[BostonCard]

Dilaudid is fairly short acting.  It has a half-life of about 2 hours.
Zolpidem (Ambien) also has a pretty short half-life (2 - 3 hours), though there are delayed release tablets designed to shift the drug's peak dose to later in the night such that levels can be detected later.
Hydrocodone's half-life is about 4 hours.

The others have longer half-lives;
alprazolam (Xanax) is about 12 hours
THC has a half-life of about 4 hours, but the half-life of its primary metabolite (which I think is what is tested for) is 25 - 36 hours

Generally speaking, depending on dose, a drug is detectable through about 5 half-lives, but that to an extent depends on the limits of detection of the test.  It seems likely that at least a couple of the drugs were taken within 12 hours.  Not sure about Xanax or THC.

BC

[BostonCard]

Dilaudid is fairly short acting.  It has a half-life of about 2 hours.
Zolpidem (Ambien) also has a pretty short half-life (2 - 3 hours), though there are delayed release tablets designed to shift the drug's peak dose to later in the night such that levels can be detected later.
Hydrocodone's half-life is about 4 hours.

The others have longer half-lives;
alprazolam (Xanax) is about 12 hours
THC has a half-life of about 4 hours, but the half-life of its primary metabolite (which I think is what is tested for) is 25 - 36 hours

Generally speaking, depending on dose, a drug is detectable through about 5 half-lives, but that to an extent depends on the limits of detection of the test.  It seems likely that at least a couple of the drugs were taken within 12 hours.  Not sure about Xanax or THC.

BC