Table 3 Modified elements of the QUADAS2 signalling questions used for quality assessment
Domain | Patient selection | Index test* | Reference standard | Flow and timing |
|---|---|---|---|---|
Description | Describe methods of patient selection: Describe included patients (prior testing, presentation, intended use of index test and setting): | Describe the index test and how it was conducted and interpreted: | Describe the reference standard and how it was conducted and interpreted: | Describe any patients who did not receive the index test(s) and/or reference standard or who were excluded from the 2x2 table (refer to flow diagram): Describe the time interval and any interventions between index test(s) and reference standard: |
Signalling questions (yes/no/unclear) | Was a consecutive or random sample of patients enrolled? | Were the index test results interpreted without knowledge of the results of the reference standard? | Is the reference standard likely to correctly classify the target condition? | Was there an appropriate interval between index test(s) and reference standard? |
Was a case-control design avoided? | Were index test acquisition and analysis parameters determined a priori and consistent for all study participants? | Were the reference standard results interpreted without knowledge of the results of the index test? | Did all patients receive a reference standard? | |
Did the study avoid inappropriate exclusions? i.e. Participants may be excluded if justified in terms of interference with index test measurement (corneal opacities preventing visualisation of anterior structures). | Did all patients receive the same reference standard? i.e. Was the reference test conducted in the same way for each patient? For slit lamp examination: observer, slit lamp settings For laboratory protein measurements: method of aqueous extraction, sample storage and analysis. | |||
Were all patients included in the analysis? | ||||
Risk of bias: High/low/unclear | Could the selection of patients have introduced bias? | Could the conduct or interpretation of the index test have introduced bias? | Could the reference standard, its conduct, or its interpretation have introduced bias? | Could the patient flow have introduced bias? |
Concerns regarding applicability: High/low/unclear | Are there concerns that the included patients do not match the review question? | Are there concerns that the index test, its conduct, or interpretation differ from the review question? | Are there concerns that the target condition as defined by the reference standard does not match the review question? |