If diagnosis as the deductive medical or veterinary decision phase was a purely intellectual exercise, the feature pertaining to the diagnosis for curative purposes and the features relating to the preceding steps which were constitutive for making the diagnosis represented the essential features of a diagnostic method. Thus, in order to satisfy the requirements of Art. 84 EPC 1973, an independent claim relating to such a method had to include these features. If a non-technical feature was to be regarded as constitutive for defining the invention, it had likewise to be included as an essential feature in the independent claim.
Source: http://www.epo.org/law-practice/legal-texts/html/caselaw/2019/e/clr_i_b_4_5_1_d.htm
Date retrieved: 17 May 2021