Abstract：
OBJECTIVE: The current diagnostic methods for leptospirosis diagnosis are technically complex and expensive, with limited applicability to specialized laboratories. Furthermore, they lack diagnostic accuracy in the acute stage of the disease, which coincides with a period when antibiotics are highly effective. New simple and accurate tests are mandatory to decentralize and improve diagnosis. Here, we introduced a new lateral flow immunoassay (Lepto-LF) for human leptospirosis.
METHODS: We conducted a double-blinded assay using 104 serum samples from patients with confirmed or discarded diagnosis for leptospirosis. The diagnostic performance of Lepto-LF was estimated across different ranges of days from onset of symptoms (dpo), considering the diagnostic algorithm as reference standard. Additionally, it was compared with the screening methods enzyme-linked immunosorbent assay (IgM-ELISA) and the slide agglutination test using temperature-resistant antigen (SATR).
RESULTS: Lepto-LF exhibited perfect diagnostic performance with a Youden´s index J = 1 from 6 dpo in the acute phase. IgM-ELISA gave slightly lower accuracy with J = 0.91 and 95.5% of both sensitivity and specificity; while SATR showed a markedly inferior yield (J = 0.41, sensitivity = 95.5%, specificity = 45.5%). The performances remained consistent in the convalescence phase of the disease (> 10 dpo).
CONCLUSIONS: Lepto-LF was found to be a reliable test for simple, rapid and early diagnosis of leptospirosis, resulting a promising tool for decentralizing leptospirosis diagnosis and enabling timely treatment of patients. In addition, Lepto-LF may be employed as confirmatory test, especially in remote areas and vulnerable contexts where the standard MAT is not available.
METHODS: We conducted a double-blinded assay using 104 serum samples from patients with confirmed or discarded diagnosis for leptospirosis. The diagnostic performance of Lepto-LF was estimated across different ranges of days from onset of symptoms (dpo), considering the diagnostic algorithm as reference standard. Additionally, it was compared with the screening methods enzyme-linked immunosorbent assay (IgM-ELISA) and the slide agglutination test using temperature-resistant antigen (SATR).
RESULTS: Lepto-LF exhibited perfect diagnostic performance with a Youden´s index J = 1 from 6 dpo in the acute phase. IgM-ELISA gave slightly lower accuracy with J = 0.91 and 95.5% of both sensitivity and specificity; while SATR showed a markedly inferior yield (J = 0.41, sensitivity = 95.5%, specificity = 45.5%). The performances remained consistent in the convalescence phase of the disease (> 10 dpo).
CONCLUSIONS: Lepto-LF was found to be a reliable test for simple, rapid and early diagnosis of leptospirosis, resulting a promising tool for decentralizing leptospirosis diagnosis and enabling timely treatment of patients. In addition, Lepto-LF may be employed as confirmatory test, especially in remote areas and vulnerable contexts where the standard MAT is not available.
摘要：
目的：目前钩端螺旋体病诊断方法技术复杂，费用昂贵，对专业实验室的适用性有限。此外，他们在疾病的急性期缺乏诊断准确性，这与抗生素非常有效的时期相吻合。新的简单和准确的测试是强制性的，以分散和改善诊断。这里,我们为人类钩端螺旋体病引入了一种新的侧流免疫分析法（Lepto-LF）。
方法：我们使用104份血清样本进行了双盲分析，这些样本来自确诊或废弃的钩端螺旋体病诊断。Lepto-LF的诊断性能在症状发作（dpo）的不同天数范围内进行估计，将诊断算法作为参考标准。此外,将其与酶联免疫吸附试验（IgM-ELISA）和使用温度抗性抗原（SATR）的载玻片凝集试验进行了比较。
结果：Lepto-LF在急性期表现出完美的诊断性能，从6dpo开始，Youden指数J=1。IgM-ELISA的准确性略低，灵敏度和特异性均为J=0.91和95.5％；而SATR的产量明显较差（J=0.41，灵敏度=95.5％，特异性=45.5%)。在疾病的恢复期(>10dpo)表现保持一致。
结论：发现Lepto-LF是简单，快速和早期诊断钩端螺旋体病，为分散钩端螺旋体病诊断和及时治疗患者提供了有希望的工具。此外,Lepto-LF可以用作确认测试，特别是在标准MAT不可用的偏远地区和易受攻击的环境中。
方法：我们使用104份血清样本进行了双盲分析，这些样本来自确诊或废弃的钩端螺旋体病诊断。Lepto-LF的诊断性能在症状发作（dpo）的不同天数范围内进行估计，将诊断算法作为参考标准。此外,将其与酶联免疫吸附试验（IgM-ELISA）和使用温度抗性抗原（SATR）的载玻片凝集试验进行了比较。
结果：Lepto-LF在急性期表现出完美的诊断性能，从6dpo开始，Youden指数J=1。IgM-ELISA的准确性略低，灵敏度和特异性均为J=0.91和95.5％；而SATR的产量明显较差（J=0.41，灵敏度=95.5％，特异性=45.5%)。在疾病的恢复期(>10dpo)表现保持一致。
结论：发现Lepto-LF是简单，快速和早期诊断钩端螺旋体病，为分散钩端螺旋体病诊断和及时治疗患者提供了有希望的工具。此外,Lepto-LF可以用作确认测试，特别是在标准MAT不可用的偏远地区和易受攻击的环境中。
