Comparison

Ferri's Best Test vs Derm DDx

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

Head to head
About

Ferri's Best Test

This medical reference app provides guidance on laboratory and imaging approaches for over 400 tests and 230 diseases. It features interactive flowcharts, IU units, and concise clinical material to aid in test selection and diagnostic skills.

Highlights
  • Over 400+ tests and labs
  • Guidance on radio-logic & laboratory approaches
  • 230+ common diseases
  • Interactive flowcharts
  • IU units for all tests
  • SmartSearch technology
Features
Read full description

"Try before you buy" - Download the FREE App, which includes sample content. An in-App purchase is required to unlock all content. Based on 4th print ed. Guidance on radio-logic & laboratory approaches. Over 400+ tests & labs. 230+ common diseases. Interactive flowcharts. IU units for all tests. Practical and concise, go-to reference for up-to-date clinical material on today's diagnostic testing and laboratory tests. Three convenient sections provide quick access to key information on clinical laboratory testing, diagnostic imaging, and diagnostic algorithms. Experienced author Dr. Fred Ferri uses a unique, easy-to-follow format to simplify complex information and help you choose the best test to supplement your clinical diagnostic skills. New to this Edition * Features a new appendix on when to use contrast agents in ordering CT and MRI scans. * Discusses new modalities including transient elastography (Fibroscan), CT enterography and CT enteroclysis. * Provides new comparison tables to easily evaluate the best test; new algorithms for evaluation of immunodeficiency and hematochezia; and new tables and illustrations throughout to improve your test selection. Key Features * Includes both lab and imaging tests for concise, convenient access to all diagnostic test options for more than 200 common diseases and disorders. * Includes essential information on indications, advantages, disadvantages, approximate costs, normal ranges, typical abnormalities, likeliest causes, and more. No internet connection is required to access the content after the initial download. Find information quickly using powerful SmartSearch technology. Search part of term for those hard to spell medical terms. Content licensed from printed ISBN 10: 0323511406 Content licensed from printed ISBN 13: 9780323511407 If you have any questions or comments, email us any time: customersupport@skyscape.com or call 508-299-30000 Privacy Policy-https://www.skyscape.com/terms-of-service/privacypolicy.aspx Terms and Conditions-https://www.skyscape.com/terms-of-service/licenseagreement.aspx Editor(s): Fred F. Ferri, MD, FACP Publisher: Mosby | Elsevier, Inc.

About

Derm DDx

This app provides visual, point-of-care guidance for diagnosing skin disorders. It features a large database of high-resolution images, allowing users to compare variations, zoom in, and access clinical history and treatment options for over 160 dermatologic conditions.

Highlights
  • 650+ high-quality dermatology images
  • Guidance for 160+ dermatologic conditions
  • Side-by-side image variations
  • Zoomable high-resolution images
  • Clinical history and treatment options
  • Cross-referencing to differential diagnoses
  • Full text search and custom notes
Features
Read full description

The Dermatology DDx app from Unbound Medicine delivers visual, point-of-care guidance for establishing the diagnosis of skin disorders. This powerful, photo-intensive database allows users to search, view side-by-side variations of each skin disorder, easily zoom in on any of the high-resolution images, and instantly link to similar conditions to ensure accurate diagnosis. Each entry also contains clinical history, physical findings, and treatment options. Features of Dermatology DDx include: • 650+ high-quality images presented with common variations in presentation • Point-of-care guidance for 160+ dermatologic conditions • Cross reference links to differential diagnoses • History and treatment within each entry • Appendix charting potencies of topical steroids • Highlight and make custom notes within entries • Full Text Search to find topics quickly • Favorites for ’bookmarking’ important entries Authors: by James G. Dinulos MD, M. Shane Chapman MD, Andrew Eugene Werchniak MD, Dorothea T. Barton MD, Thomas P. Habif MD Publisher: Elsevier Powered by: Unbound Medicine Unbound Privacy Policy: www.unboundmedicine.com/privacy Unbound Terms of Use: https://www.unboundmedicine.com/end_user_license_agreement

Screenshots

Ferri's Best Test4 screens
Derm DDx4 screens

Verdict

The call

The clearest difference is rating: Ferri's Best Test at 4.8 against Derm DDx's 4.3. Ferri's Best Test also leads on ratings volume (26 vs 6) and iOS requirement (13.0 vs 15.0). Derm DDx's advantage is ads (none vs shown). On price, update cadence, in-app purchases and monetization model 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. Ferri's Best Test sells 1 one-off in-app purchase and Derm DDx sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

ReceptionRating · Positive reviews · Number of ratings

Ferri's Best Test holds the better App Store score, 4.8 against 4.3. Both are backed by a comparable volume of ratings — 26 and 6 respectively.

UpkeepUpdate frequency

Ferri's Best Test ships an update every 6 months, Derm DDx every 5 months. The most recent releases landed on October 24, 2026 and October 30, 2026 respectively.

Scorecard4 real differences · 5 level
Ferri's Best Test versus Derm DDx: the parameters behind the verdict, then further details
ParameterFerri's Best TestDerm DDx
PriceFreeFree
Rating4.8 (26 ratings) — better4.3 (6 ratings)
Number of ratings26 — better6
Update frequencyEvery 6 monthsEvery 5 months — better
AdsYesNo — better
In-app purchasesYesYes
MonetizationFree with in-app purchasesFree with in-app purchases
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS13.0 — better15.0
Further details — not scored
Size149 MB10 MB
Age rating17+17+
DeveloperSkyscape Medpresso IncUnbound Medicine, Inc.

Customer experience

Ferri's Best Test

All ratings25 ratings
Positive92.0%
Neutral8.0%
Negative0.0%

Derm DDx

All ratings6 ratings
Positive83.3%
Neutral0.0%
Negative16.7%

In-app purchases

1 purchases

Ferri's Best Test

One-time1
  • Ferri's Best Test - Lab & Diag$40.99
1 purchases

Derm DDx

One-time1
  • Dermatology DDx$69.99

Questions

Is Ferri's Best Test free?
Ferri's Best Test is free to download, with in-app purchases available.
Is Derm DDx free?
Derm DDx is free to download, with in-app purchases available.
Which has better reviews, Ferri's Best Test or Derm DDx?
Ferri's Best Test is rated higher. Ferri's Best Test averages 4.8 out of 5 from 26 ratings, while Derm DDx averages 4.3 from 6 ratings.
Do Ferri's Best Test or Derm DDx have ads?
Ferri's Best Test shows ads; Derm DDx does not.
Which is updated more often, Ferri's Best Test or Derm DDx?
Ferri's Best Test ships an update every 6 months, and Derm DDx every 5 months. Most recently, Ferri's Best Test was updated on October 24, 2026 and Derm DDx on October 30, 2026.

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