The role of likelihood ratio in clinical diagnosis: Applicability in the setting of spontaneous bacterial peritonitis  Fernando Sierra, Diana Torres, Andrés Cárdenas  Clinical Gastroenterology and Hepatology  Volume 3, Issue 1, Pages 85-89 (January 2005) DOI: 10.1016/S1542-3565(04)00600-7 Copyright © 2005 American Gastroenterological Association Terms and Conditions

Figure 1 The Fagan nomogram. The use of this nomogram allows calculating the posttest probability of a disease from pretest probability and the LR. Reprinted with permission.5 Copyright © 1975 Massachusetts Medical Society. All rights reserved. Clinical Gastroenterology and Hepatology 2005 3, 85-89DOI: (10.1016/S1542-3565(04)00600-7) Copyright © 2005 American Gastroenterological Association Terms and Conditions

Figure 2 The art of clinical diagnosis. Clinical Gastroenterology and Hepatology 2005 3, 85-89DOI: (10.1016/S1542-3565(04)00600-7) Copyright © 2005 American Gastroenterological Association Terms and Conditions

Figure 3 Calculation of posttest probabilities based on different LRs. The posttest probability of SBP was calculated from the pretest probability of .2 (20%), but with different LR depending on the number of PMNs found in ascitic fluid. It is important to note that with the same pretest probability, different posttest probabilities are obtained depending on the LR given for the number of PMNs; sometimes it may even decrease the pretest probability of the disease (arrows). This highlights the usefulness of the LR in different clinical scenarios. (T. test, threshold to test; T. Treat, threshold to treatment). Clinical Gastroenterology and Hepatology 2005 3, 85-89DOI: (10.1016/S1542-3565(04)00600-7) Copyright © 2005 American Gastroenterological Association Terms and Conditions