Table 1.
The main features of the five automated immunoassay methods, as declared by the manufacturers
| System | Method | Tracer | Antigen | Imprecision (%): intra-assay; between-assay | Imprecision (%): total | LoD (IU/mL) | LoQ (IU/mL) |
|---|---|---|---|---|---|---|---|
| IMM | CLIA | Luminescence: adamantyl dioxetane phosphate | Native TPO | 4.9–6.3; nr | 6.1–8.1 | 5.0 | nr |
| MAG | CLIA | Luminescence: N-(aminobutyl)-N-(ethyl)-isoluminol | Native TPO | 6.8–7.3; 7.4–7.6 | nr | 0.38 | nr |
| KRY | FIA | Fluorescence: europium cryptate/XL 665 | Native TPO | 2.1–7.6; 5.8–16.0 | nr | 1.8 | 9.0 |
| PHA | FEIA | Fluorescence: β-D-galactosidase; 4-methyl-umbelliferyl-β-D-galactoside | Recombinant TPO | 4.1–4.7; 2.5–4.8 | nr | nr | nr |
| LIA | CLIA | Luminescence: isoluminol derivative | Recombinant TPO | 3.6–6.2; 4.7–6.9 | nr | 0.6 | 1.0 |
CLIA chemiluminescence immunoassay, FEIA fluorescence enzyme immunoassay, FIA fluoroimmunoassay, IMM Immulite 2000 XPi, KRY Kryptor Compact Plus, LIA Liaison XL, LoD limit of detection, LoQ limit of quantitation, MAG Maglumi 2000 Plus, nr not reported, PHA Phadia 250, TPO thyroid peroxidase