For years, applicants relied on the assumption that medical diagnostic software analyzing previously acquired physiological data and outputting diagnostically relevant results could meet the technicality requirement under Article 52(1) EPC. This understanding was supported by case law such as T 2681/16 and long reflected in the EPO Guidelines. However, decision T 1741/22 casts doubt on this long-standing understanding. Has the bar for technicality been raised? And what does this mean for the way we draft applications in this field?
To assess the extent of this change, it is necessary to first revisit how the Enlarged Board in G 1/19 defined the concept of technical character in the context of computer-implemented inventions — a definition that had shaped expectations and practice in this field until now.
What Does G 1/19 Say About Technical Character?
G 1/19 (March 2021) clarified that technical character for computer-implemented inventions can be established in three principal ways:
- Through interaction with the physical world at the input level, such as measuring data.
- Through interaction with the physical world at the output level, for example by controlling a machine or by specifying that the output is to be used for a technical purpose.
- Through adapting the internal functioning of a computer system.
The Enlarged Board in G1/19 par. 88 further clarified that, following existing case law, there is no need for a direct link with (external) physical reality in every case to establish technicality. Rather, “[…] there are many examples in which potential technical effects - which may be distinguished from direct technical effects on physical reality - have been considered in the course of the technicality / inventive step analysis […]. While a direct link with physical reality […] is in most cases sufficient to establish technicality, it cannot be a necessary condition, if only because the notion of technicality needs to remain open”.
An example for this may be a claim to a defibrillation pulse sequence. In G1/19 par. 101, the Enlarged Board “fully supports the view expressed in T 533/09 […] that a tangible effect is not a requirement under the EPC. […]“. In the decision T 533/09, claims to a defibrillation pulse sequence (see patent EP 1 284 788 B1) were held allowable. The claimed pulse sequences were likened by the Enlarged Board to control signals having potential further technical effects when put to their intended use.
Put in a nutshell, G1/19 clarified that establishing technical character can result from a direct link to the physical world, either at the input or output level or through adaptations to the internal functioning of a computer. However, such a direct link is not a strict prerequisite in all cases. It may be sufficient, for example, that the output data is capable of producing further technical effects when put to its intended use.
What was the legal framework for Diagnostic Software before T 1741/22 ?
In medical diagnostics, explicitly claiming a measuring step (interaction at the input level) often triggers Article 53(c) EPC, which excludes diagnostic methods “practised on the human body” from patentability. To avoid this, claim drafters frequently leave out the measuring step and instead focus on analysing data already collected and on outputting diagnostically relevant information. The output is typically presented to a user to enable the user to make a diagnostic decision, but is typically not used for directly controlling a device.
Nevertheless, and in line with G1/19, the EPO Guidelines (G-II, 3.3) since 2019 till their current version 2025, acknowledge that even mathematical methods may be regarded as technical if they are applied to physiological data for medical diagnostic purposes by an automated system..
Also in T 2681/16 (March 2022), the Board took a favorable stance toward such drafting strategies. While it denied technicality of the patient data processing steps themselves, i.e. the algorithm, it recognized technicality based on the output. Specifically, the claim related to a system that calculated and outputted hypo- and hyperglycemic risk values. The Board acknowledged that this output supported diabetes management and therapy assessment, conferring technical character on the claim as a whole. The technicality stemmed not from how the data was processed, but from the therapeutic relevance of what was output: “providing an overall measure of the glucose variability […] and a prediction of glycemic events” were considered by the board to represent a technical problem .
How Does T 1741/22 Challenge That Framework?
T 1741/22 (July 2024) presents a direct challenge to this established line. The subject matter concerned a method and system for analyzing already measured continuous glucose monitoring (CGM) data to determine and display minima and maxima. The applicant argued that outputting such values provided diagnostic value, especially in assessing glycemic variability.
The Board rejected this argument, stating that computing and displaying minimum and maximum values of pre-existing data is a mathematical method and therefore non-technical. It emphasized that the claim involved no interaction with the physical world and hence did not fulfil the requirements for an actual “measurement” or even “indirect measurement” in accordance with G 1/19, Reasons 99. For the Board, the diagnostic relevance of the output was not enough to establish technicality: “[..] generating (and displaying) further data [creatd] by an evaluation or interpretation of these measurements […] amounts to "measurements" generated merely by a cognitive or mathematical exercise that is inherently non-technical.”.
This focus on the interaction with the physical world at the input level poses a challenge to the above-mentioned framework, as in view of G 1/19, Reasons 88, 100 and 101, a method that lacks interaction with the physical world at both the input and output levels may still be considered technical, provided that its output solves a technical problem when put to its intended use. While the absence of interaction at the input level may disqualify a method from being classified as a direct or indirect “measurement” method, the assessment of its overall technical character — in light of G 1/19 — requires further examination of whether the output has “potential further technical effects when put to its intended use”. The Guidelines G-II, 3.3 appear to implicitly acknowledge this potential further technical effect for diagnostic methods. T 1741/22 does not.
Did the Board in T 1741/22 Misread G 1/04?
The board in T 1741/22 did not consider diagnostic methods as technical, and therefore explicitly considered the Guidelines (G-II, 3.3) erroneous. To justify its position, the Board cited G 1/04 , in particular reasons 5.3 and 6.3, suggesting that diagnostic methods without preceding technical steps lack technical character. However, this interpretation is questionable — and our reasoning for that conclusion rests on a close reading of G 1/04 itself. G 1/04 is a 2005 decision addressing the correct interpretation of the terms “diagnostic method” and “performed on the human or animal body” with respect to the exclusion from patentability under the EPC. Regarding the technical character of diagnostic methods, G 1/04 held that diagnostic decisions for therapeutic purposes, as part of the deductive phase of human or veterinary medical practice, are considered purely mental activities — unless a device capable of drawing diagnostic conclusions is involved. According to Reasons 5.2, the deductive decision-making phase may qualify as an invention if the method is carried out by a device.
Only in cases where the deductive phase is purely mental (i.e., in accordance with reasons 5.2, where the decision-making occurs solely in the human mind and outside of any device), the method must additionally include preceding steps of a technical nature, which interact with the non-technical decision-making phase in such a way as to produce a technical effect.
In other words, as far as technicality is concerned, G 1/04 appears to adopt a relatively permissive approach, under which the implementation of a diagnostic method on a device may already be sufficient to establish technical character. However, this approach has since been superseded by G 1/19.
Therefore, it appears questionable whether G 1/04, Reasons 5.3, provides valid grounds for denying the technical character of the patent under appeal in T 1741/22.
In light of G 1/19, Reasons 101, the decisive question for computer-implemented diagnostic methods that lack interaction with the physical world at the input level and do not modify the functioning of the computer is whether the generated output has “potential further technical effects when put to its intended use.” This question is not addressed in G 1/04.
In the author’s view, the typical use of displayed minimum and maximum glucose values is to assess glycemic variability and, consequently, adapt and improve the treatment regimen. This typical use appears to clearly serve technical purposes, as improvements in the fields of medicine, pharmaceuticals, diagnostic devices, and software supporting medical decision-making are generally considered part of technology under the EPC. While it may be debated whether a further concretization of the intended use of the output is necessary to exclude also non-typical and non-technical uses (e.g., purely informative purposes, see G1/19 reasons 98), it seems at least that G 1/04 does not provide basis for proving the Guidelines G II 3.3 wrong.
This view is supported not just by our reading of G 1/04 but also by the fact that the Guidelines since 2019 have consistently accepted diagnostic methods using automated systems as potentially technical, a position incompatible with the restrictive interpretation in T 1741/22. Notably, even though an updated version of the Guidelines for Examination at the EPO was released in April 2025, G-II, 3.3 was not amended in view of T 1741/22.
That a physical interaction with the physical world is not a prerequisite for techniciality in the context of computer-implemented diagnostic or therapeutic methods is also reflected in later case law: for example, T 1814/07 considered it improper to simply discount medical aspects of the claim in the assessment of inventive step for medical systems. According to T 533/09, a claim to a defibrillation pulse sequence as such, and a process for the forming of the same, was considered technical, even without any reference to a computer or an apparatus.
How to draft claims for Diagnostic Software?
Despite the disruption caused by T 1741/22, there is no immediate need to revise the standard approach to drafting claims for diagnostic software. However, the contrast between T 2681/16 and T 1741/22 underscores a key consideration: the technical complexity of the claimed invention may matter. A comparison of the technically complex computation of a risk value from blood glucose measures in T 2681/16 — where a technical effect was acknowledged — and the technically much simpler identification and output of minima and maxima in T 1741/22 — where technicality was denied — suggests a clear message.
Drafting very broad or uncomplex claims, particularly in the field of diagnostic methods, involves a significant risk of rejection for lack of technical character, not merely for lack of inventive step. The danger lies in the way examiners apply the established "Comvik approach": prima-facie non-technical aspects of the claim are ignored from the outset when assessing inventive step. If the claim is perceived as lacking a sufficiently impactful technical contribution, even diagnostically relevant aspects might be excluded from consideration. Once a method is classified as non-technical, it becomes extremely difficult to requalify it as inventive by subsequently adding detail. In contrast, a carefully drafted claim from the beginning — one that frames non-trivial data analysis for medical purposes as a technically meaningful activity, and that ideally limits the use of the output to clearly technical/diagnostics-related uses — has a much better chance of being recognized as technical in the first place and then evaluated properly for inventive step.
Careful claim drafting is therefore not only a matter of satisfying formal requirements, but a strategic step to ensure that the invention is not misunderstood as an abstract or purely intellectual exercise, and to ensure that the diagnostic relevance of the output is immediately apparent. Avoiding generic or simplistic claim formulations may make the decisive difference in prosecution.
Will T 1741/22 Stand the Test of Time?
The reasoning in T 1741/22 sits in clear contradiction to both the EPO Guidelines and earlier decisions. This makes it likely that T 1741/22 will remain an isolated outlier — unless adopted by other Boards or escalated for clarification by the Enlarged Board of Appeal. Until then, applicants should be cautious when relying solely on the technical effect of the outputs for technicality and should avoid overly generic mathematical processing steps in their claim language.
We will continue to monitor future developments and update our drafting strategies as needed. For now, diagnostic outputs still matter — but their diagnostic and hence technical relevance over the whole claim scope must be immediately apparent.
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Author: Dr. Thorsten Barnickel