Diagnostic tests 4: likelihood ratios

part 3: positive and negative likelihood ratios of diagnostic tests

in the previous two parts of educational manuscript series in emergency, we explained some screening characteristics of diagnostic tests including accuracy, sensitivity, specificity, and positive and negative predictive values. in the 3rd  part we aimed to explain positive and negative likelihood ratio (lr) as one of the most reliable performance measures of a diagnostic test. to better underst...

Making sense of diagnostic test likelihood ratios.

Likelihood ratios: getting diagnostic testing into perspective.

In modern medicine, sophisticated laboratory tests and imaging studies are often emphasized at the expense of history and physical examination, rather than complementing clinical assessment. Ancillary testing often fails to advance the diagnostic process, and increases patient risk and the expense of medical care. The relative value of clinical evaluation and technological methods is rarely con...

Evidence Based Emergency Medicine Part 3: Positive and Negative Likelihood Ratios of Diagnostic Tests

Introduction: n the previous two parts of educational manuscript series in Emergency, we explained some screening characteristics of diagnostic tests including accuracy, sensitivity, specificity, and positive and negative predictive values (1, 2). In the 3rd part we aimed to explain positive and negative likelihood ratio (LR) as one of the most reliable performance measures of a diagnostic test...

Understanding diagnostic tests 2: likelihood ratios, pre- and post-test probabilities and their use in clinical practice.

UNLABELLED The sensitivity and specificity of a test cannot be used to estimate probability of disease in individual patients. They can, however, be combined into a single measure called the likelihood ratio which is, clinically, more useful than sensitivity or specificity. Likelihood ratios provide a summary of how many times more (or less) likely patients with a disease are to have a particul...