Giardia duodenalis and Cryptosporidium spp. are two of the most prominent aetiological agents of waterborne diseases. Therefore, efficient and affordable methodologies for identifying and quantifying these parasites in water are increasingly necessary. USEPA Method 1623.1 is a widely used and validated protocol for detecting these parasites in water samples. It consists of a concentration step, followed by parasite purification and visualization by immunofluorescence microscopy. Although efficient, this method has a high cost particularly due to the immunomagnetic separation (IMS) step, which is most needed with complex and highly contaminated samples. Based on this, the present study aimed to determine whether it is possible to maintain the efficiency of Method 1623.1 while reducing the amount of beads per reaction, using as a matrix the challenge water recommended by the World Health Organization. As for Giardia cysts, a satisfactory recovery efficiency (RE) was obtained using 50% less IMS beads. This was evaluated both with a commercial cyst suspension (56.1% recovery) and an analytical quality assessment (47.5% recovery). Although RE rates obtained for Cryptosporidium parvum did not meet Method 1623.1 criteria in any of the experimental conditions tested, results presented in this paper indicated the relevance of the described adaptations, even in challenge water.

十二指肠贾第鞭毛虫和隐孢子虫属 是两种最突出的水传播疾病病原体。因此，越来越需要用于识别和量化水中这些寄生虫的有效且负担得起的方法。USEPA 方法 1623.1 是一种广泛使用且经过验证的协议，用于检测水样中的这些寄生虫。它包括一个浓缩步骤，然后是寄生虫纯化和免疫荧光显微镜观察。虽然有效，但该方法成本高，特别是由于免疫磁性分离 (IMS) 步骤，这是复杂和高度污染的样品最需要的。基于此，本研究旨在确定是否有可能保持方法 1623.1 的效率，同时减少每次反应的珠子数量，使用世界卫生组织推荐的挑战水作为矩阵。至于贾第鞭毛虫孢囊，使用少 50% 的 IMS 珠子获得了令人满意的回收效率 (RE)。这通过商业包囊悬浮液（56.1% 回收率）和分析质量评估（47.5% 回收率）进行了评估。尽管在任何测试的实验条件下获得的Cryptosporidium parvum 的RE 率都不符合方法 1623.1 的标准，但本文中提供的结果表明了所描述的适应的相关性，即使在挑战水中也是如此。