Diagnostic tests play an important part in both clinical and research fields. With a great number of statistical methods, different measurement parameters have been applied to different diagnostic tests. Selecting the appropriate measurement parameters is of the utmost importance for clinicians and researchers in their studies. This paper is aimed to help the clinicians and researchers to have a comprehensive understanding of the right measurement parameters, interpretation of the statistical outcomes accurately in their researches, and evaluation of the diagnostic tests objectively, with an example of the study on magnetic resonance arthrography applied to the diagnosis of intraarticular adhesions of TMJ. The measurement parameters include sensitivity, specificity, accuracy, predictive value, prevalence, likelihood ratio, and receiver operator characteristic curve.