Diagnostic test accuracy study refers to the type of research design used to judge the accuracy of a diagnostic tool or method for disease diagnosis. Its accuracy judgment is the result after comparing with the gold standard. Diagnostic tests can be used to evaluate the diagnostic effects of trials and are essential to guide clinical decision-making. the accuracy of diagnostic tests refers to the ability to distinguish different disease states, including sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, negative likelihood ratio, area under the curve (AUC) and other indicators, among which sensitivity and specificity are not affected by the prevalence of the target disease in the population to be diagnosed, which is convenient for the evaluation of tests and the comparison between different diagnostic tests, and is widely used.