STI Tx Guide vs Diagnosaurus® DDx
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
STI Tx Guide
Provides healthcare professionals with up-to-date, evidence-based recommendations for the prevention, diagnosis, and treatment of sexually transmitted infections. Features include clinical care guidance, sexual history resources, and patient materials for effective patient management.
- STI prevention recommendations
- Diagnosis guidance
- Treatment protocols
- Clinical care assistance
- Sexual history resources
- Patient management tools
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The new app offers quick and easy access to streamlined STI prevention, diagnosis, and treatment recommendations. The user-friendly interface includes more clinical care guidance, sexual history resources, patient materials, and other features to assist with patient management. The STI Treatment (Tx) Guidelines mobile app serves as a quick reference guide for doctors and related parties on the identification of and treatment for sexually transmitted diseases (STDs). The full STI Treatment Guidelines (cdc.gov) can be accessed at https://www.cdc.gov/std/treatment-guidelines/default.htm. The guidelines provide current evidence-based prevention, diagnostic and treatment recommendations that replace the 2015 guidance. The recommendations are intended to be a source for clinical guidance. Healthcare providers should always assess patients based on their clinical circumstances and local burden. DISCLAIMER THE MATERIALS EMBODIED IN THIS SOFTWARE IS PROVIDED TO YOU "AS-IS" AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL THE CENTERS FOR DISEASE CONTROL AND PREVENTION (CDC) OR THE UNITED STATES (U.S.) GOVERNMENT BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT, SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND, OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION, LOSS OF PROFIT, LOSE OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF THIRD PARTIES, WHETHER OR NOT CDC OR THE U.S. GOVERNMENT HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE POSSESSION, USE OR PERFORMANCE OF THIS SOFTWARE.
Diagnosaurus® DDx
This medical reference tool assists healthcare professionals in performing differential diagnoses quickly and confidently. It offers a searchable database of over 1,000 diagnoses, cross-referenced for related conditions, and allows users to save favorite entries and make custom notes.
- Over 1,000 differential diagnoses
- Search by organ system, symptom, or disease
- See Related DDx feature
- Save favorite entries
- Highlight and make custom notes
- Universal Index Search
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** Top-Selling App Used by Tens of Thousands of Health Professionals, Worldwide ** ABOUT DIAGNOSAURUS DDX This quick-reference tool helps healthcare professionals perform differential diagnosis with speed and confidence at the point of care. With Diagnosaurus you can quickly search over 1,000 diagnoses by organ system, symptom, or disease, or you can view all entries. Use the valuable “See Related DDx” feature within each entry to consider alternative diagnoses and quickly link to those entries. The convenient “Favorites” feature allows you to save specific searches and bookmark in your personal archive. FEATURES • More than 1,000 differential diagnoses • Highlight and make custom notes within entries • Entries organized in quick-read format • “See Related DDx” links to other potential diagnoses • Disease, symptom, and organ system indexes • “Favorites” for bookmarking important entries • Universal Index Search to help find answers fast Author: Roni F. Zeiger, MD Publisher: McGraw-Hill Medical Powered by: Unbound Medicine
Screenshots
Verdict
The clearest difference is rating: Diagnosaurus® DDx at 4.8 against STI Tx Guide's 3.5. Diagnosaurus® DDx also leads on ratings volume (2.5K vs 36) and review sentiment (53% vs 36%). STI Tx Guide's advantage is in-app purchases (none vs 1) and update cadence (every 2 months vs every 10 months). On price, ads and iOS requirement 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. Diagnosaurus® DDx sells 1 one-off in-app purchase. STI Tx Guide asks for nothing beyond the download.
Diagnosaurus® DDx holds the better App Store score, 4.8 against 3.5. That said, the two scores are not equally well evidenced: Diagnosaurus® DDx has 2.5K ratings behind it against 36, so its average is the more settled of the two. Written reviews point the same way: 36% of STI Tx Guide's written reviews are positive against 53% of Diagnosaurus® DDx's.
STI Tx Guide ships an update every 2 months, Diagnosaurus® DDx every 10 months. The most recent releases landed on October 23, 2026 and October 24, 2026 respectively.
| Parameter | STI Tx Guide | Diagnosaurus® DDx |
|---|---|---|
| Price | Free | Free |
| Rating | 3.5 (36 ratings) | 4.8 (2.5K ratings) — better |
| Positive reviews | 35.7% of reviews | 53.2% of reviews — better |
| Number of ratings | 36 | 2.5K — better |
| Update frequency | Every 2 months — better | Every 10 months |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Free — better | Free with in-app purchases |
| Devices | iPhone, iPod | iPhone, iPad, iPod, Mac — better |
| Requires iOS | 15.0 | 15.0 |
| Further details — not scored | ||
| Size | 36 MB | 19 MB |
| Age rating | 12+ | 17+ |
| Developer | Centers For Disease Control and Prevention | Unbound Medicine, Inc. |
Customer experience
STI Tx Guide
Diagnosaurus® DDx
Bugs and requests
STI Tx Guide
Not enough reviews yet to summarise bugs or requests.
Diagnosaurus® DDx
Reported bugs
3 issues- Subscription issues and inability to restore purchases
- Blank pages and non-functional content
- Compatibility issues with newer iOS versions
Requested features
5 requests- Add ability to edit or add custom differential diagnoses
- Improve search functionality and navigation
- Provide more detailed information on conditions
- Integrate with other medical resources and databases
- Improve support for older devices and iOS versions
In-app purchases
STI Tx Guide
No in-app purchases
Diagnosaurus® DDx
- Diagnosaurus DDx$4.99
Questions
Is STI Tx Guide free?
Is Diagnosaurus® DDx free?
Which has better reviews, STI Tx Guide or Diagnosaurus® DDx?
Do STI Tx Guide or Diagnosaurus® DDx have ads?
Which is updated more often, STI Tx Guide or Diagnosaurus® DDx?
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