6 Sensitivity , Specificity , and Predictive Value

Over the past decade, many clinicians have recognized th need to acquire an expanded clinical vocabulary and cot ceptual framework with which to interpret and act upo clinical information from the patient's history, the physic, examination, and the diagnostic laboratory . This expande vocabulary acknowledges the probabilistic nature of clinic events that occur consequent to diagnostic and therapeut strategies and thereby provides clinicians with the tools for more meaningful communication with colleagues and p ; tients . In essence, this approach addresses the uncertainty inherent in the information used to make diagnostic an therapeutic decisions, and its use permits a more explic approach to making decisions concerning patient manage ment. As the medical student progresses through the clinic years and beyond, he or she undoubtedly will hear state ments couched in the "old vocabulary." Statements such , "In our hands complications with this test are rare," "splenomegaly nomegaly is often present in this disorder," and "if the exercise test is positive, then this patient most likely h : coronary disease" are vague and leave room for variable interpretation . Terms such as "rare," "often," and "mo likely" have different meanings for different listeners an therefore are limiting if one is attempting to communicate precisely . Perhaps students also will hear statements couche in the "new" clinical vocabulary . Statements such as "The risk of death from this procedure has been reported i several series to range from 1 to 5%," "splenomegaly reportedly present in about 40 to 50% of patients with th disease," and "if the exercise test is positive, then I belies the patient has a 70 to 90% chance of having serious co onary artery disease" are used to replace the vague term nology. This chapter is an introduction to this new vocabulai using a clinical vignette about a patient with a commo health problem, chest pain . We believe the concepts inhe ent in this expanded framework and vocabulary are usefi tools in the everyday practice of medicine .