1. butterfly is undergoing a screening test, not an impairment test, which is what the article you're quoting from is demonstrating.

2. Using the part of your quote you should have noticed. "however, they can be sensitive to other metabolites as well." A drug screening test isn't just looking for THC as an impairment test does. There are at least three separate cannabinoids that will stay in arterial fat deposits for up to 30 days.

3. If they are your good friends you should know the difference.

peace