Sure. Theres been several instances where a person had tested positive beyond 30 days. The 30-day rule does not apply to everyone by any means. Its not all uncommon for longtime daily users to test positive for 60 days or more.

In fact, we had a couple of individuals who tested positive at 100+ days (the most recent being MollylovesMary, who has a couple of threads posted on this page of the forum).