Laboratory Corp. of America Holdings v. Metabolite Laboratories, Inc.

Background

A company that owned a patent claimed a method for detecting vitamin B deficiencies by checking for elevated homocysteine levels. A large medical testing company (LabCorp) stopped paying royalties for a different lab test and was sued. Lower courts found the patent valid, assessed damages, and enjoined LabCorp from performing homocysteine-only tests that would lead doctors to diagnose deficiencies.

Reasoning

The narrow question was whether a patent that essentially tells a doctor to “test for homocysteine and correlate the result with vitamin deficiency” improperly claims a natural medical relationship. The Supreme Court dismissed its review as improvidently granted and gave no ruling on that legal question. Justice Breyer, joined by Justices Stevens and Souter, wrote a dissent arguing the Court should have decided the issue and explaining why he believed the claim was an unpatentable natural phenomenon.

Real world impact

Because the Court declined to decide the merits, the lower-court judgment — including the damages award and the injunction limiting homocysteine-only tests — remains in effect. The dissent warned that leaving the issue unresolved could affect how doctors and labs use basic medical correlations, increase licensing and legal costs, and create uncertainty about patents on medical discoveries.

Dissents or concurrances

Justice Breyer dissented, arguing the patent improperly monopolizes a natural relationship and urging the Court to resolve the issue to protect medical practice and clarify the law. The Chief Justice did not participate.