The long term objective is to develop a very sensitive pocket size fiber-optic fluoro-immunoassay (FFIA) system for the detection of drugs of abuse. This detection would be either of individual drugs or simultaneously of one or more drugs in a panel of up to 50 drugs. This detection would take less than 30 seconds. Simultaneous detection would be done on a single specimen without any sample preparation or sample volume measurement. There are two specific aims. The first is to determine the feasibility of ORD's fiber optic fluoro-immunoassay (FFIA) method for the detection of cannabinoids. The proposed sensitivity goal is 10 ng/ml of the THC urinary metabolite. Although an assay is proposed for urinary metabolites ORD's method (unlike others) has the potential for measuring the free drug directly in a drop of whole blood without any separation steps. The second specific aim is to modify the FFIA instrument for an investigation into optimizing fiber area to allow for the maximum number of drugs that can be detected simultaneously.