“…For the retrospective studies, 15 reported that injured patients were routinely tested [35, 37, 39, 42, 68, 69, 72, 77–79, 84, 87, 89, 93, 97, 107] and 9 reported non‐routine approaches (e.g., at the discretion of clinicians or site‐specific policies) [56, 60, 61, 80, 85, 90, 91, 95]. Of the 15 consent‐based studies, 10 used consecutive sampling methods where consent was sought from all patients who met the study's eligibility criteria [31, 33, 36, 52, 53, 57, 62, 105, 111, 112], 3 used probability sampling (e.g., approached consecutive arrivals during set shifts that were representative of various times and days of the week) [103, 104, 113] and 2 obtained retrospective consent after using a waiver of consent to collect samples [108, 109]. Testing or recruitment approach was reported in 18 (49%) studies that examined drugs other than alcohol.…”