Williamson 1999.

Methods	Randomised clinical trial.
Participants	Country: United Kingdom. Sample size: 28. Post‐randomisation drop‐out(s): 3 (10.7%). Revised sample size: 25. Females: 13 (46.4%). Mean age: 49 years. Piggyback: not stated. Conventional: not stated. Cadaveric donor: not stated. Live donor: not stated. Inclusion criteria: 1. Adult patients with liver disease or undergoing liver transplantation (only liver transplantation patients were included in this review).
Interventions	The patients were randomised to the following groups. Group 1: intervention (n = 12). Further details: solvent detergent treated fresh frozen plasma. Group 2: control (n = 13). Further details: standard fresh frozen plasma.
Outcomes	The outcomes reported were blood transfusion requirements.
Notes	Attempts were made to contact the author in September 2011. Reason for post‐randomisation drop‐out(s): protocol violation (3).
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Assignment was accomplished by the opening of a previously allocated, computer‐generated, randomly numbered envelope".
Allocation concealment (selection bias)	Unclear risk	Quote: "Assignment was accomplished by the opening of a previously allocated, computer‐generated, randomly numbered envelope". Comment: Further details were not available.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Comment: This information was not available.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Comment: This information was not available.
Incomplete outcome data (attrition bias) All outcomes	High risk	Comment: There were post‐randomisation drop‐outs.
Selective reporting (reporting bias)	High risk	Comment: Important outcomes were not reported.
Vested interest bias	High risk	Quote: "Supported in part by Octapharma AG (Vienna, Austria)".