Is hand surface coverage a good measure of hand hygiene effectiveness

Background: Effective hand hygiene (HH) is fundamental to the prevention of healthcare-associated infections. One of the commonly used ways for assessing the effectiveness of HH procedure is measuring the extent of hand surface coverage with alcohol-based handrub (ABHR). Methods: In this Latin square design study, handrubbing with ABHR was performed seven times by each of the 35 volunteers. Volunteers’ hands were contaminated with the Escherichia coli K12 strain as per EN 1500 guidelines. Glove juice samples were collected from their hands before and after each ABHR application and surface coverage was measured using Hand-in-Scan® scanner. The relationship between the bacterial log10 reduction and percent surface coverage was analysed using Spearman’s Rank Order Correlation and simple linear regression. Results: Surface coverage ranged from 49.38% to 100% (N= 208, Mdn: 97,33%, IQR= 83.52 – 99.93), while the E. coli reduction ranged from 0.96 to 5.92 log10 (N= 221, M: 3.07, SD= 0.94). The Spearman’s Rank Order Correlation results showed no significant correlation between percent hand surface coverage and E. coli log10 reduction [r= -0.009, n= 198, p= 0.905]. The lack of correlation was further confirmed by the linear regression. Conclusions: These findings suggest that the rate of surface coverage does not correlate with reduction in bacterial load on hands following HH. Although visual feedback on surface coverage can be a good approach to teaching the correct HH technique, these findings suggest that surface coverage alone is not a reliable measure of HH effectiveness.