Plans are underway to establish a specialist interferon-gamma testing laboratory for bovine TB in England. The government-run facility will be based at the Animal and Plant Health Agency (APHA) lab at Thirsk, North Yorkshire. The interferon-gamma test (or 'gamma' test for short) is a supplementary blood test used alongside the skin test to maximise the probability of detecting TB-infected animals in cattle herds affected by TB breakdowns.

Interferon-gamma testing

Interferon-gamma testing is more sensitive than the traditional skin test (detecting around 90% of infected animals compared to 81% with the skin test). However, it also has a lower specificity, which equates to three or four false positives for every 100 disease-free animals tested. It compares to one false positive per 5,000 disease-free animals tested with the skin test. The introduction of private interferon-gamma testing was one of the objectives in Defra’s current strategy for achieving Officially TB-free status for England. It's currently available in England under certain conditions, such as:
  • To supplement pre or post-movement testing of animals that are not subject to, or have passed a compulsory skin test;
  • To screen animals joining high-value herds, including pedigree bulls entering semen collection centres;
  • To test animals following a negative routine or tracing skin test;
  • As a marketing tool to add value to herds/animals intended for sale;
  • Rapid retesting of inconclusive skin test reactors (before or after the skin re-test) where no government-funded gamma test is planned.

7 days a week service

The purpose of this TB Gamma testing team is to provide laboratory diagnostic testing and reporting in support of the TB eradication programme. It's expected the seven-days-a-week service will take around seven members of staff to run with APHA currently recruiting across a range of specialist positions. The tests will be carried out on blood samples received from APHA sampling carried out on farms. APHA employs around 2,300 staff and is responsible for identifying, managing and eradicating incidences and outbreaks of endemic and exotic diseases and pests in animals, plants and bees in the UK. Its work is mainly for Defra covering England and Wales but it also carries out services for the other devolved UK nations.
APHA BOVINE TB DEFRA