How common and how acceptable is the use of ordered lists and the phrase "and combinations thereof" as the last component of a Markush Group claim?

Question

Admittedly this is squeezing two questions into one, but they're both directly about Markush Group claim construction. From all I've read, the structure of this type always uses "selected from the group consisting of (A, B, and C or A, B, or C)" and it is always "consisting of" not "comprising." (In fact that last part is explicitly stated in MPEP 2173.05(h) Alternative Limitations [R-11.2013] - I.MARKUSH GROUPS.)

Question, part 1: I have assumed it's just as acceptable to list the components in an ordered list form such as a), b), c), as to list them linearly in a statement. True? It seems so, from MPEP's statement "a list of alternatively useable species regardless of format."

Question, part 2: I have read (from someone who asserts he's used it repeatedly with success) that using "and combinations thereof" as the last component of the Markush Group is the best solution to eliminating any uncertainty about "A, B, C with mutual exclusion" vs. "A, B, C individually OR in any combination." True?

Answer 1

To Part 1: Yes it is acceptable to add an ordered list as long as the claim is written clearly, and the claim follows the rules for claim writing (so no ‘a. b. c.’ that would add periods within the claim and is a no-no). It is fairly common to present ordered lists in method claims, and MPEP 2173.05(h) states that for Markush groups “Alternative expressions are permitted if they present no uncertainty or ambiguity with respect to the question of scope or clarity of the claims”. That would be your support for adding an ordered list.

To Part 2: Yes, ‘combinations thereof’ or ‘mixtures thereof’ should be both in the Markush Group claim as well as described in the specification if you want the claim to expressly cover combinations. If the specification doesn’t disclose or teach towards combinations, the claim cannot be construed to include combinations after the fact, as the Federal Circuit Court found in Abbott Labs. v. Baxter Pharm. Prods., Inc., 334 F.3d 1274, 1280-81 (Fed. Cir. 2003).

But, if the spec does include discuss combinations or mixtures then a Markush group claim without the expressly written ‘combinations thereof’ can be construed as including combinations – BUT best practices would be to include it expressly in the claim before an infringement lawsuit goes to court. The relevant case law is Multilayer Stretch Cling Film Holdings, Inc. v. Berry Plastics Corp., Nos. 2015-1420, -1477 (Fed. Cir. Aug. 4, 2016) at 21.