Laboratório de Pesquisas Clínicas, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz (FIOCRUZ), Belo Horizonte, Minas Gerais, Brazil Departamento de Epidemiologia, Instituto de Medicina Social, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil.
Trop Med Int Health. 2012 Oct;17(10):1202-7. doi: 10.1111/j.1365-3156.2012.03064.x. Epub 2012 Aug 16.
To estimate the sensitivities and specificities of different diagnostic tests for visceral leishmaniasis (VL) using latent class analysis (LCA).
This study was performed using data from a prospective study conducted in four Brazilian states from May 2004 to May 2007. Five diagnostic tests for VL were evaluated in 285 VL cases and 119 non-cases: microscopy, indirect fluorescence antibody test (IFAT), enzyme-linked immunosorbent assay using recombinant K39 antigen (rK39-ELISA), direct agglutination test (DAT) and the rK39 rapid test.
Microscopy showed sensitivity of 77.0% (CI: 71.5-81.5) and specificity of 99.0% (CI: 94.0-99.7). The IFAT and the DAT showed similar sensitivities, 88.3% (CI: 84.0-92.0) and 88.5% (CI: 84.1-92.0), respectively, but the DAT had a higher specificity (95.4%, CI: 89.2-98.1) than did the IFAT (83.0%, CI: 75.0-88.2). The rK39-ELISA and the rK39 rapid test showed sensitivities of 99.0% (CI: 96.3-99.6) and 94.0% (CI: 90.1-96.3), and specificities of 82.5% (CI: 75.0-88.3) and 100% (CI: 97.0-100.0%), respectively.
Considering the lack of an adequate reference standard, LCA proved to be a useful tool in validating diagnostic methods for VL. The DAT and the rK39 rapid test showed better performance. Thus, clinically suspected cases of VL in a Brazilian endemic area could be treated based on the positivity of one of these tests.
使用潜在类别分析（LCA）估计不同诊断检测方法用于内脏利什曼病（VL）的敏感性和特异性。
本研究使用 2004 年 5 月至 2007 年 5 月在巴西四个州进行的前瞻性研究的数据进行。在 285 例 VL 病例和 119 例非病例中评估了 5 种 VL 诊断检测方法：显微镜检查、间接荧光抗体试验（IFAT）、使用重组 K39 抗原的酶联免疫吸附试验（rK39-ELISA）、直接凝集试验（DAT）和 rK39 快速检测。
显微镜检查的敏感性为 77.0%（95%CI：71.5-81.5），特异性为 99.0%（95%CI：94.0-99.7）。IFAT 和 DAT 的敏感性相似，分别为 88.3%（95%CI：84.0-92.0）和 88.5%（95%CI：84.1-92.0），但 DAT 的特异性更高（95.4%，95%CI：89.2-98.1）高于 IFAT（83.0%，95%CI：75.0-88.2）。rK39-ELISA 和 rK39 快速检测的敏感性分别为 99.0%（95%CI：96.3-99.6）和 94.0%（95%CI：90.1-96.3），特异性分别为 82.5%（95%CI：75.0-88.3）和 100%（95%CI：97.0-100.0%）。
考虑到缺乏适当的参考标准，LCA 被证明是验证 VL 诊断方法的有用工具。DAT 和 rK39 快速检测表现更好。因此，在巴西流行地区，疑似临床 VL 病例可根据这些检测方法中的一种的阳性结果进行治疗。
