# Council Directive 92/66/EEC of 14 July 1992 introducing Community measures for the control of Newcastle disease, Division (b)

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

Examination for antibodies
Individual serum samples should be tested for their ability to inhibit Newcastle disease virus haemagglutinating antigen in standard haemagglutination inhibition tests as defined in Chapter 6.
There is some debate as to whether 4 or 8 haemagglutinin units should be used for the HI test. It would appear that either is valid and the choice should be left to the discretion of the national laboratories. However, the antigen used will affect the level at which a serum is considered positive: for 4 HAU a positive serum is any showing a titre of 24 or greater and for 8 HAU a positive serum is any showing a titre of 23 or greater.

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Source: https://www.legislation.gov.uk/eudr/1992/66/annex/III/chapter/4/division/2/division/b (the official version)
Page: https://openlegislation.uk/eu-directive-1992-66/annex-III/chapter-4/division-2/division-b
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.