How are test results interpreted?

Information on how the tuberculin test results are interpreted.

Interpretation of the tuberculin test has been developed over many years from experimental work in laboratories and millions of actual tests. It has been developed in many countries and here in Northern Ireland we use the results of over 10 million animal tests to allow us to set the best interpretation levels.

Using the readings obtained at the tuberculin test the veterinary surgeon performing the test classifies each animal as negative, inconclusive or as a reactor.

Where infection is confirmed in a herd, a more stringent assessment of the rest of the test results may be carried out. This is called severe interpretation. The test history of the herd and of the herds in the local area is examined. Herds from which reactors may have originated may also be checked. As a result of these investigations, the Divisional Veterinary Office may decide to classify further animals in the herd as reactors or as inconclusives.