It's go or no-go, above or below the limit. It's quick. Any policeman could do it at the roadside. For that matter, any skilled person could. This kit is designed to collect a sample, which goes into the vial. It's sent off to a forensic laboratory. They do the analysis there, and then you get a quantitative measure of drugs in the body.
On September 27th, 2017. See this statement in context.