Biomedical Diagnostics App

Designing an at-home testing experience in a startup environment

I designed a usability critical web application for at-home infectious disease testing, collaborating closely with engineers and chemists and leading multiple rounds of user research.

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[interface] screenshot of core features (for an ai developer tools)

Context

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This project focused on designing a web application that supports at-home and clinic-based testing for COVID-19, RSV, and influenza. The product needed to guide users through a sensitive, accuracy-critical process, often without prior medical experience, while also supporting repeated use in small clinical settings.

The work took place in a startup environment, where speed, ambiguity, and cross-disciplinary collaboration were constant. Usability was not just a design concern; it was essential to ensuring the product could be used correctly, confidently, and consistently by a wide range of users.

My Role

Human Factors Engineer / UX Designer

I worked as the UX designer on a small, cross-functional team alongside two software engineers, a mathematician, and two interns, reporting under the CTO. While decisions were made collaboratively, I had significant ownership over the application’s structure, user flows, and interaction design, and led the usability and research efforts throughout development.

The role required frequent collaboration beyond traditional UX boundaries, balancing design, technical feasibility, and scientific accuracy.

Colaborators

Chief Technical Officer
Software Engineers
Firmware Engineers
Chemists
Mathematicians
Marketing Mangers
Legal Specialists
USer Studies

Research & Validation

Given the high-stakes nature of at-home diagnostics, usability and comprehension were critical. Over several months, we conducted approximately five rounds of in-person user studies, with each round building on insights from the previous one.

Study Approach

In-person, moderated sessions
Participants received minimal instruction at the start
No intervention unless technical issues occurred
What we evaluated
  • Usability and comprehension
  • Application bugs and breakdowns
  • Whether users could complete the test accurately
Participants completed post-study surveys, providing additional qualitative insight
This approach allowed us to observe how users naturally interacted with the application, identify points of confusion or hesitation, and validate whether the experience supported accurate test completion under real-world conditions.

Key Insights

The studies revealed consistent patterns that informed how the experience needed to adapt across users and contexts.

Age-related accessibility challenges

Younger users generally moved through the app with minimal friction, while users 65+ struggled more with reading text and understanding next steps. This highlighted the need for clearer hierarchy, larger text, and more explicit guidance.

The primary flow wasn’t always followed

Users did not consistently move through the intended “happy path.” When they deviated, the experience often lacked clear recovery cues, revealing the need for stronger guidance and forgiving paths back to completion.

Different user types required different experiences

Distinct user groups had distinct needs:

  • Guest users needed a simplified experience without personal data
  • Clinics required faster, repeatable flows without full instructions each time
This reinforced the importance of adaptable flows based on context.

Device state required clearer feedback

Device state mattered more than expected. For example, users often missed that the device door needed to be closed before continuing, indicating the need for more prominent visual cues and feedback.

Synthesis

These insights made it clear that the experience needed to be explicit, forgiving, and adaptable, supporting different users, contexts, and behaviors without relying on perfect adherence to a single flow.

Design Response

Based directly on research findings, I led design updates that prioritized clarity, error prevention, and adaptability across different users and contexts.

Inclusive Design

Accessibility & Readability

  • Increased text size and contrast to improve legibility, particularly for older users
  • Simplified instructional language and visual hierarchy to reduce cognitive load
User Context

Adaptive User Flows

  • Introduced a guest mode with adjusted flows and reduced personal information
  • Supported clinic use cases with faster, repeatable paths and reduced instruction depth
User Guidance

Guidance & Error Prevention

  • Added clearer, more prominent icons and visual cues to reflect device state
  • Strengthened primary action buttons and step-by-step guidance
  • Improved recovery paths for users who deviated from the main flow
Compliance

Regulatory & Documentation Support

In parallel, I contributed to the Instructions for Use (IFU) for both the product and the application. This work required a high level of precision and close alignment with regulatory expectations, ensuring the interface and documentation reinforced one another.

Selected UX Design Highlights

Design Response Examples

[digital project] image of a graphic design on a screen (for a web design agency)
[background image] image of fashion inspiration board (for a clothing boutique)
image of a concept brainstorming area for game development

Constraints & Considerations

The design work was shaped by a set of non-negotiable constraints that directly influenced product decisions and priorities.

Regulatory requirements

In-depth analysis to understand user needs and inform design decisions for effective solutions.

Clinical readiness

A viable, usable product was required before clinical trials could begin, placing emphasis on core workflows over non-essential features.

Team and resource constraints

Engineering resources were limited, which required careful prioritization, close collaboration, and shared responsibility across disciplines.

Accuracy expectations

Accuracy goals were extremely high, with a target of at least 99% test result accuracy, demanding tight coordination between design, engineering, chemistry, and mathematics.

These constraints reinforced the importance of designing experiences that were simple for users, yet robust under real-world conditions.

Outcomes & Current Status

Highlights
  • Designed to reduce barriers to access while maintaining high diagnostic accuracy
  • PCR-based testing provides higher accuracy than many alternative testing methods
  • Supports both at-home and small clinic use cases

Current Status

The product remains in active development, with continued iteration and validation underway as part of clinical trials. The diagnostic device and supporting web application are designed to lower barriers to access while maintaining a high standard of accuracy and usability.

The companion application is available in app stores for clinical trial use and supports both at-home and clinic-based workflows. In parallel, the device is undergoing additional clinical trials to expand testing capabilities beyond COVID-19, RSV, and influenza, including ABCR, HPV, and MTB.

The project has received external support, including funding from the Gates Foundation, and continues to progress toward broader validation and future release.

Hardware Affordability

With a primary cost of around $250, this device is significantly more affordable than comparable PCR devices.

Result Turnaround

One hour result turnaround compared to 24+ hours for lab-based PCR testing

Clinical validation

Currently undergoing clinical trials

External funding

Backed by the Gates Foundation

Project visuals at a glance

Explore selected case study highlights below.

image of a concept brainstorming area for game development

App-Device Integration

A streamlined interface for improved user flow.

[interface] screenshot of collaboration interface (for a productivity tools business)
image of a collaborative game planning session
[interface] close-up of the ai legal tech company's software interface

Supporting Documentation

Documentation aligns physical and digital elements.

interface of task management module (for a productivity tools business)
[background image] image of fashion inspiration board (for a clothing boutique)

Design and human factors work by grant adams

Co-DX PCR Pro™ | software team | 2022

Project supported in part by funding from the Gates Foundation