Summary of findings'. ''Summary of findings' table 1.
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Review question: to assess the diagnostic accuracy of rapid diagnostic tests (RDTs) for detecting enteric fever in persons living in endemic areas presenting to a healthcare facility with fever Patients/population: clinically‐suspected enteric fever patients or unselected febrile patients Role: first test for enteric fever in patients presenting to a healthcare facility with fever in endemic areas Index tests: all RDTs specifically designed to enteric fever cases applied to patient blood or urine samples Reference standards: bone marrow culture, peripheral blood culture, peripheral blood culture, and polymerase chain reaction (PCR) on blood Studies: prospective cohort, retrospective case control Setting: healthcare facility in enteric fever endemic areas | ||||||
| Index test | Effect (95% confidence interval (CI)) |
Participants Total number, number with disease, (number of studies) |
Test result | Number of results per 1000 participants tested 1 (95% CI) | ||
| Prevalence 1% | Prevalence 10% | Prevalence 30% | ||||
| Typhidot (all types) |
Sensitivity 84 (73 to 91) Specificity 79 (70 to 87) |
6928, 982 (22) | TP FN FP TN |
8 (7 to 9) 2 (1 to 3) 208 (129 to 297) 782 (693 to 861) |
84 (73 to 91) 16 (9 to 27) 189 (117 to 270) 711 (630 to 783) |
252 (219 to 273) 48 (27 to 81) 147 (91 to 210) 553 (490 to 609) |
| Typhidot indeterminants reported or not applicable | Sensitivity 78 (65 to 87) Specificity 77 (66 to 86) |
5555, 662 (13) | TP FN FP TN |
8 (7 to 9) 2 (1 to 3) 228 (139 to 337) 762 (653 to 851) |
78 (65 to 87) 22 (13 to 35) 207 (126 to 306) 693 (594 to 774) |
234 (195 to 261) 66 (39 to 105) 161 (98 to 238) 539 (462 to 602) |
| Typhidot indeterminate results reported | Sensitivity 66 (59 to 73) Specificity 81 (58 to 93) |
1721, 339 (6) | TP FN FP TN |
7 (6 to 7) 3 (3 to 4) 188 (69 to 416) 802 (574 to 921) |
66 (59 to 73) 34 (27 to 41) 171 (63 to 378) 729 (522 to 837) |
198 (177 to 219) 102 (81 to 123 ) 133 (49 to 294) 567 (406 to 651) |
| TUBEX | Sensitivity 78 (71 to 85) Specificity 87 (82 to 91) |
4885, 627 (14) | TP FN FP TN |
8 (7 to 9) 2 (2 to 3) 129 (89 to 178) 861 (812 to 901) |
78 (71 to 85) 22 (15 to 29) 117 (81 to 162) 783 (738 to 819) |
234 (213 to 255) 66 (45 to 87) 91 (63 to 126) 609 (574 to 637) |
| Test‐it Typhoid and KIT prototypes (threshold > 1+) | Sensitivity 69 (59 to 78) Specificity 90 (78 to 93) |
2828, 682 (9) | TP FN FP TN |
7 (6 to 8) 3 (2 to 4) 99 (69 to 218) 891 (772 to 921) |
69 (59 to 78) 31 (22 to 41) 90 (63 to 198) 810 (702 to 837) |
207 (177 to 234) 93 (66 to 123) 70 (49 to 154) 630 (546 to 651) |
| Attributes of tests contributing to benefits and risks | ||||||
| Rapid diagnostic tests (RDTs)2 | RDTs are designed to provide test results typically in less than 1 hour, whereas currently used blood culture tests require 48 hours. The technical ability needed to conduct these rapid tests is designed to be lower than typical laboratory based tests, meaning they have the potential to be delivered nearer to the patient, further reducing time to diagnosis. However, some variants of the Typhidot test requires additional laboratory equipment, whereas the TUBEX and Test‐it Typhoid test do not. The TUBEX tests and some variants of Typhidot require cold chain storage. The Test‐it Typhoid test does not. In this Cochrane Review all included rapid tests were used on blood samples. None of the included studies conducted tests on urine samples. | |||||
| Overall certainty of evidence | ||||||
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Indeterminate results: for the Typhidot index test, there are concerns about studies which do not report indeterminate results (IgM negative and IgG positive). These results can frequently occur and if these results are not included in the analysis this biases study results to be overly‐optimistic. Case control studies: many of these studies use a case control design. This study design is at risk of overestimating both sensitivity and specificity. Reference standard: the highest grade of reference standard includes either bone marrow culture or PCR using blood, in addition to blood culture. However using bone marrow as a reference standard is invasive and more severe patients may be selected into these studies. Most included studies use only blood culture, and studies using more than 1 reference standard for example, PCR showed a reduction in RDT sensitivity by 20% to 25%. Precision: average estimates of both sensitivity and specificity have low precision, due to the heterogeneity between studies. Paired studies: there are few paired studies, where more than 1 test is used in the same patients. These studies provide the most direct evidence for comparing tests. Typhidot paired with TUBEX: Total 4245, 484 patients with disease. Typhidot paired with Test‐it Typhoid and KIT prototypes: no paired studies. Test‐it Typhoid and KIT prototypes paired with TUBEX: total 127, 64 patients with disease. It remains unclear if the tests were used in the same cohort of patients. | ||||||
Abbreviations: False Negatives (FN); False Positives (FP); immunoglobulin‐G (IgG); immunoglobulin‐M (IgM); Royal Tropical Institute, Amsterdam (KIT); polymerase chain reaction (PCR); True Negatives (TN); True Positives (TP).
1We used 2 systematic reviews of bacteraemia in Asia and Africa to inform prevalences of 30% (Asia); 10% (Africa: adults and children) and 1% (Africa: children) (Reddy 2010; Deen 2012). 2Keddy 2011.