3.1 Cut-off of iELISA
Assuming the molecular detection of MYXV/ha-MYXV as reference diagnostic
test, the cut-off RI10 = 6.1 yielded an estimated positive predictive
value of 96.4%
(CI95% 82.6 –
98.0%), a specificity of 99.1% (CI95% 95.2 – 100%)
and a sensitivity of 52.9%
(CI95% 38.5
-67.1%). The area under the ROC curve was estimated at 79.2%
(CI95% 69.7 –
88.7%). The finite mixture model estimated the seronegative subgroup as
a normal distribution of RI10 with mean = 0.803 and standard error =
1.714. Under the assumption of normality of the log transformed RI10
seronegative data, the cut-off RI10=6.1 yielded an estimated specificity
of 99.9%.