Specific drug test results cannot be guaranteed. There are different types of tests that look for different types of cannabinoids. For instance, some tests search only for THC while others search for all cannabinoids. The safest way to ensure that no THC will show up on a drug test is to use products that do not contain THC. Make sure you always purchase CBD oil from reputable sellers. Some factors to consider are;does the product being used have other cannabinoids in it? How much of it is being consumed and how often? Any medical factors, such as medication begin taken, liver and/or kidney disease that can affect metabolism; and the metabolism of the individual.