5. Baseline screening for benzodiazepines in trial participants.

Trial	Required period free of benzodiazepines before inclusion	Baseline screening for benzodiazepines	Screening method and detection level	Negative testing at baseline an inclusion criterion	Proportion testing positive for benzodiazepines at baseline
Amodio 1997	2 weeks	Yes	Blood Emit‐dau technique, Dupont Detection limit 0.3 μg/mL diazepam	No	0%
Barbaro 1998	4 days	Yes	Blood Thin‐layer chromatography: Detection limit > 11 mg/L	No	1.9%
Cadranel 1995	Not reported	Yes	Blood and urine Thin‐layer chromatography: Detection limit > 11 mg/L	No	21.4%
Dursun 2003	3 days	No	Not reported	Not reported	Not reported
Giger‐Mateeva 1999	3 months	Yes	Urine Abbott TDx/TDxFLx immunoassay Detection limit < 200 ng/mL	No	0%
Gooday 1995	1 month	No	Not reported	Not reported	Not reported
Gyr 1996	Yes, but length not specified	Yes	Blood and urine Abbott TDx immunoassay Detection limits: blood 10 ng/mL 100 ng/mL, urine < 200 ng/mL Post‐hoc analysis High‐pressure liquid chromatography Detection limits: blood < 50 ng/mL, urine 10 ng/mL to 100 ng/mL	No	8.2% on screening tests Flumazenil 11%; placebo 5% 12/49 samples for more sensitive testing lost
Hermant 1991	Not reported	Yes	Not reported	Yes	0%
Klotz 1989	Not reported	No	Not reported	Not reported	Not reported
Lacetti 2000	2 weeks	Yes	Urine Roche KIMS immuno‐enzymatic assay Detection limit: not specified Post‐hoc analysis High‐pressure liquid chromatography Detection limit: not specified	Yes	0%
Li 2009	Not reported	No	Not reported	N/A	N/A
Pomier‐Layrargues 1994	3 days	Yes	Blood Abbott TDx immunoassay Detection limit 12 ng/mL Post‐hoc analysis Gas chromatography‐mass spectroscopy Detection limit: 1 ng/mL	No	19%
Van der Rijt 1995	Recent	Yes	Blood High‐pressure liquid chromatography Detection limit: not specified	Yes	0%
Zhu 1998	7 days	No	Not reported	Not reported	Not reported