Diagnostic sensitivity of thyroid autoantibodies assessed in a population-based, cross-sectional study in adults.

The aim of this study was to estimate the diagnostic sensitivity of thyroid autoantibodies in individuals with a case-mix of subjects with thyroid disease representing that of the general population. We measured thyroid microsome (TMA), thyroid peroxidase (TPO), thyroglobulin (TGA) and thyroid-stimulating hormone (TSH) receptor (TRA) autoantibodies in subjects in the bottom (hyperthyroid end) and top (hypothyroid end) four percentiles of the TSH distribution from among participants in a population-based survey of individuals aged ≥40 years (the Cremona Study). TMA and TPO were the most sensitive autoantibodies in subjects in both the bottom percentiles (19.8% and 18.5%, respectively) and the top percentiles (51.2% and 53.8%, respectively) of the TSH distribution. TMA and TPO showed good agreement (kappa statistics 87.8%, 95% CI 80.1-95.5%) at both ends of the TSH distribution. TGA were the next most sensitive marker, although seldom detected if TMA or TPO were not present. TRA were detected only at the extremes of the TSH distribution (1st percentile, 31.8%; 100th percentile, 25.0%). We conclude that, among a case-mix of individuals with thyroid disease representing that of the general population, TMA and TPO are the most sensitive markers of thyroid disease. TGA only marginally increased the diagnostic sensitivity of TMA and TPO. TRA are sensitive markers of thyroid disease only at the extremes of thyroid function.