Department of Parasitology, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden, The Netherlands.
Exp Parasitol. 2013 Oct;135(2):274-82. doi: 10.1016/j.exppara.2013.06.017. Epub 2013 Jul 10.
An earlier reported laboratory assay, performed in The Netherlands, to diagnose Schistosoma infections by detection of the parasite antigen CAA in serum was converted to a more user-friendly format with dry reagents. The improved assay requires less equipment and allows storage and worldwide shipping at ambient temperature. Evaluation of the new assay format was carried out by local staff at Ampath Laboratories, South Africa. The lateral flow (LF) based assay utilized fluorescent ultrasensitive up-converting phosphor (UCP) reporter particles, to be read by a portable reader (UPlink) that was also provided to the laboratory. Over a period of 18 months, about 2000 clinical samples were analyzed prospectively in parallel with a routinely carried out CAA-ELISA. LF test results and ELISA data correlated very well at CAA concentrations above 300 pg/mL serum. At lower concentrations the UCP-LF test indicates a better performance than the ELISA. The UCP-LF strips can be stored as a permanent record as the UCP label does not fade. At the end of the 18 months testing period, LF strips were shipped back to The Netherlands where scan results obtained in South Africa were validated with different UCP scanning equipment including a novel, custom developed, small lightweight UCP strip reader (UCP-Quant), well suited for testing in low resource settings.
The dry format UCP-LF assay was shown to provide a robust and easy to use format for rapid testing of CAA antigen in serum. It performed at least as good as the ELISA with respect to sensitivity and specificity, and was found to be superior with respect to speed and simplicity of use. Worldwide shipping at ambient temperature of the assay reagents, and the availability of small scanners to analyze the CAA UCP-LF strip, are two major steps towards point-of-care (POC) applications in remote and resource poor environments to accurately identify low (30 pg CAA/mL serum; equivalent to about 10 worm pairs) to heavy Schistosoma infections.
荷兰曾报道过一种实验室检测方法，通过检测血清中的寄生虫抗原 CAA 来诊断血吸虫病。该方法经过改良，采用了更便于使用的干式试剂，提高了用户友好度。改良后的检测方法所需设备更少，可在室温下储存和全球运输。南非 Ampath 实验室的当地工作人员对新检测方法进行了评估。该侧流免疫层析法（LF）检测采用了荧光超敏上转换磷（UCP）报告颗粒，由实验室提供的便携式阅读器（UPlink）读取。在 18 个月的时间里，约 2000 份临床样本与常规进行的 CAA-ELISA 平行进行了前瞻性分析。在 CAA 浓度高于 300pg/ml 血清时，LF 检测结果与 ELISA 数据相关性非常好。在较低浓度下，UCP-LF 检测的性能优于 ELISA。UCP-LF 条带可作为永久记录储存，因为 UCP 标记不会褪色。在 18 个月的测试期结束时，LF 条带被寄回荷兰，在那里使用不同的 UCP 扫描设备（包括新型定制的、重量轻的 UCP 条带阅读器（UCP-Quant））验证了南非获得的扫描结果，该阅读器非常适合在资源匮乏的环境中进行检测。
干式 UCP-LF 检测方法证明能够为血清 CAA 抗原的快速检测提供一种可靠、易于使用的方法。在灵敏度和特异性方面，该方法的性能至少与 ELISA 相当，在速度和使用简便性方面则优于 ELISA。检测试剂可在室温下全球运输，且有小型扫描仪可用于分析 CAA-UCP-LF 条带，这是在偏远和资源匮乏环境中实现即时护理（POC）应用的两个重要步骤，可准确识别低（30pg CAA/ml 血清；相当于约 10 对蠕虫）至重度血吸虫病感染。
