Table 2 Quality assessment of the DOK study design (QUADAS-2)
From: Challenges in diagnostic accuracy studies in primary care: the fecal calprotectin example
| Signaling questions | Answer | Risk of bias/applicability | Planned adjustment |
|---|---|---|---|
| Domain 1: Patient selection | |||
| Risk of bias | Low risk | ||
| Is a consecutive sample of patients enrolled? | Yes | ||
| Is a case-control design avoided? | Yes | ||
| Does the study avoid inappropriate exclusions? | Yes | ||
| Applicability | High concern | - Magnitude will be evaluated | |
| Are there concerns that the included patients and setting do not match the topic of our study (patients had symptoms suggestive of inflammatory bowel disease in primary care)? | |||
| Domain 2: Index test | |||
| Risk of bias | Low Risk | ||
| Are the index test results interpreted without knowledge of the results of the reference standard? | Yes | ||
| If a threshold was used, is it pre-specified? | Yes | ||
| Applicability | Low Concern | ||
| Are there concerns that the index test, its conduct, or interpretation differ from the topic of our study (fecal calprotectin was measured with ELISA)? | |||
| Domain 3: Reference standard | |||
| Risk of bias | High risk | ||
| Is the reference standard likely to correctly classify the target condition? | No | - Probably not clinically relevant | |
| - Adjustment in analysis [30, 31] | |||
| Are the reference standard results interpreted without knowledge of the results of the index test? | Yes | ||
| Domain 4: Flow and timing | |||
| Risk of bias | High risk | ||
| Is there an appropriate interval between index test and reference standard? | No | - Represents care as usual | |
| - Repeated measurement index test before endoscopy | |||
| Do all patients receive a reference standard? | Yes | ||
| Do all patients receive the same reference standard? | No | - Adjustment in analysis [30, 31] |