Table 3.
Multiplex polymerase chain reaction (PCR) assay performance in a typhoid-endemic population in a clinical setting
| Suspected enteric fever cases (n = 680) | comparator (true positive) = blood culture | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| TP | FP | FN | TN | Se (%) | Spe (%) | LR+ | LR− | DOR | PT+ (%) | PT− (%) | |
| Multiplex PCR assay | 91 | 45 | 7 | 537 | 92.9 | 92.3 | 12.01 | 0.08 | 155.8 | 66 | 1 |
| Nga multiplex assay | 81‡ | 49 | 17* | 533† | 82.6 | 91.6 | 9.82 | 0.19 | 51.8 | 62 | 3 |
DOR = diagnostic odds ratio; FN = false negative; FP = false positive; Se = sensitivity; Spe = specificity; LR+ = positive likelihood ratio; LR− = negative likelihood ratio; PT+ = positive posttest probability; PT− = negative posttest probability; TN = true negative; TP = true positive. Performances in the clinical setting (CI = 95%) were calculated with R3.4.4 software and epiR package.
* Including one undetermined sample (both specific positive signal with S. Typhi and S. Paratyphi A).
† Including three undetermined samples.
‡ Including one discrepant result with BC.