Samples do not get sent to the GC/MS because theyre diluted. Only samples that tested positive for THC (or any other drug) on the assay screen get sent to the GC/MS for confirmation.

The GC/MS is not a more sensitive test than the assay - its just more accurate. Even though the cutoff thresholds are numerically different, a 50 ng assay screen is functionally equivalent to the 15 ng GC/MS. The cutoff numbers are different because the assay recognizes the composite of all 31 metabolite concentrations while the GC/MS only recognizes one metabolite concentration: THC-COOH.

Detox products are a big scam to exploit unfortunate victims of the so-called "war on drugs" and seperating them from their cash. When they do work, they "work" because of the dilution factor. You could spend upwards to $200 on a magic elixir and accomplish nothing different that what is accomplished using vitamin B2 (yes, B2) and water.

Forget the snake oil products and read the Dilution sticky thread.