LMAO, feel free to contact the labs posted here as well as the FDA's Center for Veterinary Medicine, & run your false positive theory by them. No one is stopping you from having an NMR done, or an IR graph to verify. Knock yourself out.
The only fair way to measure it would be to individually analyze the raw ingredients individually that NF uses.
No, it's not possible, unless you were on site at the facility in question to gather the samples from their bulk raw ingredients pre manufacture - which for the most part in this case would be their fish meal, and krill meal.
I would love nothing more than to have someone prove these labs wrong.