Roberts' former law firm, Hogan & Hartson, filed the appeal on behalf of Laboratory Corp., which was found to indirectly infringe a patent for a test that helps predict strokes, heart attacks and dementia, to the tune of an $8 million award. While Roberts didn't explain his recusal, he is likely to have excused himself because of his financial and personal ties to the firm.

The patent claims a method of detecting a vitamin deficiency in a person by using a device to determine the level of an amino acid. The appeal relates to validity with regard to 35 U.S.C. § 101, whether the claimed subject matter is patentable, specifically with regard to the claim term "correlating" related to total homocysteine levels & cobalamin or folate deficiency. This appealed contention is that claimed correlating relates to natural phenomena, which are not patentable.

In February, the Supreme Court had asked the Bush administration to chime in as to whether the case should be heard at the court. The administration recommended that the justices reject the appeal, so it was somewhat of a surprise when the court agreed to take the case on Monday.