Defra has provided financial and other support for research on a number of candidate diagnostic tests for M. bovis, the causative agent of tuberculosis in cattle, and continues to do so.
Neither the Phage nor PCR tests are currently validated to OIE (World Organisation for Animal Health) level for use in diagnosing TB in bovine species. If and when the manufacturers validate their tests we would consider their official use in TB control.
In exceptional circumstances, non-validated tests may be carried out on bovine species under strict criteria with the approval of the Secretary of State. This allows diagnostic companies to undertake the work required to validate the test.
The PCR test used in this instance is the same as that previously used to detect M. bovis in badger faeces and a comprehensive assessment of the PCR test (Defra study SE3289) indicated that this PCR test was not suitable for use in TB surveillance activities in wildlife. Until the PCR test is validated for use in cattle it is difficult to determine the percentages of truly TB-infected and TB-free animals that are correctly identified by this method.