The healthcare landscape is rapidly evolving, and software is not just supporting medical devices, it is a medical device. In such an environment, testing and validation is not just a technical checkpoint, it is a clinical imperative.

Medical software must be reliable, safe and very important, compliant. And testing is far more complex than in traditional software development. Testers must prove that the software performs consistently, safely and effectively under real-world conditions, while meeting strict international standards and regulations like IEC 62304 or ISO 13485.

This article explores the unique demands of testing medical software, from verification and validation to usability testing and clinical performance. Whether you’re a developer, quality manager, or regulatory affairs professional, understanding this process is essential to delivering not just functional software, but trustworthy, life-saving technology.

First, we have to establish what is testing and what is validation. They are often used interchangeably but they have very different meanings, especially in the eyes of regulators.

What is testing?

So, testing is a process conducted by QA engineers in which they verify if the software performs as intended according to its specifications and includes activities like testing to check functions or components, if the modules work together or confirm if the application altogether works correctly.

What is validation?

Validation is a step further in ensuring that software fulfills its intended medical purpose in the real world, involving demonstrating that the software meets user needs, clinical expectations, and regulatory safety standards. Validation includes actions like clinical evaluation, usability testing or risk management analysis.

Why does the difference matter?

For non-medical applications, passing tests may be enough. But for medical software, regulators like the FDA or notified bodies under EU MDR require documented validation that shows the software is suitable for its medical use and is not just technically functional.

Testing the medical software. Make sure to check all the phases.

Testing the medical software is not just a one-time task. It is a multi-phase process designed to discover issues at every level. Each of these phases have a distinct role in verifying that the software is bug free, reliable and ready for clinical use.

But let’s walk through the key phases:

1. Unit Testing

Unit testing is the foundation, and it involves testing individual components or functions of the software in isolation. The goal here is to confirm that each code unit behaves as expected, independently of the rest of the system.

2. Integration Testing

Once individual units are verified, integration testing checks how they work together, revealing problems like data mismatches, communication errors between modules, or unintended side effects, helping uncover logic gaps between software modules.

3.  System Testing

System testing is when QA engineers evaluate the complete, integrated software product against functional and non-functional requirements. At this stage, they simulate realistic usage and verify that the full system behaves accordingly. System testing can reveal bugs introduced by infrastructure, environment, or user behavior.

4. Verification and Validation (V&V)

In this phase, medical software testing diverges from standard tech development. Verification ensures that the software functions properly and validation is when the software fulfills its intended medical purpose in real-world scenarios. This phase often involves a formal test plan, reviewed and approved as part of a quality management system.

5. Usability Testing

Even perfectly functioning software can be unsafe if users misinterpret it. That’s where usability testing comes in. Usability testing is conducted with real users (e.g., clinicians, patients) and evaluates the UI design, clarity, workflow efficiency and potential usability errors.

6. Penetration Testing

When it comes to cloud-connected or mobile medical devices, cybersecurity is a critical part of testing. In this phase, QA engineers test the software for vulnerabilities, unauthorized access, or any data leakage possibility.

7. Clinical Evaluation or Real-World Validation (for SaMD)

If the software provides clinical value, like analyzing ECGs or supporting treatment decisions, it may require clinical validation. This step may involve trials, retrospective data analysis, or various studies.

This phase is particularly relevant for Software as a Medical Device (SaMD), where software is the product.

Risk-Based Testing: A regulatory imperative

Risk-based testing is a regulatory requirement in medical software development, emphasizing that not all features carry equal weight.

Standards like IEC 62304 and FDA guidance mandate that testing efforts be proportional to the risk a software failure could pose to patient safety, meaning that high-risk functionalities like those supporting diagnosis, treatment decisions or life critical alerts, must be tested more rigorously, to be well documented and validated.

This approach helps software development companies allocate resources effectively, reduce regulatory delays, and build safer, more trustworthy software.

Common Pitfalls and how to avoid them

Despite the commitment and their best intentions, development teams may stumble when it comes to testing and validating the medical software, leading to delayed product launches, regulatory rejections or compromise patient safety.

Below are some of the most frequent pitfalls and some advice on how to avoid them:

1. Incomplete traceability

Regulators expect full traceability from user needs to validation evidence.

Failing to establish clear links between requirements, tests, and results is a major compliance risk.

Advice: Use requirements management tools like Jira, Polarion, or Helix RM to maintain traceability throughout the development lifecycle.

2. Underestimating validation scope

Don’t assume that functional testing is enough. Regulators demand proof that the software works for its intended medical purpose in real-world conditions and with actual users.
Advice: Involve clinicians or end-users in usability testing, clinical validation, and human factors studies early in the process.

3. Insufficient Risk-Based Testing

Treat all test cases equally. In this way you avoid wasting resources and neglecting critical areas.

advice: Conduct formal risk analysis to focus validation efforts where failure could cause the most harm.

4. Weak Documentation

Even excellent testing can fail inspection if it’s not well documented.

Advice: Create a validation plan, document protocols and outcomes, and ensure test reports are complete and reviewable.

5. Security and Interoperability

Cybersecurity and system integration are often left to the end of development cycle, creating vulnerabilities and delays.
Advice: Test for cybersecurity threats and third-party system compatibility as early as possible.

Test for trust, not just for compliance

In the world of medical software, testing is not just about passing checks or ticking boxes, it’s about earning trust. Trust from regulators who must approve your product, trust from medical professionals who rely on your product in high-pressure environments, and, most importantly, trust from patients whose lives may depend on its accuracy and reliability.

A thorough testing process must ensure not only that your software works as intended, but that it fulfills its medical purpose safely and effectively. By embracing the full spectrum of testing, development teams can create software that meets the highest standards of quality and compliance.

In an industry where the cost of failure is measured in human lives, rigorous testing isn’t just a regulatory requirement, it’s a moral responsibility.

AROBS Engineering

With 20+ years of experience in delivering reliable medical software, AROBS Engineering managed to work with some of the most important players in the medical industry for whom our development teams have successfully developed many life-saving medical devices, including life-critical infusion pumps, robotic surgery solutions, and even cancer detection systems. Our teams are well-equipped to handle complex projects and deliver solutions that meet industry standards. Learn more about our expertise in developing medical software and devices.