Quality appraisal of the included studies using the QUADAS-2 tool
| Study | Bias (internal validity) | Applicability concerns (external validity) | |||||
|---|---|---|---|---|---|---|---|
| Selection of patients | Index test | Reference standard | Flow and timing | Selection of patients | Index test | Reference standard | |
| Abraham et al. (46) | Low risk | Unclear | Unclear | Low risk | Low risk | Unclear | Low risk |
| Alonso Alvarez et al. (76) | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
| Amir et al. (56) | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
| Andreu et al. (77) | Low risk | Low risk | Low risk | Low risk | Low risk | Unclear | Low risk |
| Askenov et al. (78) | Low risk | Unclear | Low risk | Unclear | Low risk | Low risk | Low risk |
| Ayappa et al. (47) | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
| Bajwa et al. (57) | High risk | High risk | Unclear | Low risk | Unclear | High risk | Low risk |
| Berry et al. (79) | Low risk | Low risk | Low risk | High risk | Low risk | Low risk | Low risk |
| Bridevaux et al. (80) | High risk | Low risk | Low risk | Unclear | Unclear | Low risk | Low risk |
| Campbell et al. (81) | Low risk | Unclear | Low risk | Low risk | Low risk | Low risk | Low risk |
| Candela et al. (58) | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
| Cheliout et al. (59) | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
| Chung et al. (82) | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
| Churchward et al. (83) | Unclear | High risk | Unclear | Unclear | Unclear | Unclear | Low risk |
| Cilli et al. (84) | High risk | High risk | Unclear | Unclear | Unclear | Unclear | Low risk |
| Danzi-Soares et al. (85) | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
| Divo et al. (60) | High risk | Low risk | Low risk | Low risk | Unclear | Low risk | Low risk |
| Driver et al. (61) | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
| Ferre et al. (62) | High risk | High risk | Unclear | Low risk | Unclear | High risk | Low risk |
| Finkel et al. (86) | Low risk | Unclear | Unclear | High risk | Low risk | Low risk | Low risk |
| Fordyce et al. (87) | Low risk | Unclear | Unclear | Unclear | Low risk | Low risk | Low risk |
| Furokawa et al. (88) | High risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
| Garcia-Diaz et al. (48) | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
| Gjevre et al. (89) | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
| Goodrich et al. (63) | Low risk | Low risk | Low risk | Low risk | Unclear | Low risk | Low risk |
| Grant et al. (64) | High risk | Unclear | Low risk | Unclear | Unclear | Low risk | Low risk |
| Grover et al. (90) | High risk | Low risk | Low risk | Low risk | Unclear | Low risk | Unclear |
| Hernandez et al. (91) | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
| Kuna et al. (49) | High risk | Low risk | Unclear | Low risk | Unclear | Low risk | Unclear |
| Kuna et al. (92) | High risk | Low risk | Unclear | Unclear | Unclear | Low risk | Unclear |
| Kushida et al. (50) | High risk | Low risk | Low risk | Unclear | Unclear | Low risk | Unclear |
| Lettieri et al. (93) | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
| Levendowski et al. (94) | Low risk | Low risk | Unclear | Unclear | Low risk | Low risk | Unclear |
| Masa JF et al. (95) | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
| Masdue et al. (96) | Low risk | Low risk | Low risk | Unclear | Low risk | Low risk | Unclear |
| Nakayama et al. (97) | High risk | Low risk | Unclear | Low risk | Unclear | Low risk | Unclear |
| Ng et al. (65) | High risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
| Ng et al. (66) | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
| Nigro et al. (67) | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
| Onder et al. (68) | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Unclear |
| Orr et al. (69) | High risk | Unclear | Unclear | Unclear | High risk | Unclear | Unclear |
| Polese et al. (51) | Low risk | Low risk | Low risk | Unclear | Low risk | Low risk | Low risk |
| Quintana-Gallego et al. (98) | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
| Rosen et al. (99) | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
| Santos-silva et al. (52) | Low risk | Low risk | Low risk | Low risk | Low risk | High risk | Low risk |
| Shrivastava et al. (100) | Unclear | Unclear | Unclear | Unclear | Unclear | Low risk | Unclear |
| Skomro et al. (102) | Low risk | Low risk | Unclear | Low risk | Low risk | High risk | Unclear |
| Skomro et al. (101) | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
| Smith et al. (53) | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Unclear |
| Su et al. (70) | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
| Sullivan et al. (71) | High risk | Unclear | Unclear | Unclear | Unclear | Low risk | Unclear |
| Takama et al. (72) | Low risk | Unclear | Unclear | Low risk | Low risk | Low risk | Unclear |
| Tiihonen et al. (54) | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
| Tiihonen et al. (73) | High risk | Low risk | Low risk | Low risk | Unclear | Low risk | Low risk |
| To et al. (74) | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
| To et al. (103) | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
| Tonelli de Oliveira et al. (55) | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
| Yagi et al. (75) | High risk | Low risk | Low risk | Low risk | Unclear | Low risk | Low risk |
| Yin et al. (104) | Unclear | Low risk | Low risk | Unclear | Unclear | Low risk | Low risk |
Note: QUADAS-2 = Quality Assessment of Diagnostic Accuracy Studies-2.