Table 2.
Comparison of antibody-capture enzyme-linked immunosorbent assay (ELISA) utilizing recombinant turkey coronavirus (TCoV) nucleocapsid (N) protein as coating antigen with immunofluorescent antibody assay (IFA) for detection of antibody to TCoV.
| Total no. samples | IFA |
ELISAc |
Relative | Relative | Agreementf | ||
|---|---|---|---|---|---|---|---|
| +a | −b | + | − | Sensitivityd | Specificitye | ||
| 322 | 101 | 87 | 14 | 86.0% | 95.6% | ||
| 221 | 7 | 214 | 96.8% | ||||
Serum sample positive for antibody to turkey coronavirus (TCoV) in IFA.
Serum sample negative for antibody to TCoV in IFA.
The optimium cutoff ELISA value (S/P ratio) of 0.20 was obtained by logistic regression method as described in materials and methods. Serum sample had ELISA value higher or lower than the cutoff value was positive (+) or negative (−), respectively, in ELISA.
Relative sensitivity= 87/(87 + 14) × 100%.
Relative specificity= 214/(7 + 214) × 100%.
Agreement = (87 + 214)/(87 + 14 + 7 + 214) × 100%.