Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmácia, Odontologia e Enfermagem, Universidade Federal do Ceará, Fortaleza, CE, Brasil.
Rev Soc Bras Med Trop. 2012 Jul-Aug;45(4):510-3. doi: 10.1590/s0037-86822012000400019.
The laboratory diagnosis of schistosomiasis is based mainly on the detection of parasite eggs in stool samples through the Kato-Katz (KK) technique, reading one slide by test. However, a widely known limitation of parasitological methods is reduced sensitivity, particularly in low endemic areas.
To increase sensitivity, we conducted further slide readings from the same stool sample using the parasitological method associated with a serological test. We used the KK method (three slides) and the IgG anti-Schistosoma mansoni-enzyme-linked immunosorbent assay (ELISA) technique to diagnose schistosomiasis in low endemic areas in the Brazilian State of Ceará. Fecal samples and sera from 250 individuals were analyzed.
Sixteen percent and 47.2% of samples were positive in parasitological tests and serological tests, respectively. Parasitological methods showed that 32 (80%) individuals tested positive on the first slide, 6 (15%) on the second slide, and 2 (5%) on the third. The performance of the ELISA test in the diagnosis, using the KK method as diagnostic reference, showed a negative predictive value of 100%, with specificity and positive predictive values of 62.8% and 33.9%, respectively.
In this study, the increase from one to three slides analyzed per sample using the KK technique was shown to be a useful procedure for increasing the diagnostic sensitivity of this technique.
血吸虫病的实验室诊断主要基于通过加藤氏(Kato-Katz, KK)技术检测粪便样本中的寄生虫卵，每个样本检测一张载玻片。然而，寄生虫学方法的一个众所周知的局限性是敏感性降低，尤其是在低流行地区。
为了提高敏感性，我们使用与血清学检测相关的寄生虫学方法对同一粪便样本进行进一步的载玻片阅读。我们在巴西塞阿拉州的低流行地区使用 KK 法（三张载玻片）和 IgG 抗曼氏血吸虫酶联免疫吸附试验（ELISA）技术来诊断血吸虫病。分析了 250 名个体的粪便样本和血清。
寄生虫学检测和血清学检测的阳性率分别为 16%和 47.2%。寄生虫学方法显示，32 名（80%）个体在第一张载玻片上呈阳性，6 名（15%）在第二张载玻片上呈阳性，2 名（5%）在第三张载玻片上呈阳性。在使用 KK 法作为诊断参考的情况下，ELISA 检测在诊断中的表现为阴性预测值为 100%，特异性和阳性预测值分别为 62.8%和 33.9%。
在这项研究中，使用 KK 技术对每个样本进行从一张到三张载玻片的分析增加被证明是提高该技术诊断敏感性的有用程序。
