20.—(1) This article applies where—
(a)the keeper of a breeding herd has taken (or arranged to have taken) samples described in article 9(3)(b), (4) or (5),
(b)the keeper has arranged for the testing of the samples by an approved laboratory in accordance with article 18, and
(c)the samples have been submitted to an approved laboratory.
(2) Where this article applies, the operator of the approved laboratory must—
(a)test each of the samples for evidence of exposure to BVDV, and
(b)determine whether or not any of the samples show evidence of exposure to BVDV.