A REVIEW OF THE MCMURRAY TEST - DEFINITION, INTERPRETATION, AND CLINICAL USEFULNESS

Clinicians frequently use the results of clinical diagnostic tests to make decisions concerning patients. The intent of this paper is to rev iew the technical aspects and measurement properties of the McMurray t est and, more globally, to illustrate the impact that indiscriminate t est application has on test interpretation. The literature shows that diagnostic accuracy studies, which evaluate the test described by McMu rray, yield remarkably similar estimates of sensitivity (about 26%) an d specificity (about 94%) These rest characteristics are applied to th ree case scenarios to illustrate the impact that history-specific prev alence (ie., the likelihood a patient has the condition based on the h istory) has on the predictive values. The results show a high false po sitive rate when applied to patients who, based on the history, have a low pre-physical examination likelihood for the condition of interest and a higher false negative rate when applied to patients who have a high history-specific prevalence. Readers are warned that the exhausti ve examination approach effectively lowers the prevalence and results in a high false positive rate. The impact that the exhaustive approach has on increasing the false positive rate is universal to all diagnos tic investigations and is not unique to the McMurray test.