Table 2.
Diagnostic performance of different reference interval recommendations as compared to the reference standard
| Treatment indication | Treatment consideration | Overt hypothyroidism | Overt hypothyroidism and TPOAb+ | Subclinical hypothyroidism | Subclinical hypothyroidism and TPOAb+ | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sensitivity | FDR | Sensitivity | FDR | Sensitivity | FDR | Sensitivity | FDR | Sensitivity | FDR | Sensitivity | FDR | |
| First trimester (N = 35 778) | ||||||||||||
| 4.0 mU/L fixed limit approach | 0.77 (0.58-0.89) | 0.11 (0.05-0.22) | 0.70 (0.50-0.85) | 0.27 (0.14-0.45) | 0.55 (0.35-0.74) | 0.40 (0.20-0.63) | 0.56 (0.38-0.73) | 0.41 (0.21-0.64) | 0.67 (0.42-0.85) | 0.18 (0.11-0.27) | 0.69 (0.49-0.84) | 0.24 (0.16-0.35) |
| Subtraction approach | 0.74 (0.55-0.87) | 0.16 (0.08-0.27) | 0.63 (0.46-0.77) | 0.35 (0.21-0.52) | 0.55 (0.34-0.74) | 0.41 (0.23-0.61) | 0.56 (0.37-0.74) | 0.38 (0.22-0.57) | 0.63 (0.37-0.83) | 0.23 (0.15-0.35) | 0.67 (0.45-0.84) | 0.30 (0.20-0.43) |
| Non pregnancy approach | 0.60 (0.42-0.76) | 0.11 (0.06-0.19) | 0.64 (0.39-0.83) | 0.33 (0.18-0.53) | 0.49 (0.33-0.65) | 0.35 (0.19-0.55) | 0.54 (0.37-0.70) | 0.38 (0.21-0.58) | 0.47 (0.22-0.73) | 0.19 (0.12-0.30) | 0.55 (0.30-0.78) | 0.28 (0.18-0.41) |
| Second trimester (N = 16 718) | ||||||||||||
| 4.0 mU/L fixed limit approach | 0.82 (0.65-0.92) | 0.24 (0.10-0.47) | 0.68 (0.53-0.80) | 0.27 (0.17-0.39) | 0.84 (0.55-0.96) | 0.65 (0.33-0.87) | 0.84 (0.55-0.96) | 0.65 (0.43-0.82) | 0.61 (0.42-0.76) | 0.21 (0.11-0.36) | 0.65 (0.49-0.78) | 0.26 (0.14-0.43) |
| Subtraction approach | 0.82 (0.58-0.94) | 0.28 (0.13-0.50) | 0.70 (0.52-0.84) | 0.34 (0.19-0.53) | 0.72 (0.50-0.87) | 0.71 (0.37-0.91) | 0.82 (0.56-0.94) | 0.67 (0.40-0.86) | 0.64 (0.39-0.83) | 0.26 (0.13-0.46) | 0.72 (0.43-0.90) | 0.33 (0.19-0.50) |
| Non pregnancy approach | 0.66 (0.45-0.82) | 0.29 (0.14-0.49) | 0.59 (0.45-0.72) | 0.32 (0.20-0.47) | 0.69 (0.47-0.84) | 0.67 (0.36-0.88) | 0.74 (0.53-0.88) | 0.64 (0.39-0.83) | 0.43 (0.24-0.64) | 0.21 (0.10-0.38) | 0.52 (0.31-0.72) | 0.34 (0.20-0.52) |
Data are presented as effect estimate (confidence interval). Reference standard = trimester specific approach, FDR = false discovery rate – proportion of false positive test results among all positive test results. A treatment indication was defined as either overt hypothyroidism, or subclinical hypothyroidism with TSH > 10 or with concomitant TPOAb positivity, a treatment consideration was defined as a TSH > 2.5 mU/L with concomitant TPOAb positivity or subclinical hypothyroidism without TPOAb positivity.
Abbreviations: TSH, thyroid-stimulation hormone; TPOAb, thyroid peroxidase antibody.