. Although the sensitivity of the Westergren sedimentation rate for the presence of an inflammatory condition or monoclonal gammopathy was only 0.55, the specificity was 0.96, and the positive predictive value of an elevated erythrocyte sedimentation rate being associated with a clinical disorder was 0.93. The enhanced clinical utility of the erythrocyte sedimentation rate in this population compared with other elderly populations may be due to a low prevalence of anemia and hypoalbuminemia. In such populations, the erythrocyte sedimentation rate may remain a useful clinical test, regardless of patient age.