Another Positive Outcome for Diagnostic Methods from the Patent Appeal Board

September 23, 2021
By Melanie Szweras and Parnian Soltanipanah

The recent Patent Appeal Board (PAB) decision in Re Antibodyshop A/S (2021 CACP 35), further indicates the PAB’s willingness to find valid diagnostic method claims. In this decision, the PAB provides insight as to how to interpret the term “determining” in diagnostic method claims. The PAB held that the term “determining”, with respect to Canadian patent application 2,591,113 (the ‘113 patent application), cannot be defined to exclude a physical measuring step, when considered within the context of the patent application as a whole. The Board’s commitment to a purposive construction of the patent application is indicative of their new willingness to patent diagnostic methods.

In the past, the Canadian Intellectual Property Office (CIPO) considered diagnostic methods as unpatentable subject matter, and thus outside the definition of “invention” as defined in section 2 of the Patent Act. However, their November 2020 guidance document (PN2020–04) in response to Choueifaty v Canada (Attorney General), 2020 FC 837, altered that practice (read our article here).

In determining patentable subject matter with respect to diagnostic method claims, PN2020–04 specifically states that:

“a diagnostic method claim that defines a combination of elements that cooperate together so as to form a single actual invention that includes physical means for testing or for identifying, detecting, measuring, etc. the presence or quantity of an analyte in a sample would be considered to be patentable subject-matter and not to be prohibited under subsection 27(8) of the Patent Act” [emphasis added].[1]

PN2020–04 makes a distinction between taking a physical, versus mental step in determining the presence or quantity of an analyte in a sample, where a physical step constitutes patentable subject matter, and a mental step does not.

The ‘113 patent application encompasses methods for diagnosing renal disorders resulting from a renal insult by measuring the concentration of human neutrophil gelatinase-associated lipocalin (NGAL). However, claim 1 of the application recites: “determining the concentration of human neutrophil gelatinase-associated lipocalin (NGAL) in urine, plasma or serum sample form the human being” (emphasis added). During prosecution, the Examiner held that “determining the concentration of NGAL” was not limited to a physical step of measuring, and could encompass acquiring the information through a mental step, such as reading a report containing the values. With that determination, the Examiner held that claims 1 to 11 encompassed non-patentable subject matter.

The PAB disagreed. In taking a purposive interpretation, the PAB referred to the description and concluded that the patentee’s reference to “measuring” and “measurement” of various samples throughout the description, amounted to a physical measuring step. Based on this, the PAB concluded the term “determining” in this case meant “measuring”, and thus constituted a physical step. Thus, claims 1-11 on file were held to be directed to patentable subject matter. Although this does not mean that the term “determining” will always be defined as “measuring”; since it will depend on the specification of the patent application as a whole, this case shows the pendulum has clearly swung in the direction of allowing diagnostic method patent claims in Canada.


[1] Re Antibodyshop A/S, 2021 CACP 35; Canadian Intellectual Property Office, Patentable Subject-Matter under the Patent Act (2020).

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