# ABG Expert vs OpenEvidence

The clearest difference is update cadence: OpenEvidence at weekly against ABG Expert's every 5 months. OpenEvidence also leads on ratings volume (12K vs 9) and chart position (#37 vs unranked). ABG Expert's advantage is review sentiment (100% vs 81%) and iOS requirement (13.0 vs 15.1). On price, rating, ads and in-app purchases there is nothing between them.

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

On the App Store both sit at effectively the same score — 4.8 for ABG Expert against 4.9 for OpenEvidence. That said, the two scores are not equally well evidenced: OpenEvidence has 12K ratings behind it against 9, so its average is the more settled of the two. Written reviews are what separate them: 100% of ABG Expert's written reviews are positive against 81% of OpenEvidence's.

ABG Expert ships an update every 5 months, OpenEvidence weekly. The most recent releases landed on October 20, 2026 and October 27, 2026 respectively.

## The numbers

| Metric | ABG Expert | OpenEvidence |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.8 (9 ratings)](https://appshunter.io/ios/app/abg-expert/id885575488/reviews) | **[4.9 (12K ratings)](https://appshunter.io/ios/app/openevidence/id6612007783/reviews)** |
| Number of ratings | 9 | **12K** |
| Positive reviews | **100.0% of reviews** | 81.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 5 months | **Weekly** |
| Monetization | Free | Free |
| Best chart rank | — | **#37** |
| Size | 2 MB | 95 MB |
| Requires iOS | **13.0** | 15.1 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 12+ | +17 |
| Developer | [Brian Dale Vander Werf MD Inc](https://appshunter.io/developer/1521935908) | [OpenEvidence Inc.](https://appshunter.io/developer/1761260627) |

## What reviewers say

### ABG Expert

[App page](https://appshunter.io/ios/app/abg-expert/id885575488)

This medical tool provides accurate and flexible acid-base analysis for healthcare professionals. It offers detailed explanations, customizable ranges, and advanced features like anion gap correction and A-a gradient adjustments for various patient conditions and locations.

**Highlights:** Validated accuracy with real-world testing, Plausibility checks for physiologically impossible data, Automatic anion gap correction with albumin, Detailed explanations with equations, Separate or combined analysis of ABG, anion gap, A-a gradient, Customizable normal ranges for anion gap and delta gap, Age and barometric pressure adjustments for A-a gradient, Support for SI and non-SI units, Color-coded results and differential diagnoses, Adjustments for chronic respiratory conditions

**Features:** macOS Compatibility

**In-app purchases:** none


### OpenEvidence

[App page](https://appshunter.io/ios/app/openevidence/id6612007783)

**Currently charting:** #37 Top Free · Medical (US App Store)

This app provides healthcare professionals with evidence-based clinical decision support and medical information. It acts as a search engine, sourcing answers from peer-reviewed literature and leading medical organizations to aid in high-stakes medical decisions at the point of care.

**Highlights:** Clinical decision support, Medical search engine, Sourced from peer-reviewed literature, FDA and CDC data integration, Partnerships with leading medical journals, Verified healthcare professional access

**Features:** Siri integration

**In-app purchases:** none

**What reviewers like**

- 🚀 Accurate and concise answers
- 💡 Provides references and sources
- 👍 Helpful for clinical practice
- 🚀 Efficient search and retrieval
- 👍 Invaluable quick reference tool

**What reviewers complain about**

- 🐛 App not working in latest update
- ⚠️ Requires specific prompts for complete information

**Reported bugs**

- App not working in latest update

**Requested features**

- Availability on MacBook
- Integration with clinical workflows and EMRs


## Frequently asked questions

### Is ABG Expert free?

ABG Expert is free to download, with no in-app purchases.

### Is OpenEvidence free?

OpenEvidence is free to download, with no in-app purchases.

### Which has better reviews, ABG Expert or OpenEvidence?

OpenEvidence is rated higher. ABG Expert averages 4.8 out of 5 from 9 ratings, while OpenEvidence averages 4.9 from 12K ratings.

### Do ABG Expert or OpenEvidence have ads?

Neither ABG Expert nor OpenEvidence shows ads.

### Which is updated more often, ABG Expert or OpenEvidence?

ABG Expert ships an update every 5 months, and OpenEvidence weekly. Most recently, ABG Expert was updated on October 20, 2026 and OpenEvidence on October 27, 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.*