The medical diagnostics industry is making one more push to protect its technology from Section 101 patent eligibility challenges, but seemed to hit a familiar brick wall Thursday at the U.S. Court of Appeals for the Federal Circuit.

Athena Diagnostics, Oxford University and the Max Planck Institute accuse the Mayo Clinic of infringing their 7,267,820 patent on a technique for diagnosing the neuromuscular disease myasthenia gravis. U.S. District Judge Indira Talwani of Massachusetts ruled the patent ineligible on the ground that Athena, a subsidiary of Quest Diagnostics Inc., had patented a law of nature.