Use of the erythrocyte sedimentation rate in chronically ill, elderly patients with a decline in health status.

A decline in health status in a chronically ill, elderly patient could mean the progression of a known disease, depression, or the development of a new disease. The value of the erythrocyte sedimentation rate in selecting patients in whom the likelihood of a new disease is high enough to warrant a diagnostic evaluation was studied. Subjects included long-term residents of a chronic-care hospital over age 65 in whom the erythrocyte sedimentation rate was determined because of a nonspecific, subacute change in health status (n = 98) or new, unexplained musculoskeletal complaints (n = 44). The target erythrocyte sedimentation rate-elevating diseases included infections, connective tissue diseases, and malignancies. Among the group with subacute deterioration, post-test probabilities (incorporating clinical data with test results) of a new disease ranged from 7 percent in those with an erythrocyte sedimentation rate below 20 mm per hour to 66 percent in those with a rate of 50 mm per hour or more. The comparable probabilities among the group with musculoskeletal complaints were 3 percent and 57 percent. The erythrocyte sedimentation rate, an inexpensive test, although nonspecific, appears useful in deciding when to pursue expensive, and sometimes uncomfortable or hazardous, diagnostic evaluations. The erythrocyte sedimentation rate is most useful among patients in whom the probability of disease is moderate (neither very high nor very low) following initial history-taking and examination.