Table 2 QUADAS-2 questions. Results of the analysis for the quality evaluation are shown in Fig. 3

A. patient selection

Was a consecutive or random sample of patient enrolled?

Was a case control design avoided?

Did the study avoid in appropriate exclusion?

B. index test

were the index test interpreted without knowledge of results of the reference standard?

if a threshold was used, was pre- specified?

C. Reference standard

Is the reference standard likely results interpreted without knowledge of the result of the index tests?

D. flow and timing

Was there an appropriate interval between index tests and reference standard?

Did all the patients receive the same reference standard?

Were all patients included in the analysis?