All drug field identification kits are one of two basic types. One is the spot plate kit, where the reagents (chemicals used to detect the presence of a suspected drug) are supplied in bottles. The reagent is added from the bottle a drop at a time into the spot plate -- a plastic or ceramic plate with a depression where the reagent and substance are mixed to complete the test. This type of kit requires the officer to measure the reagents. The other basic kit contains individual premeasured test units sealed in a test container as a single unit. This kit does not require measurement of the reagent by the officer. While the spot plate kit is the least expensive of the two types, it is not as easy to use and creates the possiblility of cross-contamination of reagents. Many drugs yield characteristic colors when they contact specific chemical reagents, and this is the basic principle for field testing. Test precautions and testing procedures are described, and the importance of using a sequential field test to increase the validity of findings is explained. Sequential testing is especially important if a very small amount of the drug is used in a large amount of diluent. Field tests are used only for presumptive identification of a drug. All drugs seized as evidence must be analyzed by a qualified chemist before being submitted in court. The presentation is intended for use in training. Questions based on the material are supplied, along with the answers.