You will have a much greater chance of passing a drug test if you know which test(s) you are going to have to take. We also recommend that you test yourself at home using an at-home drug test to see where you fall. PassADrugTest.com offers at-home drug tests for a large variety of toxins, including marijuana, cocaine, methamphetamines, and more. The sooner you begin the detox process, the better off you'll be. That said, there are some instances in which time is of the essence, and you may only have a day or two to prepare. This type of circumstance is exactly why we offer same day cleansers that begin to work within one hour and will keep you passing a drug test for up to five hours.