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: 21 Aug 2019
Reviewer: Paolo Usai Satta
Reviewer's report:
This is a solid and complete systematic review about methods for diagnosing bile acid malabsorption. I
have not major methodological concerns, but some clarification is needed.
Why this manuscript is presented as a research article?
The mean sensitivity of SEHCAT was 87,3%, but there is a too large range in available studies with
respect to specificity. Similar problems are present about the other tests. The authors sould underline
these differences.
On the other hand the main problem of these tests is the absence of a gold standard.
How have sensitivity and specificity been calculate in absence of a gold standard?
Could it be used the "diagnostic yield" of each test (the prevalence of a positive test) as a better
alternative method?
The authors should better comment on these potential drawbacks (apart from the last lines of the
discussion) and add a sentence about the lack of a gold standard in the abstract. 
A minor point in the results of the abstract: "more than one tests was considered..." or "more than one
test...." (typing error?)
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.
Unable to assess
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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