OK, this is good.

[Burnt Toast]

Isn't that for lab purposes?

Not necessarily. Instant-type kits that feature additional panels for creatinine and SG are available and increasing in use.

It's a dot screen and I read that if you pass the screen, they stop it there and you're good.

Specimen validity checks are mandated on ALL DOT tests. And ALL DOT tests MUST be sent to the lab for analysis (onsite spot-testing is prohibited, as per DOT regulations).
Even so, the lab will still perform an initial validity and drug check and yes, if the sample passes the initial validity and drug checks, the testing process is over as a 'pass'.