Institute:Office of National Coordinator (ONC) Workforce Training Curriculum
Component:The Culture of Health Care
Unit:Evidence-Based Practice
Lecture:Phrasing the clinical question
Harm and prognosis
Slide content:Using EBM to Assess Questions about Diagnosis Diagnostic process involves logical reasoning and pattern recognition Consists of two essential steps: Enumerate diagnostic possibilities and estimate their relative likelihood, generating differential diagnosis Incorporate new information from diagnostic tests to change probabilities, rule out some possibilities, and choose most likely diagnosis Two variations on diagnosis to be discussed: Screening Clinical prediction rules 4
Slide notes:4 This lecture discusses diagnoses, particularly the effectiveness of diagnostic tests. How can we use evidence-based medicine to assess questions about diagnosis? If we look at the diagnostic processthe process of evaluating a patient and forming a diagnosiswe see that it involves both logical reasoning and pattern recognition. Logical reasoning is the ability to take into account different symptoms to rule in or rule out possible diagnoses based on the frequency, duration, severity, and other characteristics of the symptoms. Pattern recognition, as it applies to diagnosis, is the ability to look at the patterns of symptoms that we commonly see in various diseases. The diagnostic process actually has two essential steps. Before we can begin talking about diagnostic tests, we have to enumerate all the diagnostic possibilities and estimate their likelihood. Diagnostic decision support systems generate a differential diagnosis not only of the possibilities but also of the likelihood of each possibility based on the data collected about the patient and his or her condition. The second step is to incorporate new information from diagnostic tests that affect the probabilities for different items of the differential diagnosis. We can then rule out some possibilities and choose the most likely diagnosis. In this lecture, we also discuss two variants on diagnosis. One is screening , which is the use of diagnostic tests to screen people who are healthy in an attempt to intervene early to alter the disease process. The second is clinical prediction rules , where many pieces of information, including diagnostic tests, are used to try to predict the presence or absence of a disease.