Summary of performance of the IFN-γ PCR and Brock tests for diagnosis of M. bovis infection in badgers

TestaSensitivity (%)bSpecificity (%)bPPV (%)cNPV (%)dAccuracy (%)e
PCR64.2 (49.8-76.8)f93.3 (88.8-96.4)72.3 (57.3-84.4)90.5 (85.6-94.2)87.0
BT52.9 (38.4-67.1)90.7 (85.7-94.4)60.0 (44.3-74.3)87.9 (82.6-92.1)82.8
  • a The cutoffs for both tests are as indicated in Tables 2 and 4 for PCR and the Brock test, respectively.

  • b Culture was taken as the standard against which the two tests were compared.

  • c PPV, positive predictive value (percentage of positive tests confirmed by culture).

  • d NPV, negative predictive value (percentage of negative tests confirmed by culture).

  • e Percentage of test results in agreement with the culture results.

  • f The 95% CIs are shown in parentheses.