CASP Checklist:
12 questions to help you make sense of a Diagnostic Test study
How to use this appraisal tool: Three broad issues need to be considered when appraising a
trial:
Are the results of the study valid? (Section A)
What are the results? (Section B)
Will the results help locally? (Section C)
The 12 questions on the following pages are designed to help you think about these issues
systematically. The first three questions are screening questions and can be answered
quickly. If the answer to both is “yes”, it is worth proceeding with the remaining questions.
There is some degree of overlap between the questions, you are asked to record a “yes”,
“no” or “can’t tell” to most of the questions. A number of italicised prompts are given after
each question. These are designed to remind you why the question is important. Record your
reasons for your answers in the spaces provided.
About: These checklists were designed to be used as educational pedagogic tools, as part of a
workshop setting, therefore we do not suggest a scoring system. The core CASP checklists
(randomised controlled trial & systematic review) were based on JAMA 'Users’ guides to the
medical literature 1994 (adapted from Guyatt GH, Sackett DL, and Cook DJ), and piloted with
health care practitioners.
For each new checklist, a group of experts were assembled to develop and pilot the checklist
and the workshop format with which it would be used. Over the years overall adjustments
have been made to the format, but a recent survey of checklist users reiterated that the basic
format continues to be useful and appropriate.
Referencing: we recommend using the Harvard style citation, i.e.: Critical Appraisal Skills
Programme (2018). CASP (insert name of checklist i.e. Diagnostic Test Study) Checklist.
[online] Available at: URL. Accessed: Date Accessed.
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Section A: Are the results of the trial valid?
1. Was there a clear question
for the study to address?
Yes
HINT: A question should include
information about
the population
the test
the setting
the outcomes
Can’t Tell
No
Comments:
2. Was there a comparison
with an appropriate
reference standard?
Yes
HINT: Is this reference test(s) the best
available indicator in the circumstances
Can’t Tell
No
Comments:
Is it worth continuing?
3. Did all patients get the
diagnostic test and
reference standard?
Yes
HINT: Consider
were both received regardless of the
results of the test of interest
Check the 2x2 table (verification
bias)
Can’t Tell
No
Comments:
Paper for appraisal and reference:
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4. Could the results of the test
have been influenced by the
results of the reference
standard?
Yes
HINT: Consider
was there blinding
were the tests performed
independently
review bias
Can’t Tell
No
Comments:
5. Is the disease status of the
tested population clearly
described?
Yes
HINT: Consider
presenting symptoms
disease stage of severity
co-morbidity
differential diagnoses (spectrum
bias)
Can’t Tell
No
Comments:
6. Were the methods for
performing the test described in
sufficient detail?
Yes
HINT: Consider
was a protocol followed
Can’t Tell
No
Comments:
Section B: What are the results?
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7. What are the results?
HINT: Consider
are the sensitivity and
specificity and/or likelihood
ratios presented
are the results presented in
such a way that we can work
them out
Comments:
8. How sure are we about the results?
Consequences and cost of alternatives
performed?
HINT: Consider
could they have occurred by chance
are there confidence limits
what are they
Comments:
Section C: Will the results help locally?
Consider whether you are primarily interested in the impact on a population or individual level
9. Can the results be applied to
your patients/the population
of interest?
Yes
HINT: Do you think your
patients/population are so different from
those in the study that the results cannot
be applied, such as age, sex, ethnicity and
spectrum bias
Can’t Tell
No
Comments:
10. Can the test be applied to
your patient or population of
interest?
Yes
HINT: Consider
resources and opportunity costs
level and availability of expertise
required to interpret the tests
current practice and availability of
services
Can’t Tell
No
5
Comments:
11. Were all outcomes
important to the individual
or population considered?
Yes
HINT: Consider
will the knowledge of the test result
improve patient wellbeing
will the knowledge of the test result
lead to a change in patient
management
Can’t Tell
No
Comments:
12. What would be the impact of using this test on your patients/population?
Comments: