Claim 19 was directed to a kit containing instructions for performing the inventors' method, as well as a list of laboratory reagents designed to perform the method described in claim 1. The US PTO allowed the first 18 claims, but rejected claim 19 because it was anticipated by prior art. Because one of the listed reagents was a buffer, and kits containing printed instructions and a buffer were previously known, the court argued that claim 19 merely teaches a new use for an existing product; so although Ngai and Lin can claim the new use as a method, they cannot claim the kit just because they add new instructions to an old reagent. The inventors argued that the addition of new printed matter to a known product makes the product patentable, relying on the language of a previous case (In re Gulack, Federal Circuit 1983), which states that the difference between an invention and the prior art cited against it cannot be ignored merely because those differences reside in the content of the printed matter.
However, the US PTO relied on a different part of the Gulack case, which raises the crucial question of whether there is any new and unobvious functional relationship between the printed matter and the content of the invention.
