a) What constitutes "diagnostic methods" 

In G 1/04 the Enlarged Board gave the term "diagnostic methods" a narrow interpretation: in order that the subject-matter of a claim relating to a diagnostic method practised on the human or animal body falls under the prohibition of Art. 52(4) EPC 1973, the claim is to include the features relating to: (i) the diagnosis for curative purposes stricto sensu representing the deductive medical or veterinary decision phase as a purely intellectual exercise, (ii) the preceding steps which are constitutive for making that diagnosis, and (iii) the specific interactions with the human or animal body which occur when carrying those out among these preceding steps which are of a technical nature.

The Enlarged Board pointed out that the surgical or therapeutic nature of a method claim could be established perfectly by a single method step without contravening Art. 84 EPC 1973. Diagnostic methods, however, differed in this respect from the methods of surgery and therapy. The method steps to be carried out prior to making a diagnosis as an intellectual exercise were related to examination, data gathering and comparison. If only one of the preceding steps which were constitutive for making such a diagnosis were lacking, there was no diagnostic method, but at best a method of data acquisition or data processing that could be used in a diagnostic method (see T 385/86). It followed that, whilst the surgical or therapeutic nature of a method claim could be achieved by a single method step, several method steps were required to define a diagnostic method due to the inherent and inescapable multi-step nature of such a method.

These required method steps (G 1/04) consist of: (i) the examination phase involving the collection of data, (ii) the comparison of these data with standard values, (iii) the finding of any significant deviation, i.e. a symptom, during the comparison, and (iv) the attribution of the deviation to a particular clinical picture, i.e. the deductive medical or veterinary decision phase.

In T 1255/06 the claim in question only defined the data acquisition steps (the temperature of the body) which could be used in a diagnostic method. Although the acquisition of the temperature data lead to the detection of a deviation from the normal values, it did not allow per se the attribution of the detected deviation to a particular clinical picture.

T 1232/15 related to the use of several adhesive and haptic strips for forming an aid for visually impaired people to enable line-by-line palpation of the breasts when performing a clinical breast examination. The board held that the claimed steps merely included the preparation of a diagnostic method to be performed by a visually impaired person, and that the steps constitutive for making the diagnosis were not included.

The board in T 529/19 stated that the interpretation of the scope of exclusion from patentability under Art. 52(4) EPC 1973 elaborated in Opinion G 1/04 is still valid for Art. 53(c) EPC. Claim 1 of the main request at hand defined a method "of determining skin health of an area of skin". The steps of this method included calculating a ratio between the intensities measured for two fluorescent emissions induced on the area of skin and comparing this ratio to a control ratio. In the decision under appeal, the examining division had found that the phases (i) to (iii) of G 1/04, were present in the steps of the method recited by claim 1. It further found that the phase (iv) of G 1/04 was derivable from the wording "[a] method of determining skin health" at the beginning of claim 1. The appellant contested the latter finding and submitted that the method of claim 1 did not include the attribution of the deviation to a particular clinical picture.

The board observed that claim 1 left open what the determined "skin health" was. For example, it could refer to the quotient between the two ratios being compared in step (vi) of claim 1 or to some other parameter related to skin health, which may at most be an intermediate finding of diagnostic value. Although the term suggested that some assessment of the skin health was made, neither the claim wording nor the relevant passages of the description indicated that the assessment would actually include the attribution to a particular clinical picture. Even if the method were construed as including some judgment of skin ageing for the assessed skin area, this would not represent the attribution to a particular clinical picture. Establishing that skin ageing is greater than expected for an individual would be, at most, an intermediate finding of diagnostic value. The board thus held that the method of claim 1 did not include the attribution of the deviation to a particular clinical picture, i.e. the deductive medical or veterinary decision phase and was therefore not excluded under Art. 53(c) EPC.