EBM notebook
Making sense of diagnostic tests likelihood ratios
University of Oxford Department of Primary Health Care
Oxford, UK
Key Words: 2011
| The first 150 words of the full text of this article appear below. |
A smart mother makes often a better diagnosis than a poor doctor.
August Bier German, professor of surgery 1861–1949.
Statistical diagnosis is a mystery to many health practitioners.1 Information is often presented as test accuracy (sensitivity and specificity). However, at the bedside we need to know how a test result predicts the diagnosis or outcome of interest. Attempts to demystify approaches to diagnosis include the construction of 2 by 2 boxes, nomograms, and rules such as SpPin (with a Specific test the Positive Rules in) and SnNout (with a Sensitive test the Negative Rules out). In our teachings of evidence-based medicine, we have found an easier, intuitive way to interpret the results of diagnostic studies based on 2 elements: the likelihood ratio of the test and the pretest odds.
The likelihood ratio (LR) summarises information about the diagnostic test by combining information about the sensitivity and specificity. It tells
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
- Full Text
- Full Text (PDF)
- Submit a response
- Alert me when this article is cited
- Alert me when eLetters are posted
- Alert me if a correction is posted
Services
- Email this link to a friend
- Similar articles in this journal
- Similar articles in PubMed
- Add article to my folders
- Download to citation manager
- Request Permissions
Citing Articles
Google Scholar
PubMed
Bookmark with
Register for free content
The full back archive is now available for all BMJ Journals. Institutional subscribers may access the entire archive as part of their subscription. Personal subscribers will also have access to all content when logged in. Non-subscribers who register have free access to all articles published before 2006 right back to volume 1 issue 1. Register here to access the free archive of all BMJ Journals.
Don't forget to sign up for content alerts so you keep up to date with all the articles as they are published.
