Critical appraisal:Terhaar sive Droste JS, Oort FA, van der Hulst RW, van Heukelem HA, Loffeld RJ, van Turenhout ST, et al 2011 2

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Risk of bias assessment: diagnostic accuracy study

Patient Selection
Prior tests and any referral filters
Condition that defined entry into study
all ambulatory subjects over the age of 40 years scheduled

to undergo elective colonoscopy from June 2006 to
January 2009 at 1 of the 5 participating hospitals were
invited to participate in this study. Invitation was either
in person by the referring gastroenterologist or through
telephone by 1 of 5 research workers stationed at each of
the participating centers.

inflammatory bowel disease (IBD), subjects who failed
to complete the test and subjects in whom no written
informed consent was obtained were excluded from
further analysis. excluded subjects with incomplete
colonoscopies and subjects with inadequate bowel
cleansing, as judged by the endoscopist.

Setting
Two of these 5 participating hospitals are situated

in rural areas, another two are large teaching hospitals
with an urban population. One of the centers is an
academic medical center with a predominantly urban
population.

Was a diagnostic case-control design avoided?
Yes
Consecutive or random sample?
Yes
Did the study avoid inappropriate exclusions?
Yes
Reasons
If comparing more than one index test was the design fully paired or paired randomly?
Not applicable
If a paired randomised design was used, was allocation to groups concealed and was the generation of allocation sequence adequate?
Not applicable
What is the risk that the selection of participants introduced bias?
Low
Comments
Index test 1
Describe index test and how it was conducted and interpreted
automated

quantitative OC-sensor test (Eiken Chemical Co.). The
FIT was sampled from stool produced the day before
colonoscopy and bowel preparation had started. Subjects
were excludedwhen the FITwas sampled after initiation of
bowel preparation.

Illustrated instructions guided the participants
to sample their stool ensuring that contact with
water and urine was prevented. Norestrictions weremade
with regard to diet during the week in which the stool
sample was taken (14).

All FITs were stored at
�5�C on arrival. Tests were analyzed using the OC sensor
MICRO desktop analyzer (Eiken Chemical Co.) according
to themanufacturer’s instructions (15).Testswereanalyzed
within 1 week by 1 of the 2 experienced technicians who
wereunaware of the clinicaldata

Were the index test results interpreted without knowledge of the results of the reference standard?
Yes
If a threshold was used, was it pre-specified?
Yes
If two tests are being compared, have they been assessed independently / blind to each other?
Not applicable
What is the risk that the conduct or interpretation of the index test introduced bias?
Low
Comments
Index test 2
Describe index test and how it was conducted and interpreted, if applicable
Were the index test results interpreted without knowledge of the results of the reference standard?
Not applicable
If a threshold was used, was it pre-specified?
Not applicable
What is the risk that the conduct or interpretation of the index test introduced bias?
Not applicable
Comments
Reference Standard
Describe the reference standard and how it was conducted and interpreted
performed or supervised by experienced

gastroenterologists. Endoscopists were blinded to the FIT
result. The results of histopathologic
analysis of tissue samples obtained during colonoscopy
were the standard of reference for the diagnosis of adenoma
or cancer. Surgical

Is the reference standard likely to correctly classify the target condition?
Yes
Were the reference standard results interpreted without knowedge of the results of the index test/s?
Yes
Was the reference test standard independent of the index test?
(i.e. the index test did not form part of the reference standard)
Yes
What is the risk that the reference standard, its conduct or interpretation introduced bias?
Low
Comments
Flow and timing
Describe any patients who did not receive the index test(s) and/or reference standard or who were excluded from the 2x2 table
Describe the time interval and any interventions between index test(s) and reference standard
sampled one day prior to colonoscopy
If a predictive test (the reference standard is a later event that the test aims to predict) were any subsequent interventions between test and later event blind to test result?
Not applicable
Was there an appropriate interval between index test(s) and reference standard?
Yes
Did either all participants or a random sample of participants receive a reference standard test?
Yes
Did all patients receive the same reference standard irrespective of index test result?
Yes
Were all test results including unclear results reported?
Yes
Were all patients included in the analysis?
Yes
What is the risk that the patient flow introduced bias?
Low
Comments
Overall risk of bias
Low risk of bias Additional comments:


Jutta's tick icon.png This appraisal has been completed.


Article
Terhaar sive Droste JS, Oort FA, van der Hulst RW, van Heukelem HA, Loffeld RJ, van Turenhout ST, et al. Higher fecal immunochemical test cutoff levels: lower positivity rates but still acceptable detection rates for early-stage colorectal cancers. Cancer Epidemiol Biomarkers Prev 2011 Feb;20(2):272-80 Available from: http://www.ncbi.nlm.nih.gov/pubmed/21135261.
Assigned to
User:Melissa.chow
Topic area
Guidelines:Colorectal cancer
Clinical question
Form
Form:Quality appraisal quadas


Section below only relevant for Cancer Council Project Officer

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