Presumptive Drug Test Kits can be an important part of your internal investigation. These tests are used to determine whether the substance found is the suspected drug. In general, to use these drug test kits a small amount of the substance is placed in the NIK polyethylene pouch. The pouch holds one or more ampules containing reagents. Once the substance is sealed in the pouch it is squeezed per included directions to break the ampule(s) and expose the reagents to the substance. The drug test result is considered positive if it changes to the specified color when mixed.