Table 2 Risk of bias assessment performed with the Quality of Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool

Risk of bias

Applicability concerns

Domain 1: Patient selection

Domain 2: Index text

Domain 3: Reference standard

Domain 4: Flow and timing

Patient selection

Index test

Reference standard

1. Was a consecutive or random sample of patients enrolled?

2. Was a a case-control design avoided?

3. Did the study avoid inappropriate exclusions?

1. Were the index test results interpreted without knowledge of the reference standard?

2. If a threshold was used, was it pre-specified?

1. Is the reference standard likely to correctly classify the target condition?

2. Were the reference standard results interpreted without knowledge of the results of the index?

1. Was there an appropriate interval between index test and reference standard?

2. Did all patients receive the same reference standard?

3. Were all patients included in the analysis?