Pocket Guide to Diagnostic Tests-0838581358.pdf

20 Pocket Guide to Diagnostic Tests
begins the analysis by building a decision tree showing the important
elements of the decision. Once the tree is built, the clinician assigns
probabilities to all the branches. In this case, all the branch probabilities
can be calculated from (1) the probability of disease before the
test (pretest probability), (2) the chance of a positive test if the disease
is present (sensitivity), and (3) the chance of a negative test if the
disease is absent (specificity). Next, the clinician assigns utility values
to each of the outcomes.
After the expected utility is calculated, the clinician may identify
which alternative has the highest value by this analysis.
Although time-consuming, decision analysis can help to structure
complex clinical problems and to make difficult clinical decisions.
Evidence-Based Medicine
The focus over the past decade on evidence-based medicine stresses
the examination of evidence from clinical research—rather than intuition
and pathophysiologic reasoning—as a basis for clinical decision
making. Evidence-based medicine relies on systematic reviews of the
medical literature to inform clinical practice. Meta-analysis uses statistical
techniques to combine evidence from different studies.
Clinical practice guidelines are systematically developed statements
intended to assist practitioners and patients in making decisions
about health care. Clinical algorithms and practice guidelines are now
ubiquitous in medicine. Their utility and validity depend on the quality
of the evidence that shaped the recommendations, on their being kept
current, and on their acceptance and appropriate application by clinicians.
While clinicians are concerned about the effect of guidelines on
professional autonomy, many organizations are trying to use compliance
with practice guidelines as a measure of quality of care.
Computer Access to Medical Information
The development of medical information science and computer technology
now offer a vast amount of clinical information on CD-ROM or
over the World Wide Web.
REFERENCES
Dekay ML, Asch DA: Is the defensive use of diagnostic tests good for
patients, or bad? Med Decis Making 1998;18:19.
Detsky AS et al: Primer on medical decision analysis. (Five parts.) Med
Decis Making 1997;17:123.