# Council Directive of 26 June 1964 on animal health problems affecting intra-Community trade in bovine animals and swine (64/432/EEC), Division 9: The test may be read at 24 and 48 hours but a final result shall not be obtained before 72 hours:

Extent: E+W+S+N.I.

(a) a test serum is positive if it forms a specific precipitation line with the bovine leukosis virus (BLV) antigen and forms a complete line of identity with the control serum;
(b) a test serum is negative if it does not form a specific precipitation line with the BLV antigen and if it does not bend the line of the control serum;
(c) the reaction cannot be considered conclusive if it:
(i) bends the line of the control serum towards the BLV antigen well without forming a visible precipitin line with the antigen; or
(ii) if it cannot be read either as negative or as positive.
In inconclusive reactions the test may be repeated and concentrated serum utilised.

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Source: https://www.legislation.gov.uk/eudr/1964/432/annex/D/chapter/II/division/A/division/9 (the official version)
Page: https://openlegislation.uk/eu-directive-1964-432/annex-D/chapter-II/division-A/division-9
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.