In one of the most anticipated IP cases on this year’s docket, the U.S. Supreme Court on Tuesday held that a medical process for testing blood was not eligible for patent protection because the patent claims only recited laws of nature.

In Mayo v. Prometheus Laboratories Inc., the process claimed in the Prometheus patents recited a relationship between concentrations of metabolites of a drug and the likelihood that the drug dosage would be ineffective or would cause harm.

The Federal Circuit had found that administering the drug and determining the metabolite levels were transformative steps, in that the human body was transformed by the taking of the drug and the blood for measuring the metabolites was transformed when taken from the body. The patent claims thus met the “machine or transformation” test for deciding patent-eligible subject matter, the appellate court held.

The Supreme Court unanimously reversed the Federal Circuit, holding the claims recited correlations that were laws of nature and were “drafting efforts designed to monopolize the correlations.”

Although it takes human action to administer the drug, Justice Stephen G. Breyer found that the relationship between the administered drug and the level of metabolites “exists in principle apart from any human action” and is an entirely natural process. The question, Breyer said, was whether the claims add “more” to allow the processes described to qualify as processes that apply a law of nature.

Applying the New Test

What are these elements or “additional features” that must be added to a process employing a natural law? Two things that are not sufficient are 1) limiting the use of the law of nature, abstract idea, or natural phenomena to a particular technological environment or 2) adding steps that are “purely conventional or obvious,” well understood, routine, or conventional activity already engaged in by the scientific community. Conventional steps with a “high level of generality” in combination with laws of nature are not patent-eligible. Highly general language covering all processes that make use of the law of nature do not recite patent-eligible subject matter.

What are probably sufficient additional elements?

  • Use of one or more unconventional steps that confine the claims to a “particular useful application of the law of nature, abstract idea or natural phenomenon”
  • A new combination of steps in a process, even when all the constituents of the combination are well known and in common use, so that when viewed as a whole, the combination adds something beyond the individual steps, or the combination is not obvious, not already in use, or purely conventional
  • Individual steps that recite a transformation may make a process claim patent-eligible

For more information, contact Scott D. Marty at 678-420-9408 or

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