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

Aim of our study was to estimate the diagnostic sensitivity of thyroid autoantibodies in individuals with a case-mix of thyroid disease representing that of the general population. We measured thyroid microsome (TMA), thyroid peroxidase (TPO), thyroglobulin (TGA) and TSH receptor (TRA) autoantibodies in the lower (hyperthyroid end) and upper (hypothyroid end) four percentiles of the TSH distribution among participants of a population-based survey of individuals aged ≥40 years (the Cremona Study). TMA and TPO were the most sensitive autoantibodies in both the lower (19.8% and 18.5%, respectively) and upper (51.2% and 53.8%, respectively) percentiles of the TSH distribution. TMA and TPO showed good agreement [kappa statistics: 87.8% (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 individuals with a case-mix of thyroid disease representing that of the general population, TMA and TPO were the most sensitive markers of thyroid disease. TGA only marginally increased the diagnostic sensitivity of TMA and TPO. TRA were sensitive markers of thyroid disease only at the extremes of thyroid function.