I have personally only had one test come back positive out of about 50. That was over a year ago test for a friend, and I tested everything they got. I've seen far more adulterated with PMA (the stuff that gets your teeth grinding and sweaty).

These are supposed to be urine tests, so make sure you keep the concentration in the range needed. The ratio is 1:500 by weight. So 10 mg prod to 5g water (5g ~ 1 teaspoon). So enough to cover your pinky nail. I use a scale. For the product make sure it is crushed finely and a mix of everything in the bag. I usally take some samples of rock, shake, etc. and then grind them finely with a spoon in a glass. Mix it up. I have these small test tubes where I know the 10 mg demarcation so I can do them pretty quickly now. Reat the testing strip for the amount of time and set your phone.

If you doubt your testing, do a test known to be negative to make sure you are getting the right amount of product, water, and time. The strips do go bad, so look for the expiration date, and the way most people store them they go bad way before that (cool, DRY place - not the refridgerator).

Happy Testing.

happy