Definiteness, like claim construction, should be assessed from the viewpoint of a person of ordinary skill in the art at the time the patent was filed, and it should be considered in view of the patent’s specification and prosecution history.
It seems to me that if a POSITA could understand the bounds of the term regardless of the overlap, they are not indefinite.11 Defendants also point out that a particular agent might operate as a membrane stabilizer or cell lysis inhibitor under certain conditions but not others.
During prosecution of the ʼ277 patent, the examiner rejected certain claims as anticipated by Lo, stating, “Lo et al. teach collecting maternal blood into a tube comprising EDTA (i.e. an agent that inhibits cell lysis.”13 The patentee responded in pertinent part:
However, I agree with Plaintiff that the prosecution history indicates that the word “fetal” was added to the claims not to specify that the fetal DNA needs to be isolated from the maternal DNA, but rather to indicate that the analysis is performed on a sample obtained from a pregnant female that contains fetal DNA.16 also note that my recommendation is consistent with the construction adopted by Judge Albright in the Ravgen v. Labcorp case.17 While his construction is, of course, not binding on the Court, I do agree with his conclusion.
Instead, the prosecution history reflects that the phrase “non-cellular fraction” was added to 18 Plaintiff argued that no construction was necessary but offered an alternative proposal in case the Court construed the term.