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Table 5 Results from two cut offs of Ct 40 and 35 from the aprB2 rtPCR and aprV2 rtPCR obtained from two runs, in 72 sheep randomly sampled from 3 flocks considered having virulent footrot

From: Assessment of a rtPCR for the detection of virulent and benign Dichelobacter nodosus, the causative agent of ovine footrot, in Australia

Foot lesion Cut off 40 Cut off 35
Run 1 + ve Run 1 -ve Run 2 + ve Run 2 -ve Run 1 + ve Run 1 -ve Run 2 + ve Run 2 -ve
aprB2
 Positive 9 28 8 29 7 30 7 30
 Negative 2 33 1 34 1 34 1 34
 Overall % positive   15.30%   12.50%   11.10%   11.10%
 McNemars two tailed p value   < 0.0001   < 0.0001   < 0.0001   < 0.0001
aprB2 cut off agreement
 Run 2 + ve 8 1    8 0   
 Run 2 -ve 3 60    0 64   
 Kappa 0.768 “good”    1 “perfect”   
aprV2
 Positive 33 4 33 4 30 7 29 8
 Negative 19 16 23 12 15 20 16 19
 Overall % positive   72.20%   77.80%   62.50%   62.50%
 McNemars two tailed p value   0.0035   0.0005   0.1356   0.153
aprV2 cut off agreement
 Run 2 + ve 51 5    44 1   
 Run 2 -ve 1 15    1 26   
 Kappa 0.779 “good”    0.941 “very good”   
  1. The p-value for McNemar’s test for independence between lesion score and rtPCR result is shown along with kappa statistic for agreement between rtPCR runs