Hajipour 2006.

Methods	Cluster randomised controlled trial Generation of random number sequence: random number table Allocation concealment: no details given Blinding: microbiologist was blinded A priori sample calculations: no Antisepsis protocol: yes Withdrawals: no details given Intention‐to‐treat analysis: no Clear inclusion or exclusion criteria: no
Participants	4 surgeons working in a trauma surgery Baseline comparability: surgeon's grade, order of patient on the operating list, duration of surgery
Interventions	Group 1 ‐ 3 min scrub using aqueous chlorhexidine gluconate Group 2 ‐ 3 min application of 0.5% chlorhexidine gluconate in 70% alcohol All surgeons washed with chlorhexidine (no further detail) for 5 min for first procedure with thorough cleaning under fingernails.
Outcomes	Outcome measure: CFUs on participants' hands Method of testing: finger press testing with agar plates Timing of testing: at the end of the surgical procedure
Notes	The 4 surgeons, who were not blinded, were randomised once and tested 53 times
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Orthopaedic surgeons were allocated to one of two different hand‐washing protocols using a randomisation table"   Comment: evidence of random sequence generation, therefore judged as low risk
Allocation concealment (selection bias)	Unclear risk	Quote: "[T]he surgeon was randomised to wash for 5 min with either chlorhexidine or alcohol gel"   Comment: no evidence that there was an attempt at allocation concealment
Blinding (performance bias and detection bias) All outcomes ‐ Blinding participants	Unclear risk	Quote: "The hand‐washing protocol dictated that all surgeons should wash for 5 min with chlorhexidine for their first case with thorough cleaning under the fingernails. Thereafter, the surgeon was randomised to wash for 5 min with either the chlorhexidine or alcohol gel. Alcohol was allowed to dry on the hands prior to double gloving".   Comment: no evidence that participants or personnel were blinded to intervention
Blinding (performance bias and detection bias) All outcomes ‐ Blinding care givers	Unclear risk	Quote: "The hand‐washing protocol dictated that all surgeons should wash for 5 min with chlorhexidine for their first case with thorough cleaning under the fingernails. Thereafter, the surgeon was randomised to wash for 5 min with either the chlorhexidine or alcohol gel. Alcohol was allowed to dry on the hands prior to double gloving".   Comment: no evidence that participants or personnel were blinded to intervention
Blinding (performance bias and detection bias) All outcomes ‐ Blinding outcome assessors	Low risk	Quote: "The number of bacterial colonies present after 24 h and 48 h of incubation were recorded for each agar plate by a microbiologist blinded to the washing protocol used"   Comment: adequate blinding of assessment outcome
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: "Overall, 41 procedures and 82 episodes of handwashings were included in the study. Two episodes were discarded due to contamination at the time of glove removal. There was no incidence of outer glove perforation during this study"   Comment: good evidence to suggest losses to follow‐up were accounted for and there was minimal effect of attrition bias
Selective reporting (reporting bias)	Low risk	No direct quotes, but the assessment variable of bacterial colonisation after different methods of handwashing (which was outlined in the methodology) is accounted for in the results.
Other bias	Unclear risk	This appears to be a clustered randomised trial; it does not seem that clustering was taken into account in the analysis.