肥达试验及Tubex法在伤寒、甲型副伤寒诊断中的应用评估

目的 评估肥达试验、Tubex法在伤寒、甲型副伤寒诊断中的应用价值。方法 采集广西、新疆、云南等地区伤寒及甲型副伤寒暴发疫情中的确诊病例血清，运用肥达试验及Tubex-TF、Tubex-PA进行伤寒及甲型副伤寒血清抗体检测，分别计算这3 种血清学检测结果的灵敏度、特异度、假阳性率、假阴性率、约登指数和Kappa值等指标，对诊断结果进行评估。结果 以血培养为金标准，对23例血培养阳性的伤寒血清进行检测，Tubex-TF方法的灵敏度为82.61%，特异度为61.64%，阳性预测值为0.404，阴性预测值为0.918；Tubex-PA对伤寒病例的非特异性阳性检出率为91.30%。71例血培养阳性的甲型副伤寒检测结果显示，Tubex-PA方法的灵敏度为74.65%，特异度为16.00%，阳性预测值为0.716，阴性预测值为0.182；Tubex-TF对甲型副伤寒病例的非特异性检测阳性率为39.44%。Tubex-TF/PA联合对伤寒及甲型副伤寒病例的总检出率为80.21%。在不同病程中，血培养阳性的伤寒及甲型副伤寒病例血清进行肥达试验，阳性率均低于6.00%，明显低于Tubex法的检出率（2=75.165，P=0.000）。结论 疾病暴发流行时，除了肥达试验，Tubex-TF方法可用以辅助诊断伤寒，有利于该疾病早期发现、诊断及治疗，而对于甲型副伤寒的辅助诊断仍有待进一步研究。

Evaluation of Widal test and Tubex for diagnosis of typhoid and paratyphoid A

Objective To evaluate the efficiency of Widal test and Tubex detection on diagnosis of typhoid and paratyphoid A. Methods Serum samples collected from the blood culture confirmed cases of typhoid and paratyphoid A in Guangxi, Xinjiang and Yunnan provinces during the outbreaks were used for Widal test and Tubex (Tubex-TF and Tubex-PA) detection of the specific antibodies against Salmonella Typhi and Salmonella Paratyphi A. The diagnostic accuracy of the three methods was evaluated with the culture method as the gold standard. Results The results showed that for 23 culture-confirmed typhoid cases, the sensitivity and specificity of Tubex-TF were 82.61% and 61.64%, respectively, with the positive predictive value of 40.40% (PPV) and negative predictive value (NPV) of 91.80%, and Tubex-PA showed 91.30% positive detection rate. While for 71 culture-confirmed paratyphoid A cases, the sensitivity and specificity of Tubex-PA were 74.65% and 16.00%, respectively, with PPV of 71.60% and NPV of 18.20%. The positive detection of Tubex-TF was 39.44%. The combined positive detection rate of Tubex-TF and Tubex-PA for typhoid and paratyphoid A was 80.21%. Compared with the high detection rate of Tubex, Widal test showed lower detection rate (6.00%) for typhoid and paratyphoid A(2=75.165, P=0.000). Conclusions During the outbreak or epidemic, besides Widal test, Tubex-TF can be used in early detection of typhoid, while the its effect in early serological diagnosis of paratyphoid A needs further research.