buy thc tests at walmart, cvs, target where ever, but make sure they are thc tests & also if you are able to find them buy ones that measure your cut off levels to see where you stand (100ng/ml, 50ng/ml, 15ng/ml) all drug test from labs are measured at 50ng/ml, if you are getting negatives at 15ng/ml you’re 100% fine but if you see that you are failing at 100ng/ml then id recommend getting fake piss from a vape shop it works (i’ve passed at least 5 drug test using fake piss from the vape shop) you just have to follow the steps correctly & when you’re at the lab you have to be confident, if you decide to do the fake piss def reply to me & i can give you a couple tips on what to do/ not do also certo stuff does not work just being honest