The validity of the studies selected for inclusion was assessed according to the following 11 criteria.
1. Did the authors provide a clear description of the SVCT technique employed?
2. Were there clear criteria for a positive or negative result?
3. Was the reliability of the result assessed by comparing independent (blinded) readings?
4. Was the reliability of the result assessed by repeat testing?
5. Was the patient selection process described in sufficient detail?
6. Were there sufficient details about the patient population studied?
7. Were there sufficient details about eligible patients who were not included in the study?
8. Was the extent of disease described in sufficient detail to allow stratification of the results by location or severity of disease?
9. Were non-PE diagnoses reported?
10. Were patients tested by SVCT or the reference, regardless of a previous test with either?
11. Were the results of SVCT and reference standard studies interpreted independently?
The authors did not state how the papers were assessed for validity, or how many reviewers performed the validity assessment.