Reminder that there are many popular novel benzodiazepines out there, including
Etizolam
Flualprazolam
Clonazolam
Flubromazolam
Diclazepam
These are not likely to show up on your typical benzo UDS. If a patient appears to have a sedative-hypnotic appearance but a negative UDS, rest easy in the knowledge that you're still probably right. Although not necessarily new (etizolam, for example, is approved for pharmaceutical use in Japan and Italy), the rise of their abuse has led them to be classified as novel psychoactive substances.
In the US, they are all schedule I drugs, distinct from the schedule IV designation that benzos in clinical use "enjoy." A curious exception is flunitrazepam (Rohypnol, or "roofies"), which is legally treated as schedule I despite actually being schedule IV, due to its noted use to facilitate sexual assault (although frankly, any benzodiazepine would be useful for this goal). Of note, flunitrazepam is also unreliably caught by UDS.