The informative value of a diagnostic test determines its usefulness in discriminating between subjects with or without the suspected disease. Various indicators have been proposed for assessment of diagnostic test performance including sensitivity, specificity, ROC curve, predictive values, and diagnostics odds ratio. Likelihood ratios are useful indicators of diagnostic utility of a test. The purpose of this article is to describe and present the properties and advantages of the different indicators used to evaluate diagnostic tests for severe systemic infection in patients with febrile neutropenia.