Internal quality control: Moving average algorithms outperform Westgard rules

IntroductionInternal quality control (IQC) is traditionally interpreted against predefined control limits using multi-rules or ‘Westgard rules’. These include the commonly used 1:3s and 2:2s rules. Either individually or in combination, these rules have limited sensitivity for detection of systematic errors. In this proof-of-concept study, we directly compare the performance of three moving average algorithms with Westgard rules for detection of systematic error.MethodsIn this simulation study, ‘error-free’ IQC data (control case) was generated. Westgard rules (1:3s and 2:2s) and three moving average algorithms (simple moving average (SMA), weighted moving average (WMA), exponentially weighted moving average (EWMA); all using ±3SD as control limits) were applied to examine the false positive rates. Following this, systematic errors were introduced to the baseline IQC data to evaluate the probability of error detection and average number of episodes for error detection (ANEed).ResultsFrom the power function graphs, in comparison to Westgard rules, all three moving average algorithms showed better probability of error detection. Additionally, they also had lower ANEed compared to Westgard rules. False positive rates were comparable between the moving average algorithms and Westgard rules (all <0.5%). The performance of the SMA algorithm was comparable to the weighted algorithms forms (i.e. WMA and EWMA).ConclusionApplication of an SMA algorithm on IQC data improves systematic error detection compared to Westgard rules. Application of SMA algorithms can simplify laboratories IQC strategy.     

卫生检验与检疫专业病毒学检验实验教学改革探索

“病毒学检验实验”是卫生检验与检疫专业必修的专业实践课，它注重培养学生在病毒学检验中的实践能力和解决问题能力。因此，本研究结合当前公共卫生需要，以提高学生实践综合能力为目标，进行实验教学改革与探索。本文对病毒学检验实验课程体系中的教学方法和手段、实验考核方法进行改革探索，提出研究型、实战式、案例式病毒学检验实验教学模式；受新冠疫情影响，采用线上线下混合式教学，并在原有实验基础上，新增虚拟仿真实验，打破时空限制，帮助学生掌握实验技能。此外，采用综合实验考核方案，构建适合于卫生检验与检疫专业病毒学检验的实验教学体系。     

Cost-effectiveness of maternal immunization against neonatal invasive Group B Streptococcus in the Netherlands

BackgroundNeonatal invasive Group B Streptococcus (GBS) infection causes considerable disease burden in the Netherlands. Intrapartum antibiotic prophylaxis (IAP) prevents early-onset disease (EOD), but has no effect on late-onset disease (LOD). A potential maternal GBS vaccine could prevent both EOD and LOD by conferring immunity in neonates.ObjectiveExplore under which circumstances maternal vaccination against GBS would be cost-effective as an addition to, or replacement for the current risk factor-based IAP prevention strategy in the Netherlands.MethodsWe assessed the maximum cost-effective price per dose of a trivalent (serotypes Ia, Ib, and III) and hexavalent (additional serotypes II, IV, and V) GBS vaccine in addition to, or as a replacement for IAP. To project the prevented costs and disease burden, a decision tree model was developed to reflect neonatal GBS disease and long-term health outcomes among a cohort based on 169,836 live births in the Netherlands in 2017.ResultsUnder base-case conditions, maternal immunization with a trivalent vaccine would gain 186 QALYs and prevent more than €3.1 million in health care costs when implemented in addition to IAP. Immunization implemented as a replacement for IAP would gain 88 QALYs compared to the current prevention strategy, prevent €1.5 million in health care costs, and avoid potentially ~ 30,000 IAP administrations. The base-case results correspond to a maximum price of €58 per dose (vaccine + administration costs; using a threshold of €20,000/QALY). Expanding the serotype coverage to a hexavalent vaccine would only have a limited additional impact on the cost-effectiveness in the Netherlands.ConclusionsA maternal GBS vaccine could be cost-effective when implemented in addition to the current risk factor-based IAP prevention strategy in the Netherlands. Discontinuation of IAP would save costs and prevent antibiotic use, however, is projected to lead to a lower health gain compared to vaccination in addition to IAP.