Some things to keep in mind in the future:

- Even though their cutoff thresholds numerically differ, a 50 ng assay is functionally equivalent to the 15 ng GC/MS. Their cutoff thresholds numerically differ is because the assay recognizes all 31 metabolite concentrations combined, while the GC/MS recognizes only one metabolite concentration.

THC enters the body in its ingested form and exits the body as 31 different metabolite concentrations. The most prevalent of these concentrations is THC-COOH.

In order to test negative on the assay, the whole combination of the 31 metabolite concentrations must register below 50 ng.

In order to test negative on the GC/MS, only that one metabolite concentration (the THC-COOH metabolite concentration) must register below 15 ng.
The cutoff is set numerically lower to make the two types of tests functionally equivalent.



- There is no meaning attributed to the intensity of a line on a home test or any other instant assay. Even synthetic urines (which contain no drug metabolites at all) can produce a faint line on an assay.

A faint line is still a negative. Even if an untrained tech were to misinterpret a faint line as a "non-negative", and sent the sample to the GC/MS for confirmation, the sample would still come back as a negative.