PCR Testing For Bovine TB

The Animal Plant Health Agency (APHA) is set to begin using a new PCR test which would be automatically applied to the tissue samples collected at post mortem in prescribed scenarios to detect the bacterium that causes bovine TB. These scenarios include situations such as for slaughterhouse cases in cattle found to have suspicious lesions, and for all post mortems of non-bovine animals which have been compulsorily slaughtered for suspicion of TB.

A major advantage is this now means that it would take only three weeks to get a test result and means that movement restrictions can be lifted much more quickly following the veterinary enquiry. Farmers do not need apply for this to take place – it will be undertaken as standard procedure in applicable scenarios.

Though Scotland achieved Officially TB Free Status in September 2009, this does not mean that bovine tuberculosis has been eradicated entirely but recognises that we have relatively few cases below the threshold for that designation.


The new tests will be used from Wednesday 30th March 2022.

Accurate diagnostic and confirmatory testing is the cornerstone of any disease eradication programme. The current “gold standard” method for bTB testing from tissue samples (for bovine and non-bovine farmed animals) remains traditional microbiological culture. However, although well established, it takes between 6 and 22 weeks to obtain a final result from that process.

The use of PCR will mean that in certain circumstances farmers will receive the results of whether TB is present or not more quickly than they would have previously.

How will the new test be used by APHA?

The test will be used (as ‘business as usual’) in Great Britain for tissue samples from carcases of:


  • TB slaughterhouse cases in cattle and non-bovines i.e. animals routinely sent for commercial slaughter with suspicious lesions of TB identified;
  • Non-bovine animals such as camelids, goats, pigs, sheep and farmed deer that are removed as TB test reactors, direct contacts or clinical TB suspects. And cases where suspicious TB lesions are identified on diagnostic post-mortem examination in a veterinary laboratory; and
  • Domestic pets (cats and dogs) and exotic species of animals (e.g. in zoological collections) submitted to APHA for laboratory investigation.


How does the accuracy of the PCR test compare with microbiological culture?

In the test validation study, the M. bovis PCR test produced equivalent results to the traditional microbiological culture method.

Further information: TB hub website – (external)

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