Is it acceptable to reference limitations from another claim?

Yes, referencing limitations from another claim is generally acceptable. According to MPEP 2173.05(f):

“A claim which makes reference to a preceding claim to define a limitation is an acceptable claim construction which should not necessarily be rejected as improper or confusing under 35 U.S.C. 112(b) or pre-AIA 35 U.S.C. 112, second paragraph.”

This means that patent applicants can refer to limitations in other claims without automatically causing indefiniteness issues.

To learn more:

• claim construction
• claim referencing
• 35 U.S.C. 112(b)
• claim limitations