Comparison

The Chief Complaint vs DiagnosUs

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

Head to head
About

The Chief Complaint

This emergency medicine guide offers an algorithmic approach to over 50 common complaints. It provides decision support, links to medical resources, and includes a drug guide and calculators. A clinical community forum is also available for collaboration.

Highlights
  • Algorithmic approach to common ER complaints
  • Clinical decision support algorithms
  • Links to medical resources (PubMed, EM:RAP, etc.)
  • Emergency medicine drug guide
  • Medical calculators and scores
  • ESCAVO Clinical Community forum
Features
Read full description

The Chief Complaint app now includes access the new ESCAVO Clinical Community, a forum where clinicians can exchange ideas, ask questions and collaborate on sepsis and other clinical topics. How would you like to walk into the ER confident that you knew what to do, no matter what comes through the door? The Chief Complaint app uses an algorithmic approach to over 50 of the most common complaints encountered in emergency medicine. Never feel lost or overwhelmed again, not knowing what the next step in the work-up is. Not sure what tests to order or if the patient can go home? The Chief Complaint helps you answer all those questions and more! - Algorithm based approach to the most common emergency medicine complaints - Based on the #1 bestselling emergency medicine clinical guide "The Chief Complaint" - Used by the residents of LA County + USC emergency medicine program, one of the top emergency medicine programs in the world - Color coded by organ system for easy navigation - Exhaustively referenced to the most important studies and articles in emergency medicine (over 400 citations!) with direct links to PubMed abstracts for easy access to original sources - Over 60 high resolution clinical management and decision support algorithms - Direct subject-specific links to EM:RAP, Essentials of Emergency Medicine and theNNT.com for further resources and deeper dives on all subjects - Journal club feature allows you to dive deeper into the evidence basis of your decisions - Peer reviewed by leading physicians in emergency medicine - Important medical calculators and scores commonly used in the ER - Emergency medicine drug guide easily accessible right from the content pages - All content, including treatment algorithms, is built-in, network access is only required for content updates - Automatic content updating keeps app's contents constantly up to date free of charge The Chief Complaint is an invaluable resource for doctors, residents, medical students, nurses and other healthcare professionals working in emergency medicine and other acute care settings. Please send your feedback, questions or bug reports to info@escavo.com, we'd love to hear from you! Reviews: "The Chief Complaint is simply indispensable, carry it with me every shift. Excellent algorithms, concise, practical, clinically relevant explanations citing the current best-evidence for management decisions; without doubt Chief Complaint it is THE pocket Emergency Medicine reference to have with you at the bedside." -Manuel Montano, MD, PGY-3, LAC+USC EM Residency "...is really top notch. I really like how it organizes complaints in a flow pattern type way. This has allowed me to quickly adjust my decision making and makes it actually useful when I feel super pressured at work. The further detail located later has been helpful to one, get some good initial learning in and two, look to the resources cited for more in depth discussion." -David Benaron, UCSD Resident "Chief complaint is AWESOME...I think every single intern in the country should have one of these...SO COOL!" -James Grieme, UCSD Resident "The aptly named Chief Complaint is simply excellent. I really like the way it is laid out by cc and it's concise enough to be useful on a regular basis. I take it with me to every shift and would highly recommend it to anyone looking for a streamlined, functional, real-time guide for working up patients in the ED" -Nick Aldridge, UCSD Resident "... really something totally new in the medical education world. This app does something many have tried to do but few have achieved, which is to create an orienteering guide to the med-ed landscape while launching your thought processes AT THE BEDSIDE when confronted with a new undifferentiated and undiagnosed patient." -William "Billy" Mallon MD, Foreword

About

DiagnosUs

Engage with real medical cases to enhance your diagnostic skills and earn rewards. This educational game is designed for students and professionals to test their knowledge across various specialties and contribute to AI research.

Highlights
  • Analyze diverse medical cases
  • Improve diagnostic skills
  • Earn rewards for participation
  • Contribute to AI research
  • Study for medical exams
  • Regularly updated datasets
Read full description

DiagnosUs is an educational game for medical students, doctors, premed students, other healthcare professionals, and citizen scientists to analyze medical cases, improve their skills, and earn prizes! Participation is open to anyone, regardless of educational background. Players compete against their peers to hone their skills by analyzing cases in our datasets. At the same time, they contribute their knowledge to help advance artificial intelligence research. DiagnosUs is a wonderful supplement for classes, clerkships, and in preparation for exams such as the USMLE® Step 1 & 2 Clinical Knowledge (CK), NBME® exams, MBBS, NCLEX® exams, COMLEX Level 1 & 2, MCAT®, NEET-PG, and many more! The app promotes an engaging, dynamic platform to test anyone’s medical knowledge while simultaneously contributing to the development of crucial machine learning algorithms. Try a wide range of cases in subjects such as radiology, dermatology, USMLE® preparation, MCAT® preparation, NBME® preparation, NCLEX® preparation, ultrasound, neurology, cardiology, ophthalmology, emergency medicine, surgery, internal medicine, pediatrics, orthopedics, family medicine, gastroenterology, pathology, and pulmonology. Utilize the power of DiagnosUs to study interactively! New datasets are added regularly, so players can always keep learning! Learn medicine fast: see a wide range of cases! - Anatomy - Physiology - Auscultation to listen for pulmonary abnormalities - Dermatological images to identify melanoma, basal cell carcinoma, squamous cell carcinoma, psoriasis, dermatitis, and other skin conditions - EEG - EKG / ECG - USMLE® practice questions - MCAT® practice questions - NBME® practice questions - Chest X-rays to look for pneumonia and cancer - Musculoskeletal X-rays - Ultrasound identification problems - Fundus eye images - MRI - Whole Slide Pathology Imagery - Chest CT - Mammograms and much more! The rewards that participants can earn in the app are made possible by our research partners and customers, who are developing artificial intelligence related to image analysis. These research partners and customers subsidize our prizes because our app participants help analyze images from large datasets of our research partners and customers. After participants win rewards, they can tap on the Profile tab and tap on the icon in the top-left corner of the Profile screen. This screen then shows a log of all the participant's rewards, and they can withdraw their rewards to a payment account.

Screenshots

The Chief Complaint4 screens
DiagnosUs4 screens

Verdict

The call

The clearest difference is update cadence: DiagnosUs at fortnightly against The Chief Complaint's every 9 months. The Chief Complaint's advantage is monetization model (free vs free with in-app purchases) and review sentiment (88% vs 79%). On price, rating, ratings volume 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

On the App Store both sit at effectively the same score — 4.8 for The Chief Complaint against 4.8 for DiagnosUs. Both are backed by a comparable volume of ratings — 649 and 1K respectively. Written reviews are what separate them: 88% of The Chief Complaint's written reviews are positive against 79% of DiagnosUs's.

UpkeepUpdate frequency

The Chief Complaint ships an update every 9 months, DiagnosUs fortnightly. The most recent releases landed on July 17, 2026 and September 24, 2026 respectively.

Scorecard4 real differences · 6 level
The Chief Complaint versus DiagnosUs: the parameters behind the verdict, then further details
ParameterThe Chief ComplaintDiagnosUs
PriceFreeFree
Rating4.8 (649 ratings)4.8 (1K ratings)
Positive reviews88.0% of reviews — better79.4% of reviews
Number of ratings6491K — better
Update frequencyEvery 9 monthsFortnightly — better
AdsNoNo
In-app purchasesNoNo
MonetizationFree — betterFree with in-app purchases
DevicesiPhone, iPad, iPod — betteriPhone, iPad
Requires iOS11.0 — better16.0
Further details — not scored
Size157 MB42 MB
Age rating17+17+
DeveloperEscavo, IncCentaur Labs

Customer experience

The Chief Complaint

All ratings649 ratings
Positive96.3%
Neutral1.7%
Negative2.0%
Written reviews25 reviews
Positive88.0%
Neutral4.0%
Negative8.0%

DiagnosUs

All ratings1,015 ratings
Positive94.4%
Neutral1.9%
Negative3.7%
Written reviews228 reviews
Positive79.4%
Neutral10.1%
Negative10.5%

User reviews

The Chief Complaint

From 649 App Store ratings

What we love

  • 👍 Intuitive and easy to use interface
  • 🧠 Comprehensive differential diagnosis algorithms
  • 📚 Excellent educational resource for medical students and residents
  • 🎯 Clear, concise, and thorough clinical guidance
  • 🔗 Evidence-based recommendations with step-by-step approach

Room to improve

  • 📱 No iPad landscape mode support
  • ⚠️ Potentially outdated information (per one user)
  • 📖 Sparse coverage in some specialty areas (OB/GYN, toxicology)

DiagnosUs

From 1K App Store ratings

What we love

  • 💰 Earn money while learning
  • 🧠 Helpful for medical students and professionals
  • 🤓 Interesting and educational content
  • 👍 Fun and engaging app
  • 🤝 Responsive and helpful support team

Room to improve

  • 🐛 Bugs and technical issues (crashes, freezes, slow loading)
  • ⏱️ Time-consuming to compete and earn rewards
  • 🤖 Inconsistent or inaccurate AI-graded answers
  • 🤑 Difficult to earn significant amounts of money
  • 🔒 Withdrawal issues for some countries

Bugs and requests

The Chief Complaint

Reported bugs

1 issue
  • App crashes when deleting bookmarks

Requested features

3 requests
  • iPad landscape orientation support
  • Additional drug information in complaint categories
  • Expanded content for OB/GYN and toxicology sections

DiagnosUs

Reported bugs

4 issues
  • App crashes and freezes
  • Inaccurate or inconsistent grading of answers
  • Withdrawal and payment issues for some users
  • Compatibility problems with certain devices and OS versions

Requested features

5 requests
  • More diverse medical topics and case studies
  • Separate competitions for students vs. professionals
  • Ability to discuss and provide feedback on cases
  • Improved instructions and explanations
  • Compatibility with older devices and iOS versions

In-app purchases

None

The Chief Complaint

No in-app purchases

None

DiagnosUs

No in-app purchases

Questions

Is The Chief Complaint free?
The Chief Complaint is free to download, with no in-app purchases.
Is DiagnosUs free?
DiagnosUs is free to download, with no in-app purchases.
Which has better reviews, The Chief Complaint or DiagnosUs?
The Chief Complaint and DiagnosUs are both rated 4.8 out of 5 on the App Store, from 649 and 1K ratings respectively.
Do The Chief Complaint or DiagnosUs have ads?
Neither The Chief Complaint nor DiagnosUs shows ads.
Which is updated more often, The Chief Complaint or DiagnosUs?
The Chief Complaint ships an update every 9 months, and DiagnosUs fortnightly. Most recently, The Chief Complaint was updated on July 17, 2026 and DiagnosUs on September 24, 2026.

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