Hand rub dose needed for a single disinfection varies according to product: A bias in benchmarking using indirect hand hygiene indicator

Background: The 3 ml volume currently used as the hand hygiene (HH) measure has been explored as the pertinent dose for an indirect indicator of HH compliance. A multicenter study was conducted in order to ascertain the required dose using different products. Method: The average contact duration before drying was measured and compared with references. Effective hand coverage had to include the whole hand and the wrist. Two durations were chosen as points of reference: 30 s, as given by guidelines, and the duration validated by the European standard EN 1500. Each product was to be tested, using standardized procedures, by three nosocomial infection prevention teams, for three different doses (3, 2 and 1.5 ml). Results: Data from 27 products and 1706 tests were analyzed. Depending on the product, the dose needed to ensure a 30-s contact duration in 75% of tests ranging from 2 ml to more than 3 ml, and to ensure a contact duration exceeding the EN 1500 times in 75% of tests ranging from 1.5 ml to more than 3 ml. The aftermath interpretation is the following: if different products are used, the volume utilized does not give an unbiased estimation of the HH compliance. Other compliance evaluation methods remain necessary for efficient benchmarking.