The review addressed a clear objective supported by inclusion criteria defined in terms of population and index test. Details were lacking on reference standard and outcome data were poorly specified. The literature search was limited to electronic databases without additional attempts to locate studies, such as screening bibliographies or contacting experts in the field. In addition, the review was restricted to published English language studies. This meant that it was possible that relevant studies could have been missed and the review may be subject to language and publication bias. Details on the review process were not reported, so it was not possible to determine whether appropriate steps were taken to minimise reviewer bias and errors.
Study quality was not assessed, so the reliability of the included studies was unclear. Few details were provided on the included studies, which made it difficult to determine the generalisability of the review findings. Although heterogeneity was assessed, explanations for the observed heterogeneity were not investigated, so pooled values should be interpreted with caution.
The authors' conclusions are supported by the data presented, but should be interpreted with extreme caution given possibility of missing studies, failure to assess study quality and heterogeneity between studies.