More than 1,000 differential diagnoses are searchable by “symptoms,” “disease” and “organ system.” The web-based interface and the mobile apps are all derived from McGraw-Hill's AccessMedicine Quick Medical Diagnosis & Treatment by Roni F. Zeiger, M.D.

Diagnosaurus for iOS, Android and Windows Phone 8 currently costs $1.99, but it is free for Palm, Blackberry and Windows Mobile. It is also free on the web at Access Medicine.

Features

• 1,000+ quick-read differential diagnoses
• Etiology section for determining cause of conditions
• Disease, organ system, and symptoms indexes for fast navigation
• Universal Index Search to help find terms across all indexes
• “Favorites” for bookmarking important entries
• “See related DDx” section with direct links to alternate entries
• Search feature (mobile App only)
• Periodically updated with new information
• Links to related symptoms and diagnoses
  
  

Utility & Navigation

The mobile iOS app works quickly and intuitively. Every tap responds instantaneously and search results appear immediately.

The list of diseases, organ systems or symptoms is displayed similarly to how contacts are shown on the iPhone. Each entry is displayed alphabetically on the right hand side so you can “jump” from A to Z without having to scroll or search.

Users of the Android version report similar functionality of the interface and navigation. However, a key difference between the web-based and mobile versions is the lack of a search function on the less intuitive web-based version (the search function covers the entire AccessMedicine website).

Clinicians will find the “favorites” feature (a single tap on the star icon) a helpful command for bookmarking symptoms or diagnoses. Deleting entries from the “favorites list” is as simple as tapping the “edit” button or swipe your finger over the entry and a delete button will appear. However, the app does not synchronize “favorites” between devices. Thus, if you create a list of favorites on your iPhone, there is no way to view that list on your iPad or vice versa.

Diagnosaurus downloads all of its data so that everything functions without a Wi-Fi or cellular data connection. This is especially useful in clinics or hospitals when Internet connections can be unreliable. A notification is sent when McGraw-Hill updates the database. Updates are downloaded within the app and install quickly.

Content

It is important to remember that Diagnosurus DDx is intended to help clinicians start the process of formulating a differential diagnosis, not to make the actual diagnosis. There also has been criticism (on message boards and in app stores) about the lack of clarity between “etiology” and “differential.” On the Diagnosaurus website, under the tab “instructions,” the following clarification is provided:

“In medicine, the terms ‘differential diagnosis’ and ‘etiology’ often overlap. They are sometimes distinct and sometimes synonymous. In Diagnosaurus, ‘DDx’ is generally used when either term can apply. However, many entries have both an etiology list and a DDx. In these cases, the etiologies are the possible causes of the condition, while the DDx is the list of alternative diagnoses. For consistency, etiology is always listed before DDx. A few entries also have a list of ‘associated conditions’ or ‘types.’ To navigate between these headings, you can tap the lower half of the screen to scroll down and skip to the next screen, use the pull-down menu, or use the up and down arrows to the right of the headings.”

In the mobile app (and somewhat similarly on the web-based version), every entry is linked to related entries by way of the “See Related DDx” feature. For example, while viewing the DDx of “molluscum contagiosum,” you may wish to see the related DDx of “papules and nodules.”

This feature also helps label a patient’s presenting syndrome and thus leads you to the best differential diagnosis. In the example above, if the skin bumps reminds you of warts, you might start with the “warts, non-genital” entry and then link to the differential diagnosis of “molluscum contagiosum” (among other possibilities).

How to Make the App Better

Relatedly, some users have criticized Diagnosaurus for providing a “laundry list” of possible diagnoses without prioritizing the differentials. Users, (and other reviewers) have commented that one way to make this app more useful is to present potential diagnoses by prevalence, incidence or likelihood.

A medical student who assisted with this review pointed out that a list of key bullet points below the diagnosis could help differentiate among the choices and would make Diagnosaurus a better tool for the aspiring clinician. These issues not withstanding, Diagnosaurus has been used successfully by thousands of medical students and practicing clinicians as a quick differential reference while studying, in problem-based learning sessions and during clinical practice.

Karen M. Rider, M.A. is a freelance writer who specializes in wellness, health psychology and healthcare news. In addition to writing for print and digital publications, Karen writes marketing content for health and wellness practitioners across a variety of specialties.