Review for 10.1186/s12876-020-01322-y (2020)

Reviewer ’s report  
 
Title: Not so FAST. Commentary on the article “Appraisal of  the faecal haemoglobin, age and 
sex test (FAST) score in assessment of patients with lower bowel symptoms: an observational 
study ” 
 
Version: 0 Date: 18 Apr 2020  
 
Reviewer's report:  
 
Referring to the rationale for adopting FIT as triage test among patients wit h lower GI 
symptoms, the authors are commenting the results of the Scottish prospective observational 
study, aimed to evaluate the diagnostic performance of a risk score combining FIT results with 
age and sex. They have clearly outlined the challenges pose d by the adoption of triage strategies 
to decide about TC referral of patients presenting with clinical symptoms, showing the 
contribution of th e study to that specific field.  
 
I have just two comments:  
On page 5, lines 48 -51, the text might be more explic it, saying that that the results of the study 
validating the model (developed with the contribution of the authors) needed to be validated in 
prospective primary healthcare studies evaluating symptomatic patients. The study by Digby et 
al is reporting the results of such validation.  
 
Also, although, based on the NPV figure, the authors conclude that the FAST test is useful to 
identify subjects with a CRC risk similar to the risk of severe TC complications, they should also 
comment on the main conclusion of the study,  
" As a result of this study, we cannot support use of the published FAST score formula to assist 
in deciding who to refer for colonoscopy, since SBD was missed in those who had been referred 
using f -Hb and other considerations ….": which might suggest that the proposed score still 
shows important limitations  
 
Quality of written English  
Please indicate the quality of language in the manuscript:  
 
Acceptable  
 
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