Institute for Hygiene and Applied Immunology, Medical University of Vienna, Vienna, Austria.
University Medicine Greifswald, Greifswald, Germany.
J Hosp Infect. 2024 May;147:188-196. doi: 10.1016/j.jhin.2024.01.022. Epub 2024 Feb 17.
A ring trial organized by the Association of Applied Hygiene (VAH) on the bactericidal efficacy of an ethanol-based hand rub was carried out in 17 laboratories according to EN 1500 with the aim of describing the variability of test results and fulfilment of the methodological acceptance criteria.
As a test product, a hand rub based on 80% ethanol (w/w) was tested in comparison with the reference alcohol (60% iso-propanol, v/v) in a crossover design. After pre-washing and contamination following the norm, hands were treated either with the reference alcohol (2 × 3 mL for 2 × 30 s) or the test product (3 mL in 30 s). Post-decontamination values were determined immediately after the rub-in period. Validated neutralizers were used. The arithmetic means of all individual log pre-values, post-values and reduction values were calculated per laboratory. Non-inferiority was assumed when the Hodges-Lehmann 97.5% confidence limit was <0.6 in comparison with the reference. A z-score was calculated to determine the laboratory performance.
Two laboratories did not meet the acceptance criteria and were excluded from the analysis. The bactericidal efficacy of the test product was non-inferior to the reference product in four laboratories and not non-inferior in 11 laboratories. The z-score for the Hodges-Lehmann 97.5% confidence limit indicated a satisfactory performance in all laboratories.
We consider the EN 1500 test method to be robust in terms of the variability of test results. For products of borderline efficacy, the evaluation should be based on more than one test.
应用卫生协会（VAH）组织了一项环试验，按照 EN 1500 用乙醇基洗手液对杀菌功效进行了测试，共有 17 个实验室参与，旨在描述测试结果的可变性和满足方法学验收标准。
试验产品为 80%（w/w）乙醇的洗手液，以参考酒精（60%异丙醇，v/v）为对照，采用交叉设计进行测试。按照标准进行预清洗和污染后，用参考酒精（2×3 毫升，每次 30 秒，共 2 次）或试验产品（3 毫升，30 秒）对手进行处理。揉搓后立即测定消毒后值。使用经过验证的中和剂。每个实验室计算所有个体预值、后值和减少值的算术平均值。当 Hodges-Lehmann 97.5%置信限与参考值相比<0.6 时，认为具有非劣效性。计算 z 分数以确定实验室性能。
有两个实验室未达到验收标准，被排除在分析之外。试验产品的杀菌功效在四个实验室中与参考产品具有非劣效性，而在 11 个实验室中则不具有非劣效性。Hodges-Lehmann 97.5%置信限的 z 分数表明所有实验室的性能均令人满意。
我们认为 EN 1500 测试方法在测试结果的可变性方面是稳健的。对于功效处于边缘的产品，评估应基于不止一次测试。
