In the final analysis, however, relative diagnostic accuracies of competing tests are not the ultimate measure of a test’s clinical value. The incremental value of a test is defined by how a test interacts with other available diagnostic approaches in terms of relative diagnostic accuracy, relative costs, feasibility, and patient risk or invasiveness. These measures of incremental value of the evaluated diagnostic tests were provided by only a small proportion of the study articles; only 2 of the 41 studies provided information on all four elements of incremental value.
Deficiencies in study design may be less concerning if an article clearly identifies and describes its methodologic limitations and emphasizes, if design flaws exist, that the evaluated test should not be introduced into clinical practice until additional investigations are performed. Canadian family pharmacy Source Only 14 of the 41 studies, however, stated that additional data were needed before their evaluated tests could be recommended for routine use. Also, only one study identified and discussed the impact of design flaws on study conclusions regarding the diagnostic accuracy of the reported test.
This study supports previous observations that relatively little attention has been directed toward applying standard methods to diagnostic test research and extends these observations to the field of test assessment in pulmonary medicine. Flawed methods in other fields have resulted in the introduction of diagnostic tests into clinical practice that later proved to have marginal clinical value, such as the dexamethasone suppression test for depression and serum carcinoembryonic antigen determinations for detecting colon cancer. Greater attention to the available resources to assist investigators in designing protocols for evaluating new diagnostic tests will improve the application of new diagnostic tests to pulmonary medicine and prevent the misdirection of health-care resources to poorly validated diagnostic approaches.