Opium derivatives are substances synthesized from morphine, codeine, or thebaine, such as Heroin (from morphine) and Oxycodone (from thebaine).

Suboxone most probably tests positive for buprenorphine, a synthetic derivative of thebaine. Thebaine is one of the alkaloids found in opium. I suppose it could also show positive for thebaine.

reduction of thebaine

Thebaine is used to create other more effective opiate narcotic agonists and antagonists such as Oxycodone,Buprenorphine,Naloxone and a few others.

A benzyltetrahydroisoquinoline is an isoquinoline which is used in the production of analgesics such as morphine, codeine and thebaine.