DIAGNOSTIC PERFORMANCE ANALYSIS (PART 1)
The primary purpose of a screening test is to rule out a disease or a clinical condition of interest to put less demand on the healthcare system and less discomforting for patients as it is usually less invasive, less dangerous, user-friendly and inexpensive. The question is, how do we know that a screening test is reliable and, therefore, safely applicable in clinical settings? The short answer is the predictive ability of a screening test must be inspected to what degree it corresponds to the reference standard to diagnose the condition. For example, if the hypothesis is testing the reliability of ECG to diagnose a STEMI, the ECG features must be analysed in relation to the angiogram outcome, which is considered the reference standard test to detect a complete obstruction of the coronary vessel. In other words, the ‘reference standard’ represents a test that provides authoritative and definitive proof that a condition of interest is present. The typical analysis to determine the...