Quality assessment (risk of bias)
All included studies will be assessed for risk of bias and their applicability based on the QUADAS 2 instrument12. The four key domains covering patient selection, index test, reference standard (comparator), and flow and timing will be evaluated. Any studies deemed to have a high risk of bias i.e. scoring ‘high’ for three or more of the four risk of bias domains, or concerns regarding applicability i.e. scoring ‘high’ for two or more of the three applicability domains will be excluded from further meta-analyses.