Test Research versus Diagnostic Research: Clinical Application and Interpretation

Many published diagnostic studies are better characterized as test research than as diagnostic research [1]. Often these studies include a group of patients with the target disease and a group of patients without this disease in whom the results of the index test are also measured. There is a difference between test research and diagnostic research. The objective of test research is to assess whether a single diagnostic test (index test) adequately can show the presence or absence of a particular disease; however, the aim of diagnostic research is that whether index test appreciably adds to the diagnostic information that is readily available in clinical care [2,3]. Thus, the authors must include all tests that are used to detect disease, and then estimate the added value of index test comparing to other tests. Not with standing its limitations, test research—focusing on estimating the accuracy of a single test may offer relevant information. Most notably, it is helpful in the developmental phase of a new diagnostic test, when the accuracy of the test is yet unknown. Furthermore, test research can be valuable in the realm of screening for a particular disorder in asymptomatic individuals. In this context, no test results other than the single screening test are considered [2].