Written question WQ82777
- Asked by
- Samuel KurtzConservative
- To be answered by
- Minister for Rural Affairs and North Wales, and Trefnydd
- Tabled
- Due
- Answered
- Time to answer
- 12 days
Question
Will the Minister provide a breakdown of the number of false negatives from pre and post movement TB tests issued for cattle by area in the years 2019-20 and 2020-21?
Answer
Answered by Minister for Rural Affairs and North Wales, and Trefnydd
The sensitivity of the skin test at standard interpretation is considered to be on average 81%, but can vary between 50% and 90% depending on conditions. Sensitivity is the probability that an infected animal will test positive to the test and a sensitivity of 80% means on average 20 out of 100 infected animals will not be accurately identified by the test. There is no way of identifying from historical pre- and post-movement testing data which cattle negative to the skin test at standard interpretation were truly uninfected and which were truly infected (and were therefore false negatives to the test).