Infringement Adequately Shown Without Direct Measure of the Claimed Element

In Re Gabapentin Patent Litigation, [2006-1572] (September 21, 2007)[LOURIE, Linn, Moore] The Federal Circuit reversed sum may judgment of non-infringement of U.S. Patent No. 6,054,482 because the district court erred in determining that there were no genuine issues of material fact, but affirmed the district court's claim construction.
SIGNIFICANCE: Federal Circuit approves indirect proof of a claim limitation.
BRIEF: The parties disputed whether the patentee's use of pH testing to determine the accused product met the limitation of less than 20 ppm acidic chloride. The defendant's focused on the lack of precision of the test +/- 5%. The Federal Circuit found that the test of at least one sample did meet the claim limitation, and that the defendants had waived their objection whether the test was a proper measure of the acidic chloride content.