Avoiding laboratory test misinterpretation in geriatric rheumatology

Abstract

In this review, basic principles of test selection and interpretation are applied to those serologic studies of most value to the clinician attempting to diagnose rheumatic disease in the elderly--erythrocyte sedimentation rate (ESR), rheumatoid factor (RF), and fluorescent anti-nuclear antibody (FANA). Essentials of each test are discussed and the significance of "normal" and "abnormal" results is illustrated in varied clinical circumstances. None of the tests is diagnostic and because false positive results are more common in healthy elderly subjects, the clinician faces the pitfall of overdiagnosis. Clinical findings remain the cornerstones for the diagnosis of rheumatic disease, and selected tests are used to refine the pretest assessments of disease probability.