Text Box 3.

UDT LC-MS/MS Results Examined

LC-MS/MS Result	Definition
Prescribed opioid non-detection	No detectable (detection threshold = 20 ng/ml) amount of any opioid prescribed for the 90 days before the UDT. We excluded UDTs for patients for whom fentanyl, tramadol, or meperidine (not detected by LC-MS/MS) were the only opioids prescribed for the prior 90 days.
THC (marijuana)
Non-prescribed opioid	Opioid for which patient had no prescription covering the 90 days prior to the UDT
Illicit drug	Non-prescribed amphetamine, methamphetamine, cocaine, PCP, MDMA (ecstasy), or 6-AM (heroin metabolite). We considered UDTs positive for illicit amphetamine only for patients with no prescriptions in the previous 90 days for stimulant medications detected as amphetamines.
Non-prescribed benzodiazepine	Benzodiazepine for which patient had no prescription covering the 90 days prior to the UDT
Dilute sample

6-AM 6-acetylmorphine; LC-MS/MS liquid chromatography-tandem mass spectrometry; MDMA 3,4-methylenedioxymethamphetamine; PCP phencyclidine; THC tetrahydrocannabinol

Note: When examining opioid non-detection or substance presence, we excluded tests in which opioid or substance absence could not be confirmed due to dilute sample.