2.4. Risk of Bias Appraisal

The two reviewers independently appraised risk of bias based on the QUADAS-2 [37,38]. The QUADAS-2 consists of four key domains covering patient selection, index test, reference standard, and flow and timing. Each domain was assessed for risk of bias and applicability. Based on signalling questions (Table S1), each item could be answered with “high risk of bias”, “low risk of bias”, or “risk of bias unclear”. In case of disagreement between the two reviewers, a third reviewer was asked for judgement.