Preop Eval vs Know HBV
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Preop Eval
This app provides guidance for evaluating and preparing adult patients for non-cardiac surgery. It includes algorithms and resources on medication management, cardiac event timing, and preoperative testing, serving as both a reference and a teaching tool for medical professionals.
- Cardiac evaluation algorithm
- Medication guidance (starting/stopping)
- Surgery timing after cardiac events
- Preoperative testing recommendations
- Review for students and residents
- Perioperative insulin management
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Preop Eval organizes and presents much of the guidance that one needs in order to evaluate and prepare adult patients for non-cardiac surgery. It is based upon the guidelines on this topic from the American College of Cardiology, the European Society of Anaesthesiology, the American Society of Anesthesiologists, the Institute for Clinical Systems Improvement, the American College of Chest Physicians, and more (full references in the app). The app contains 1 algorithm and 3 resources: the cardiac evaluation algorithm, guidance on starting and stopping key medications in the perioperative period, guidance on timing of surgery after cardiac events, and guidance on preoperative testing. It also contains a review of preoperative evaluation mainly for students and residents. The app addresses such common questions as: - who needs bloodwork before surgery? - who needs an EKG or a CXR? - how do I handle patients on warfarin, clopidogrel, and DOAC's? - which patients need adjustment of perioperative insulin and diabetic meds, and how? - which active cardiac conditions preclude surgery? - how long after MI or stent should a patient wait before surgery? - are there adjustments to make on psych meds, rheumatologic meds, ACE's and ARB's? This app is written and intended for practicing physicians like internists, family physicians, and hospitalists; for resident physician trainees; and for medical students. In addition to being a reference, the algorithm is written to be a teaching tool by not just delivering an answer, but instead walking a physician through the evaluation process so that one learns that process along the way. As an educator and clinician, I am interested in feedback and I would be grateful for guidance on improving the tool.
Know HBV
This educational tool assists primary healthcare professionals in managing adults with chronic hepatitis B. It offers guidance on monitoring and recommends antiviral treatment based on WHO and AASLD guidelines. It is intended for healthcare providers and not for patient self-diagnosis or treatment decisions.
- Chronic hepatitis B monitoring guidance
- Antiviral treatment recommendations
- WHO and AASLD guideline adaptation
- Educational tool for healthcare professionals
- Resource-limited country focus
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The chronic hepatitis B Treatment Decision Tool for Adults is developed by the Asian Liver Center at Stanford University in response to the WHO Global Health Sector Strategy on Viral Hepatitis to increase treatment rates when indicated to at least 80% by 2030. The app is an educational tool intended for primary healthcare professionals particularly in resource-limited countries as a general guide in the monitoring of HBsAg positive adults, and when antiviral treatment would be recommended based on the guidelines adapted from the World Health Organization or from the American Association for the Study of Liver Diseases. This app provides general guidance to primary healthcare professionals and is not a substitute for the advice provided by specialists in the management of liver disease and chronic hepatitis. Any course of action recommended or suggested in this educational tool should not be undertaken by the healthcare professional without an evaluation of the patient’s condition and contraindications. The patient should be provided with information about hepatitis B facts, and the potential benefits and risks of antiviral treatment. The app is not intended for use by non-healthcare professionals or patients. Non-healthcare professionals or patients must seek a doctor’s advice in addition to using this app before making any medical decisions.
Screenshots
Verdict
The clearest difference is rating: Preop Eval at 5.0 against Know HBV's 4.3. Know HBV's advantage is review sentiment (100% vs 67%) and device support (3 vs 1). On price, ratings volume, update cadence and ads there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
Preop Eval holds the better App Store score, 5.0 against 4.3. Both are backed by a comparable volume of ratings — 2 and 3 respectively. Written reviews complicate that: 67% of Preop Eval's written reviews are positive against 100% of Know HBV's, so the app with the better star average is not the one people write more warmly about.
Preop Eval ships an update every 6 months, Know HBV every 4 months. The most recent releases landed on September 30, 2026 and October 1, 2026 respectively.
| Parameter | Preop Eval | Know HBV |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (2 ratings) — better | 4.3 (3 ratings) |
| Positive reviews | 66.7% of reviews | 100.0% of reviews — better |
| Number of ratings | 2 | 3 — better |
| Update frequency | Every 6 months | Every 4 months — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | Free |
| Devices | iPhone | iPhone, iPad, iPod — better |
| Requires iOS | 16.6 | 12.0 — better |
| Further details — not scored | ||
| Size | 15 MB | 67 MB |
| Age rating | 17+ | 17+ |
| Developer | United Health Services, Inc. | Hep B Moms |
Customer experience
Preop Eval
Know HBV
In-app purchases
Preop Eval
No in-app purchases
Know HBV
No in-app purchases









