Research how urine & some other drug tests actually work

I am working on developing a new product which will detect the presence of I want to know how a typical drugs urine test actually works. Traditional tests indicate which drug is present in the urine and sometimes indicate which drug specifically is present, if any. I only want to develop a product that gives a positive or negative response to the presence of any drugs. I am assuming the paper is coated with a substance. I need a report providing comprehensive answers to the questions below: Which drugs are tested for in your typical urine test? How does the test actually work? What is the sample size of liquid need to complete the test. Which chemical reaction takes place on the paper? Which chemicals on the paper react with which drugs? How does the colour change on the paper test work? Would the paper be able to provide an accurate response from a liquid other than urine that had a drug in it. For example if I poured a sample directly from a beer that had a roofie in it, would it give a positive response? Also what is the potential harm caused if the potential chemical was ingested . For example if I did a urine test and swallowed the paper? I would appreciate any additional links, comments, diagrams, infographics etc that can help me get to the bottom of this. Also any information on similar but slightly different test would also be extremely helpful. Regards George