Campillo Jérémy T, Louya Frédéric, Bikita Paul, Missamou François, Boussinesq Michel, Pion Sébastien D S, Bertout Sébastien, Chesnais Cédric B
TransVIHMI, Université de Montpellier, Institut de recherche pour le développement (IRD), INSERM Unité 1175, 911 avenue Agropolis, 34000 Montpellier, France.
Programme national de lutte contre l'onchocercose, Direction de l'Épidémiologie et de la lutte contre la maladie, Ministère de la Santé et de la population, Brazzaville, République du Congo.
Med Trop Sante Int. 2023 Mar 23;3(1). doi: 10.48327/mtsi.v3i1.2023.297. eCollection 2023 Mar 31.
BACKGROUND-RATIONALE: The diagnosis of microfilaremia consists in the observation, using a microscope, of microfilariae in a sample of peripheral blood spread on a slide and subsequently stained (the "blood smear technique"). The accurate quantification of microfilaremia is important because the choice of the first intention treatment depends on the patient's microfilaremia: severe adverse events can occur in individuals with high microfilarial densities when treated with ivermectin or diethylcarbamazine, the latter drug being the only one which can definitively cure the infection. However, despite the widespread usage of this technique and its role in guiding clinical management of the patient, estimates of its reliability remain scarce.
We evaluated the reliability (reproducibility and repeatability) of blood smear technique using several sets of 10 -positive slides, randomly selected, and considered the results with regard to regulatory requirements. The slides had been prepared as part of a clinical trial conducted in Sibiti, Republic of Congo, a region where loiasis is endemic.
The estimated and acceptable coefficients of repeatability (NB: the lower, the better) were 13.6% and 16.0%, respectively. The estimated and acceptable coefficients of intermediate reliability (reproducibility) were 15.1% and 22.5%, respectively. The poorest coefficient of intermediate reliability was 19.5% when the tested parameter was related to the technician who performed the readings (10.7% when the reading day was changed). The inter-technician coefficient of variation assessed using 1876 -positive slides was 13.2%. The coefficient of inter-technician variation considered acceptable was estimated at 18.6%. Discussion-Conclusion. All estimated coefficients of variability were lower than the calculated acceptable coefficients suggesting reliability of the technique, although the lack of laboratory references precludes any conclusion on the quality of this diagnosis. It is imperative to implement a quality system and standardization of procedures for the diagnosis of microfilaremia, both in endemic countries and in the rest of the world, where the demand for diagnosis has been increasing for years.
背景 - 理论依据：微丝蚴血症的诊断在于使用显微镜观察涂抹在载玻片上并随后染色的外周血样本中的微丝蚴（“血涂片技术”）。微丝蚴血症的准确量化很重要，因为初始治疗方案的选择取决于患者的微丝蚴血症情况：用伊维菌素或乙胺嗪治疗时，微丝蚴密度高的个体可能会发生严重不良事件，后者是唯一能彻底治愈该感染的药物。然而，尽管该技术广泛应用且在指导患者临床管理中发挥作用，但其可靠性评估仍然较少。
我们使用随机选取的几组10张阳性载玻片评估血涂片技术的可靠性（再现性和重复性），并根据监管要求考虑结果。这些载玻片是在刚果共和国的西比蒂进行的一项临床试验的一部分制备的，该地区是盘尾丝虫病的流行地区。
估计的和可接受的重复性系数（注：越低越好）分别为13.6%和16.0%。估计的和可接受的中等可靠性（再现性）系数分别为15.1%和22.5%。当测试参数与进行读数的技术人员相关时，最差的中等可靠性系数为19.5%（当读数日期改变时为10.7%）。使用1876张阳性载玻片评估的技术人员间变异系数为13.2%。估计的可接受的技术人员间变异系数为18.6%。讨论 - 结论。所有估计的变异系数均低于计算出的可接受系数，表明该技术具有可靠性，尽管缺乏实验室参考标准无法对该诊断的质量得出任何结论。在流行国家和世界其他地区，实施微丝蚴血症诊断的质量体系和程序标准化势在必行，多年来这些地区对诊断的需求一直在增加。
