If you really wanted to do a scientific study on these myths you really should have access to blood testing. You would need to get accurate THC metabolite levels and urine levels can fluctuate from fluid intake. Home tests also don't give you a number only higher or lower than 50 ng/ml.

What goes on at a lab is no big secret. Most of the time immunoassay tests are conducted using machines (not test strips) and all non negative results are confirmed using GC/MS.