Likelihood Ratios General Rules for Interpreting Likelihood Ratios (LRs) A LR greater than 1 increases the probability that the target disease is present, and a LR less than 1 decreases the probability that the target disease is present. LR Interpretation 10 Increases the pretest probability of disease by ~ 45% 5 Increases the pretest probability of disease by ~ 30% 2 Increases the pretest probability of disease by ~ 15% 1 No change in the likelihood of disease 0.5 Decreases the pretest probability of disease by ~ 15% 0.2 Decreases the pretest probability of disease by ~ 30% 0.1 Decreases the pretest probability of disease by ~ 45% Common Diseases, Tests and Likelihood Ratios Disease Test/Result Likelihood Ratio LR(+) 23.8 Acute cholecystitis Abdominal ultrasound LR(−) 0.05 LR(+) 23.8 Acute intracranial bleed Head CT LR(−) 0.05 ST elevation on at least one Acute myocardial infarction LR(+) 11.2 electrocardiographic lead LR(+) 17 Acute myocardial infarction Serial troponins LR(−) 0.04 LR(+) 87 Acute pancreatitis Lipase LR(−) 0.13 LR(+) 24.1 Acute pulmonary embolism Pulmonary CT angiography LR(−) 0.07 Alcohol abuse and dependence CAGE criteria: 3 of 4 positive LR(+) 13.3 LR(+) 24.2 Aortic stenosis (moderate to Late-peaking systolic murmur severe) LR(−) 0.3
Likelihood Ratios General Rules for Interpreting Likelihood Ratios (LRs) A LR greater than 1 increases the probability that the target disease is present, and a LR less than 1 decreases the probability that the target disease is present. LR Interpretation 10 Increases the pretest probability of disease by ~ 45% 5 Increases the pretest probability of disease by ~ 30% 2 Increases the pretest probability of disease by ~ 15% 1 No change in the likelihood of disease 0.5 Decreases the pretest probability of disease by ~ 15% 0.2 Decreases the pretest probability of disease by ~ 30% 0.1 Decreases the pretest probability of disease by ~ 45% Common Diseases, Tests and Likelihood Ratios Disease Test/Result Likelihood Ratio Acute cholecystitis Abdominal ultrasound LR(+) 23.8 LR(−) 0.05 Acute intracranial bleed Head CT LR(+) 23.8 LR(−) 0.05 Acute myocardial infarction ST elevation on at least one electrocardiographic lead LR(+) 11.2 Acute myocardial infarction Serial troponins LR(+) 17 LR(−) 0.04 Acute pancreatitis Lipase LR(+) 87 LR(−) 0.13 Acute pulmonary embolism Pulmonary CT angiography LR(+) 24.1 LR(−) 0.07 Alcohol abuse and dependence CAGE criteria: 3 of 4 positive LR(+) 13.3 Aortic stenosis (moderate to severe) Late-peaking systolic murmur LR(+) 24.2 LR(−) 0.3