Likelihood ratios in diagnostic testing

In evidence-based medicine, likelihood ratios are used for assessing the value of performing a diagnostic test. They combine sensitivity and specificity into a single metric that indicates how much a test result shifts the probability that a condition (such as a disease) is present. The first description of the use of likelihood ratios for decision rules was made at a symposium on information theory in 1954.^[1] In medicine, likelihood ratios were introduced between 1975 and 1980.^[2][3][4]. There is a multiclass version of these likelihood ratios^[5].