In a pivotal U.S. court decision in November 2013, the diagnostics industry received critical guidance on patent eligibility, particularly for diagnostic method claims. The court invalidated a patent applying the Mayo test, centred on whether method claims pre-empt all future use of a natural phenomenon. The case of Sequenom as the exclusive licensee of a patent for the non-invasive detection of fetal DNA in maternal samples highlighted the fine line in patent eligibility.

The Court's decision, hinging on the Mayo patent eligibility test, scrutinised whether claims in the patent amounted to more than just applying a natural phenomenon. It was determined that the steps outlined in the patent were routine, failing to elevate the claim beyond the natural phenomenon itself. The crucial factor was whether the patent pre-empted all future practical uses of the natural phenomenon. The Court found that Sequenom suggested alternative methods were not commercially viable, thus not mitigating the issue of pre-emption.

This ruling serves as an important lesson for Australian applicants in the US, underscoring that the mere application of known technology to a natural phenomenon does not constitute an inventive or innovative use. The decision underscores the importance of demonstrating that a claimed invention only monopolises some future practical uses of a natural phenomenon, especially in diagnostic patent applications.