This test usually runs around $40 at most stores. And yes, they are usually kept in glass cabinets w/ locks or behind the counter
As for the percentage, it does not show any information as to how much of a particular substance is in your body. Instead, it will not show a line next to the drug name if the results are positive. If negative, there will be a red/pink line next to the results. The darkness of the line has nothing to do with the results. i.e., if the line is faint for opiates that does not mean that the person is "just sober" or "just used a few days ago". Lids vary in color...it's a manufacturing thing.
As for percentages...these tests are said to be up to 99% valid.
answered 4 years, 6 months ago