Chagas disease is a public health problem not only in Latin America, but also in other regions, including Spain, due to migration movements. Conventional serological diagnosis requires an invasive sample (plasma or serum) and a well-equipped laboratory. To circumvent those limitations, blood samples dried on filter paper (DBS) or Rapid Diagnostic Test (RDT) could be a practical alternative to reference protocol for serological screening in epidemiological studies. We evaluated the usefulness of dried blood sampling and a rapid diagnostic test (Trypanosoma Detect™) for the detection of antibodies against T. cruzi for their use in community-based screening.

A total of 162 stored paired whole-blood and serum samples from Latin American migrants and 25 negative-control blood samples were included. Diagnosis of chronic Chagas disease was performed in serum according to WHO algorithms. Blood samples were retrospectively collected as dried spots and then analyzed using two different serological techniques, enzyme-linked immunosorbent assay (ELISA) and electrochemiluminescence immunoassay (E-CLIA). Whole-blood samples were also used to evaluate a rapid diagnostic test based on immunochromatography. A better correlation with conventional serum was observed in dried blood elutes using E-CLIA than ELISA (97% vs. 77% sensitivity, respectively). Both assays reported 100% specificity. The median cut-off index values of E-CLIA for dried blood were significantly lower than those for serum (138.1 vs. 243.3, P<0.05). The Trypanosoma Detect™ test presented a sensitivity and specificity of 89.6% and 100%, respectively.

The detection of antibodies against T. cruzi in dried blood samples shows a higher sensitivity when using E-CLIA compared with ELISA. Trypanosoma Detect™ is easier to use but has a lower sensitivity. Hence, we propose a sequential strategy based on performing the rapid test first, and a negative result will be confirmed by DBS-ECLIA for use in community Chagas disease screening programs.

由于移民流动，恰加斯病不仅在拉丁美洲而且在包括西班牙在内的其他地区都是一个公共卫生问题。传统的血清学诊断需要侵入性样本（血浆或血清）和设备齐全的实验室。为了规避这些限制，在滤纸 (DBS) 或快速诊断测试 (RDT) 上干燥的血液样本可能是流行病学研究中血清学筛查参考方案的实用替代方案。我们评估了干血采样和快速诊断测试 (Trypanosoma Detect™) 在检测针对克鲁兹 用于基于社区的筛查。

总共包括 162 份储存的来自拉丁美洲移民的配对全血和血清样本以及 25 份阴性对照血液样本。根据WHO算法在血清中进行慢性恰加斯病的诊断。回顾性收集血样作为干斑，然后使用两种不同的血清学技术进行分析，酶联免疫吸附测定 (ELISA) 和电化学发光免疫测定 (E-CLIA)。全血样本也用于评估基于免疫层析的快速诊断测试。在使用 E-CLIA 的干血洗脱液中观察到与常规血清的相关性比使用 ELISA 更好（灵敏度分别为 97% 和 77%）。两种测定均报告了 100% 的特异性。干血 E-CLIA 的中位截止指数值显着低于血清（138.1 对 243.3，磷<0.05）。Trypanosoma Detect™ 测试的灵敏度和特异性分别为 89.6% 和 100%。

抗体检测 克鲁兹与 ELISA 相比，使用 E-CLIA 时干血样本中的 ELISA 显示出更高的灵敏度。Trypanosoma Detect™ 更易于使用，但灵敏度较低。因此，我们提出了一种基于先进行快速测试的顺序策略，DBS-ECLIA 将确认阴性结果用于社区恰加斯病筛查计划。