Table 5 Summary of Widal performances in earlier studies
Authors | Date | Study Country | Sample Size | Age classes included | Prevalence of S. typhi in participants | Sensitivity | Specificity | PPV | NPV | Cut Off Titer | Control Group(s) | Gold Standard |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Choo et al. | 1993 | Malaysia | 2382 | Children | 6.1% | 89% | 89% | < 50% | 99.2% | O or H ≥1:40 | Non-typhoid febrile children admitted to hospital | Blood Culture |
Parry et al. | 1999 | Vietnam | 2000 | Children & Adults | 30.8% | O: 49% H: 67%; O or H ≥1:100:88% | O: 97% H: 96%; O or H ≥1:100:87% | O: 88% H: 88%; O or H ≥1:100:74% | O: 82% H: 87%; O or H ≥1:100:94% | O:≥1:200 H: ≥1:100; O or H ≥1:100 | Lab confirmed malaria, dengue or bacteremia | Blood Culture |
Wilke et al. | 2002 | Turkey | 410 | ≥18 y | 13.2% | 52% Post 7-10 d: 90% | 88% Post 7-10 d: 90% | 76% Post 7-10 d: 88% | 71% Post 7-10 d: 93% | O: ≥1:200 H: ≥1:200 | Healthy controls, nontyphoidal febrile patients, blood culture negative febrile cases | Blood Culture, Stool Culture |
Olsen et al. | 2004 | Vietnam | 80 | ≥3y | 73.8% | 64% (field) 61% (lab) | 76% (field) 100% (lab) | 88% (field) 100% (lab) | 43% (field) 48% (lab) | O or H ≥1:100 | Lab confirmed bacteremia, AFB, dengue, malaria, pos. stool culture, pos. urine culture | Blood Culture |
Ley et al. | This study | Tanzania | 1680 | 2 m. - 14y | 1% | 75% | 98% | 26% | 100% | H: ≥1:80 | Non-typhoid febrile children admitted to hospital | Blood Culture |