Comparison

Preop Eval vs Know HBV

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

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.

Highlights
  • Cardiac evaluation algorithm
  • Medication guidance (starting/stopping)
  • Surgery timing after cardiac events
  • Preoperative testing recommendations
  • Review for students and residents
  • Perioperative insulin management
Features
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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.

About

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.

Highlights
  • Chronic hepatitis B monitoring guidance
  • Antiviral treatment recommendations
  • WHO and AASLD guideline adaptation
  • Educational tool for healthcare professionals
  • Resource-limited country focus
Features
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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

Preop Eval4 screens
Know HBV4 screens

Verdict

The call

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

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

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.

UpkeepUpdate frequency

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.

Scorecard4 real differences · 6 level
Preop Eval versus Know HBV: the parameters behind the verdict, then further details
ParameterPreop EvalKnow HBV
PriceFreeFree
Rating5.0 (2 ratings) — better4.3 (3 ratings)
Positive reviews66.7% of reviews100.0% of reviews — better
Number of ratings23 — better
Update frequencyEvery 6 monthsEvery 4 months — better
AdsNoNo
In-app purchasesNoNo
MonetizationFreeFree
DevicesiPhoneiPhone, iPad, iPod — better
Requires iOS16.612.0 — better
Further details — not scored
Size15 MB67 MB
Age rating17+17+
DeveloperUnited Health Services, Inc.Hep B Moms

Customer experience

Preop Eval

All ratings2 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews12 reviews
Positive66.7%
Neutral8.3%
Negative25.0%

Know HBV

All ratings3 ratings
Positive66.7%
Neutral33.3%
Negative0.0%
Written reviews3 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

Preop Eval

No in-app purchases

None

Know HBV

No in-app purchases

Questions

Is Preop Eval free?
Preop Eval is free to download, with no in-app purchases.
Is Know HBV free?
Know HBV is free to download, with no in-app purchases.
Which has better reviews, Preop Eval or Know HBV?
Preop Eval is rated higher. Preop Eval averages 5.0 out of 5 from 2 ratings, while Know HBV averages 4.3 from 3 ratings.
Do Preop Eval or Know HBV have ads?
Neither Preop Eval nor Know HBV shows ads.
Which is updated more often, Preop Eval or Know HBV?
Preop Eval ships an update every 6 months, and Know HBV every 4 months. Most recently, Preop Eval was updated on September 30, 2026 and Know HBV on October 1, 2026.

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