Review for 10.1186/1471-230X-13-35 (2013)

Reviewer's report
Title:A re-evaluation of the scratch test for locating the liver edge: a reliable
physical sign
Version: 1Date:14 December 2012
Reviewer: Jochen Schuld
Reviewer's report:
A re-evaluation of the scratch test for locating the liver edge: a reliable physical
sign
To the authors:
The authors present a study comparing the clinical examination of the liver edge
with standard ultrasound.
1. I have no concern with the methods clinically and statistically used in the
paper. The abbreviation “ICC” has to be explained before first appearance in the
text (see “Results” in the abstract)
2. The term “body habitus” sounds imprecisely and should be corrected. The
cut-off p-value considered as statistically significant and the tests used to
compare patients (see also comments concerning results section) should be
provided.
3. Were the patients continuously breathing during the examinations or stopped
they breathing during measurements?
4. The authors should clearly determinate “underestimation” and furthermore
“overestimation” in relation to the reference point (below/above/nearer to the
pelvis or the clavicle).
5. The authors should provide the main biometric statistics concerning the
patients included in both parts of the study (e.g. age, male/female, height, weight
and the resulting body mass index).
6. Furthermore, authors have to describe the differences between the 15 patients
examined by Rater 1 and the 16 patients examinded by Rater 2 using standard
statistical tests.
7. The y-axis on table 2 is missing (“Rater 1”, isn’t it?)
8. Authors postulate that a Spearmans rho of 0.37 shows only a moderate
agreement. That is generally right. I would suppose to underline that statement
with the corresponding literature.
9. The y-axis of figure 3 (“….raters pooled”) doesn’t correspond to that what is
written in the text (“….difference between a rater”). Please correct or comment on
that.
10. The calculation of ratings within the 1,2 or 3 cm of the reference value has to
be described in the methods section. How did you define 1 cm, 2 cm and 3 cm.
Perhaps 0.5 cm/2cm and 1.5 cm above and below the reference value? Please
comment on that, as written in the paper, it sounds somehow misleading.
11. Figure 4 should be omitted. Instead of that figure, a second Bland Altman
Graph should be provided comparing twq BMI-groups at a cut-off value (set at
the median BMI).
12. Linear regression analysis should be provided as a table with RR
(alternatively : exp (beta)), 95% confidence interval and p-value.
Discussion:
1. The authors should discuss more extensively their paper concerning clinical
relevance of knowing the lower liver edge in the midclavicular line.
2. The fact that physicians tend to underestimate objects and intraoperative
findings is well known. The authors should cite some recent papers and discuss
their results in that context.
3. After having read the article, the reader gets the impression (especially based
on the statistical tests) that the scratch test is reliable but not precise. The
authors should include this fact into the title of their paper. “Re-evaluation….:
reliable but imprecise.”).
4. The authors should discuss the limitations of their study; small number of
patients included in the study and the natural bias which may be given by the
rater itself (degree of hearing loss etc.)
5. The authors should discuss their results in the context of further medical
education for students
1. Is the question posed by the authors well defined? yes
2. Are the methods appropriate and well described? See comments
3. Are the data sound? yes
4. Does the manuscript adhere to the relevant standards for reporting and data
deposition? Yes, but see comments
5. Are the discussion and conclusions well balanced and adequately supported
by the data?
6. Are limitations of the work clearly stated? no
7. Do the authors clearly acknowledge any work upon which they are building,
both published and unpublished? n.a.
8. Do the title and abstract accurately convey what has been found? No, see
comments
9. Is the writing acceptable? Yes
I therefore recommend “Major revisions”
Level of interest: An article whose findings are important to those with closely
related research interests
Quality of written English: Acceptable
Statistical review: No, the manuscript does not need to be seen by a
statistician.
Declaration of competing interests:
'I declare that I have no competing interests'