Decoding Diagnostic Method Patents: Madras High Court Orders Grant Of Patent To Chinese University Of Hong Kong And American Company Sequenom Inc

S&A Law Offices


S&A Law Offices is a full-service law firm comprising experienced, well-recognized and accomplished professionals. S&A Law Offices aims to provide its clients (both domestic and international) with top-quality counsel and legal insights, which combines the Firm's innovative approach with comprehensive expertise across industries and a broad spectrum of modalities. Being a full-service law firm, we take pride in having the capability of providing impeccable legal solutions across various practice areas and industries and makes an endeavor to provide a 360 degree legal solution. With registered office at Gurugram and other strategically located offices in New Delhi, Mumbai, and Bengaluru, along with associate offices across India, S&A is fully equipped to provide legal services on a pan-India basis.
Certain inventions that are not eligible for patent protection in India are prohibited by Section 3 of the Indian Patents Act, 1970 (the Patents Act).
Hong Kong Intellectual Property
To print this article, all you need is to be registered or login on


Certain inventions that are not eligible for patent protection in India are prohibited by Section 3 of the Indian Patents Act, 1970 (the Patents Act). According to Section 3(i) of the act, inventions relating to "any process for the medicinal, surgical, curative, prophylactic diagnostic, therapeutic, or other treatment of human beings or any process for a similar treatment of animals to render them free of disease or to increase their economic value or that of their products" are not allowed to be patentable. It was unclear which techniques were forbidden from patenting under this clause until the Madras High Court's decision on October 12, 2023, in the case of The Chinese University of Hong Kong and Sequenom, Inc. (the Applicants) v. The Assistant Controller of Patents & Designs.

In pursuant to the appeal filed by the applicant in High court of Madras IPD (CMA/PT/14/2023) against the refusal order of instant application through order dated 31.03.2021, a judgement has been given by The Hon'ble High Court of Madras on 12.10.2023 to proceed the application with grant on the basis of the amended claims proposed by the applicant during the hearing. In view of the direction given by The Hon'ble High Court of Madras, Order dated on 12.10.2023 the amended claims 1-12 is allowed.


The appellants, the Chinese University of Hong Kong Knowledge Transfer Office, and SEQUENOM, INC., filed a patent application (IN 4812) entitled "FETAL GENOMIC ANALYSIS FROM A MATERNAL BIOLOGICAL SAMPLE" in India. The said application was examined under Section 12 and 13 of Patents Act and First Examination Report containing a statement of objections was issued and the applicant's agent filed a response to FER objcetions. The appellant received multiple objection in the First Examination Report (FER). The appellant revised claim and ultimately introduced a disclaimer stating that the invention involves a non-diagnostic method and was carried out in vitro on a biological sample. As per the provisions under Section 13 (3) of Patents Act, the said amended case after reply to Examination Report, was examined and investigated in like manner as the original specification. Further The applicant was offered a hearing on 11/06/2019 vide official communication. Controller examined the claim and came to the conclusion that the claim cannot be allowed as invention was not patentable under Section 3(i) of the Patents Act as the invention employed a diagnostic method. The dispute arose when the Assistant Controller of Patents rejected the patent application under Section 3(i) of the Patents Act, 1970, deeming it a diagnostic method, a non-patentable subject matter under S. 3 of the Patents Act.


The main issue in the present case was whether appellant's invention is non­ diagnostic in nature under Section 3(i) of the Patents Act and whether or not the Assistant Controller erred in coming to the conclusion that the invention was diagnostic.


The court went into depth while interpreting Section 3(i) of the Patents Act. It has been noted that apart from specific purposes, Section 3(i) contains the generic expression "or other treatment of human beings". The use of the disjunctive "or" followed by the expression "other treatment" indicates that it refers to forms of treatments other than the specific forms enumerated above. The enumeration of multiple forms of treatment followed by the generic "or other treatment" also indicates that the word "treatment" is intended to be construed widely.

The Court also identified the purpose of Section of Patents Act from the Statement of Objects and Reasons to align the Patent Law in India with

Agreement on Trade-Related Aspects of Intellectual Property Rights, particularly, Clause 3(a) of Article 27 of TRIPS which enables members to exclude from patent eligibility the following: 'diagnostic, therapeutic and surgical methods for the treatment of humans or animals'. Article 27(3)(a), thus, indicates clearly that the diagnostic method should be for the treatment of humans or animals, but no other limitation or restriction on the scope of the expression "diagnostic methods". The same has been adopted in India.

The Court while ascertaining its position regarding the issue discussed Article 52(4) and Article 53(c) of the Convention on the Grant of European Patents, 1973 (EPC). Interpreting the term 'diagnostic' court under Section 3(i) of the Patents Act, the court noted the Enlarged Board of Appeal's (EBoA) opinion that 'diagnosis' involves four steps, which are:

  1. the examination phase involving the collection of data,
  2. the comparison of these data with standard values,
  3. the finding of any significant deviation, i.e. a symptom, during the comparison, and
  4. the attribution of the deviation to a particular clinical picture, i.e. the deductive medical or veterinary decision phase.

The Court also took into account the March 2023 guideline of the European Patent Office which says:

"The requirement that the final decision phase be included in the independent claim as an essential feature is to be applied only if it is clear from the application/patent as a whole that the inevitable result of the findings leads unambiguously to a particular diagnosis: this will have to be decided by the division on a case-by-case basis."

The Court noted that the language of Section 3(i) of the Patents Act uses the expression "diagnostic...or other treatment of human beings" which points to examining embodiments or use cases to determine 'diagnostic' character of an invention. The Court held that if the process involved does not uncover the pathology then it would not be diagnostic under Section 3(i). The Court also noted the exemption to the standard whereby it gave illustration of testing undertaken not for treatment but for clinical trial which is different from testing carried out to uncover pathology which forms the basis of treatment for the disease.

The Court also answered on the famous debate of Screening and Diagnosis. The Court held that a test if capable of being repeated, by a person skilled in the test, such that it helps them in identifying the disease, disorder or condition then it will a case of diagnosis, no matter it is labelled as screening. Subsequently if a person skilled in the art would not be in a position to diagnose the disease, disorder or condition, as the case may be, on the basis of the process because the process is not designed to diagnose diseases, disorders or conditions, such process, whether labelled as screening or anything else, would not qualify as diagnostic for purposes of Section 3(i).

The Court in the case noted that the claimed invention claims to determine the issue by taking biological sample from a pregnant female subject. Subsequently, the nucleic acid molecule is drawn and cross reference with a Standard reference value and a person, accordingly, determines whether there exists specific chromosomal aberration. The claimed invention was per se incapable of identifying but gave indicators for further testing at a diagnosis. As such, the court held that the claimed invention was related to diagnosis but not diagnostic and, hence, patentable under the Patents Act.

Obiter Dicta

The Court commented on the inconsistency of the Assistant Controller office in granting patent to in vitro processes. The Court recommended that the without compromising the public policy the scope of the expression 'diagnostic' under Section 3(i) should be limited in case of in vitro processes so as to incentivize research in this cutting-edge field.


The Madras High Court meticulously analyzed the appellant's patent application, delving into the nuances of Section 3(i) of the Patents Act. Through a thorough examination, it is clarified that the term "diagnostic or other treatment of human beings" encompasses a broad spectrum, emphasizing the importance of examining embodiments to determine the diagnostic character of an invention. The court's interpretation, drawing insights from international perspectives and guidelines, elucidated that a process must uncover pathology to be considered diagnostic under Section 3(i).

 The decision has provided clarity on the distinction between screening and diagnosis, asserting that a process qualifies as diagnostic if it aids in identifying a disease, disorder, or condition, irrespective of its labeling as screening. The conclusion thus reflects a judicious interpretation of patent law, considering the evolving landscape of diagnostic innovations and emphasizing the need for a nuanced approach in granting patents.

This ruling has brought much-needed clarity to diagnostic procedures. It is thus evident that in terms of evaluation under Section 3(i), there is no distinction between in vitro and in vivo techniques. It is also evident that the term "diagnostic" should not be used to refer to the process of curing a patient's illness. On the other hand, the court has suggested that the legislature take into account changing Section 3(i) to address in vivo procedures. It remains to be seen if the legislature will take this suggestion into account.

Disclaimer: This article was first published in the S&A Law Offices - 'Intellectual Property (IP-Tech)' newsletter in May 2024.

See More Popular Content From

Mondaq uses cookies on this website. By using our website you agree to our use of cookies as set out in our Privacy Policy.

Learn More