Isabel DDx Companion FAQs

Isabel produces a list of relevant diseases, ranked in order of the degree of match between the disease presentations and clinical features, together with age, sex and region, entered by the user. Clinicians can review the Isabel list and access associated evidence-based content to work out which diseases they think are most probable for their patient. Isabel is there to support and assist the clinician in determining the differential and management plan. Isabel is about possibilities while clinical probability is determined by the clinician.
The clinical features can be entered in any order: ideally each one should be entered as an individual concept. Clinical features can be entered in free text or selected from the predictive text drop down list presented.
In addition to signs and symptoms, other clinical features such as abnormal test results, family history, vital signs, social history and comorbidities can be entered into Isabel. When entering lab values convert numerical data into the textual meaning for example, Hemoglobin 4.2mmol/l into ‘low hemoglobin’.
Since our launch in 2001, we have not received any reports of an increase in test ordering. In fact, Isabel should help you drive more appropriate test ordering and, most likely, save money on unnecessary tests.
On the contrary, Isabel is a tool that stimulates thinking about a patient’s presentation and assists with thoughtful consideration of the diseases being presented. Isabel does not tell you the diagnosis or tell you what to do next: it is just designed to help broaden the differential.
Isabel is used when you have a clinical uncertainty with a patient. For example, use Isabel on a patient seen in the ED who later returns with the same or worsening symptoms. Other examples are a patient seen in the practice who is not responding to treatment, a patient admitted with a non-specific diagnosis, or a patient where something just doesn’t add up!
Yes, Isabel will get used if it’s properly implemented and part of your institutional drive to improve quality and clinical decision making. Isabel is simply a tool to help you improve your clinical decision- making process and clinical reasoning skills. Members of the Isabel Healthcare team will also work with you after you start your subscription to help your institution drive adoption.

Download eBook

Isabel is made available to clinicians wherever and whenever they want it. In addition to using Isabel standalone or as a mobile app, it has also been integrated with most of the leading EMRs such as Cerner, Epic, NextGen, T-System, SystemOne, NextGen, etc. Isabel integration options include everything from simply launching the application, to HL-7 InfoButton integration or fully embedded using the Isabel API (Application Programming Interface) suite.
There are a number of differences that set Isabel apart from other tools. First, Isabel is built in a completely different way from other differential tools. It works by applying pattern recognition software onto a database of over 10,000 disease and causative drug presentations. Most other tools rely on a limited decision tree architecture making them much slower to use with more limited result options. In addition, no other tool can boast Isabel’s combination of accuracy, speed and ease of use with the ability to handle complex clinical cases across all specialties while at the same time being integrated into the clinician’s workflow.
There is an extensive body of validation studies supporting the use of Isabel. Recent RCT (Randomized Control Trial) studies show that Isabel substantially increases clinicians’ clinical reasoning skills.

If you have any questions that were not answered by the above, please send an email to:

Contact Us

If you would like learn more about Isabel, discuss partnering, write about us or just report a problem then please get in touch.

Contact Us

Get Isabel Now

Individual subscriptions available here. Fully compatible on all devices.


Get the White Paper

Download our White Paper to learn “How and Why to Improve Diagnosis Decision Making”

Download White Paper