Review for 10.1186/s12876-019-1102-1 (2019)

Reviewer’s report
Title: Methods for Diagnosing Bile Acid Malabsorption: A Systematic Review
Version: 0 Date: 01 Oct 2019
Reviewer: Renato Bocchini
Reviewer's report:
It is a complete and exhaustive review about bile acid malabsorption diagnosis; I have some question:
1.Why  patients  with  previous  surgery  have  been  excluded?  considering  that  "  review  was
intended to evaluate and compare the available evidence on the diagnostic accuracy (i.e. sensitivity and
specificity) of different methods" I think that they could have been included; actually surgical patients
malabsorption of bile acids is quoted at the beginning of discussion and conclusion 
2.for the same reason ("diagnostic accuracy of different methods") it appears a bit difficult to
compare different papers utilizing different methods ; wouldn't have been better to utilize just the few
papers comparing available methods? that considering that an actual gold standard is missing; and this
is a problem concerning even other reviews (Valentin 2016) and papers (Fani,2018)
3.finally,  about  diagnotic  accuracy  of  SeHCAT:  the  sentence  "  Thus,  Se  retention  can  be
considered an index of BAM causing chronic diarrhea" could be modified defining retention diagnostic
value: for example "retention &lt;10% can be...."
Are the methods appropriate and well described?
If not, please specify what is required in your comments to the authors.
Yes
Does the work include the necessary controls?
If not, please specify which controls are required in your comments to the authors.
Yes
Are the conclusions drawn adequately supported by the data shown?
If not, please explain in your comments to the authors.
Yes
Are you able to assess any statistics in the manuscript or would you recommend an additional
statistical review?
If  an  additional  statistical  review  is  recommended,  please  specify  what  aspects  require  further
assessment in your comments to the editors.
Not relevant to this manuscript
Quality of written English
Please indicate the quality of language in the manuscript:
Acceptable
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