Accuracy should be evaluated in relation to patient outcomes and the population context
Publication of the STARD paper, on standards for reporting of studies
of diagnostic accuracy, should ensure increased attention to the problems
of poor diagnostic research. Increased awareness of reporting of accuracy
studies should lead to better study designs and hence improve the evidence
base for diagnostic tests.
However, accuracy is but one aspect of assessing diagnostic tests.
Other evidence is required for determining the clinical utility of a test
- reproducibility, effectiveness and cost-effectiveness. A test is not
robust if not reproducible, yet evidence is often lacking. The effect of
test accuracy on patient outcomes is crucial, but the size of effect and
the optimum balance between sensitivity and specificity depends on the
context in which the test is used. Decisions about patient management may
be based on a test alone, for example with a screening test, or be part of
a battery of tests. For a screening test, in populations with a very low
prevalence of disease, false negatives are highly undesirable. With
additional information about a patient, reducing false positives may
become more important.
Whilst it may not be possible to provide comprehensive information
for established diagnostic tests, thorough appraisal of new tests should
include their relation to patient outcomes.
Improved reporting of accuracy studies is an excellent first step,
since currently new tests can be introduced with little evidence, unlike
the rigorous evaluation required for a new drug. However, we should be
moving to a staged evaluation for new tests, especially for population
screening, that adds evidence of effect on clinical, cost and personal
outcomes to measurement of the basic parameters of sensitivity,
specificity and reproducibility. This demands additional evaluative
methodology including clinical trials and mathematical modelling beyond
the studies discussed by the STARD group.
Competing interests:
None declared
Competing interests:
No competing interests
15 January 2003
David Jenkins
Professor of Pathology
Elaine Bentley
University of Nottingham, Queen's Medical Centre, Nottingham, NG7 2UH
Rapid Response:
Accuracy should be evaluated in relation to patient outcomes and the population context
Publication of the STARD paper, on standards for reporting of studies
of diagnostic accuracy, should ensure increased attention to the problems
of poor diagnostic research. Increased awareness of reporting of accuracy
studies should lead to better study designs and hence improve the evidence
base for diagnostic tests.
However, accuracy is but one aspect of assessing diagnostic tests.
Other evidence is required for determining the clinical utility of a test
- reproducibility, effectiveness and cost-effectiveness. A test is not
robust if not reproducible, yet evidence is often lacking. The effect of
test accuracy on patient outcomes is crucial, but the size of effect and
the optimum balance between sensitivity and specificity depends on the
context in which the test is used. Decisions about patient management may
be based on a test alone, for example with a screening test, or be part of
a battery of tests. For a screening test, in populations with a very low
prevalence of disease, false negatives are highly undesirable. With
additional information about a patient, reducing false positives may
become more important.
Whilst it may not be possible to provide comprehensive information
for established diagnostic tests, thorough appraisal of new tests should
include their relation to patient outcomes.
Improved reporting of accuracy studies is an excellent first step,
since currently new tests can be introduced with little evidence, unlike
the rigorous evaluation required for a new drug. However, we should be
moving to a staged evaluation for new tests, especially for population
screening, that adds evidence of effect on clinical, cost and personal
outcomes to measurement of the basic parameters of sensitivity,
specificity and reproducibility. This demands additional evaluative
methodology including clinical trials and mathematical modelling beyond
the studies discussed by the STARD group.
Competing interests:
None declared
Competing interests: No competing interests