Evidence based medicine is the use of mathematical estimates of the risk of benefit and harm (derived from high-quality research on population samples) to inform clinical decision-making in the diagnosis, investigation or management of individual patients.

In practice, it requires clinicians to contextualize the best available research evidence by integrating it with their individual clinical expertise and their patient’s values and expectations.

Diagnose is a medical app available for both Android and iOS that attempts to aid physicians in the difficult task of providing evidence based diagnosis through the use of pre and post-test probabilities and likelihood ratios.

User Interface

Diagnose is a simple to use medical app. It provides us with a list of diagnoses or conditions we can tap on. There is a search feature available to help us find conditions faster.

Once we are on the Condition screen we have the ability to adjust the pre-test probability by moving a slider. If we don’t adjust it, the pre-test probability supported by current literature is used. We then tap on the positive or negative findings from our workup so the post-test probability is calculated at the bottom of the app.

So let’s say you have a patient who you suspect might have COPD and you pull up Diagnose to make sure. We know that he’s been a smoker for the past 10 years but he smoked less than 70 packs year so we tap on Smoking ever to mark that as positive, then we tap on Smoking > 70 pack year until we marked that as negative.

He’s coughing a lot so we mark Coughing as positive as well. That put our post-test probability to 20%.


During our physical examination we notice that he’s wheezing a lot and has decreased breath sounds. Upon tapping those as positive findings, Diagnose updates the post-test probability.

Obviously, if you’re concerned for COPD, it’s important to have pulmonary function studies performed at sometime, and using this tool, it could lead you towards getting these studies done on your patient.

It’s a shame that the developers didn’t add small hints or reminders about pre- and post-test probabilities and likelihood ratios. It just assumes an understanding of pre- and post-test probabilities and likelihood ratios.

Having an intro tutorial to likelihood ratios would have helped make this app friendlier to physicians new to evidence based practice.


Evidence and literature used to support app

  • The app is well documented and contains references to source scientific papers.


  • Free


  • Great tool for evidence based practice
  • Excellent calculator system


  • Lacks info on likelihood ratios

Healthcare providers that would benefit from the app

  • Physicians in general as well as primary care practitioners


  • Diagnose is an excellent app for evidence based practice and its calculating system will surely be helpful.
  • If the developers would have added a small tutorial about evidence based medicine with a few lines on likelihood ratios, the app would be perfect.

Google Play Link
iTunes Link

Type of device used to review app – Moto X
App version – 1.0

Rating: (1 to 5 stars): 4/5

  • User interface – 3. UI is friendly
  • Multimedia usage – N/A
  • Price – 5. Great value for free
  • Real world applicability –4. Physicians will find this app to be a great tool