# Ferri's Best Test vs Derm DDx

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.

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.

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.

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.

## The numbers

| Metric | Ferri's Best Test | Derm DDx |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.8 (26 ratings)](https://appshunter.io/ios/app/ferris-best-test-lab-guide/id1243450037/reviews)** | [4.3 (6 ratings)](https://appshunter.io/ios/app/derm-ddx/id6499524221/reviews) |
| Number of ratings | **26** | 6 |
| In-app purchases | Yes | Yes |
| Ads | Yes | **No** |
| Update frequency | Every 6 months | **Every 5 months** |
| Monetization | Free with in-app purchases | Free with in-app purchases |
| Size | 149 MB | 10 MB |
| Requires iOS | **13.0** | 15.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 17+ | 17+ |
| Developer | [Skyscape Medpresso Inc](https://appshunter.io/developer/818609416) | [Unbound Medicine, Inc.](https://appshunter.io/developer/300420400) |

## What reviewers say

### Ferri's Best Test

[App page](https://appshunter.io/ios/app/ferris-best-test-lab-guide/id1243450037)

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:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Ferri's Best Test - Lab & Diag | $40.99 | one-time |


### Derm DDx

[App page](https://appshunter.io/ios/app/derm-ddx/id6499524221)

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:** macOS Compatibility, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Dermatology DDx | $69.99 | one-time |


## Frequently asked 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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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*