International Vaccine Institute, Seoul, Korea.
BMC Infect Dis. 2010 Jun 22;10:180. doi: 10.1186/1471-2334-10-180.
The diagnosis of typhoid fever is confirmed by culture of Salmonella enterica serotype Typhi (S. typhi). However, a more rapid, simpler, and cheaper diagnostic method would be very useful especially in developing countries. The Widal test is widely used in Africa but little information exists about its reliability.
We assessed the performance of the Widal tube agglutination test among febrile hospitalized Tanzanian children. We calculated the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of various anti-TH and -TO titers using culture-confirmed typhoid fever cases as the "true positives" and all other febrile children with blood culture negative for S. typhi as the "true negatives."
We found that 16 (1%) of 1,680 children had culture-proven typhoid fever. A single anti-TH titer of 1:80 and higher was the optimal indicator of typhoid fever. This had a sensitivity of 75%, specificity of 98%, NPV of 100%, but PPV was only 26%. We compared our main findings with those from previous studies.
Among febrile hospitalized Tanzanian children with a low prevalence of typhoid fever, a Widal titer of > or = 1:80 performed well in terms of sensitivity, specificity, and NPV. However a test with improved PPV that is similarly easy to apply and cost-efficient is desirable.
伤寒的诊断通过培养沙门氏菌血清型 Typhi（S. typhi）来确认。然而，一种更快速、更简单、更便宜的诊断方法将非常有用，尤其是在发展中国家。肥达氏试验在非洲广泛应用，但关于其可靠性的信息很少。
我们评估了发热住院坦桑尼亚儿童中肥达氏试管凝集试验的性能。我们使用培养确认的伤寒病例作为“真阳性”，将所有其他血培养阴性的发热儿童作为“真阴性”，计算了各种抗 TH 和抗 TO 滴度的敏感性、特异性、阳性预测值（PPV）和阴性预测值（NPV）。
我们发现 16 名（1%）1680 名儿童患有培养证实的伤寒。单份抗 TH 滴度为 1:80 及以上是伤寒的最佳指标。其敏感性为 75%，特异性为 98%，NPV 为 100%，但 PPV 仅为 26%。我们将主要发现与以前的研究进行了比较。
在伤寒患病率较低的发热住院坦桑尼亚儿童中，>或=1:80 的肥达氏试验在敏感性、特异性和 NPV 方面表现良好。然而，需要一种具有改进的 PPV、同样易于应用且具有成本效益的测试。
