Computer Software Assurance: Understanding the FDA’s New Guidance

The FDA’s Computer Software Assurance (CSA) guidance marks a significant shift in how medical device manufacturers validate software used in production and quality systems.

Rather than treating every line of code with equal scrutiny, the new approach allows manufacturers to prioritise assurance activities based on risk, reducing unnecessary documentation while improving focus on systems that directly affect patient safety or product quality.

This guidance, published in 2025, replaces Section 6 of the General Principles of Software Validation (GPSV) and is designed to modernise how organisations demonstrate software reliability and compliance.

What Is Computer Software Assurance (CSA)?

CSA provides recommendations for applying software assurance to computers and automated data-processing systems used across manufacturing and quality management.

Where the previous guidance required a “validate everything” mindset, CSA introduces a risk-based model that recognises not all software functions carry the same level of risk.

The framework helps manufacturers:

• Focus resources where they have the greatest impact on safety and quality.
  
• Generate credible, objective evidence that systems work as intended.
  
• Meet FDA expectations under 21 CFR Part 820 without excessive documentation.
  

The Shift to a Risk-Based Approach

Under CSA, manufacturers assess intended use and process risk before determining the level of testing and documentation required.

Binary risk classification

Each software feature or function is evaluated to determine whether failure could compromise product quality or patient safety.

• If yes, it is categorised as high process risk.
  
• If no, it is not high process risk.
  

Organisations may also choose to apply more detailed risk gradations, low, medium, or high to better align with internal processes.

Practical implications

High-risk functions (e.g. automated sterilisation controls or device release systems) require structured verification, documented testing, and validation evidence.

Low-risk functions (e.g. scheduling tools or non-critical dashboards) may only need simplified verification and traceable test records.

This risk-based approach enables manufacturers to demonstrate compliance more efficiently, focusing assurance where it matters most.

What’s New in the 2025 FDA CSA Guidance

Expanded terminology and scope

The guidance now explicitly addresses modern architectures such as cloud-based software and service models, IaaS, PaaS, and SaaS. It clarifies how these systems integrate with manufacturing and quality processes, ensuring that assurance extends beyond on-premise tools.

Integration of vendor assurance

Manufacturers can now leverage vendor documentation and audits as part of their own assurance activities. This includes:

• Assessing vendor qualifications (e.g. ISO 13485 certification).
  
• Reviewing cybersecurity and data-integrity practices.
  
• Evaluating audit trails and change-management processes.
  

When vendor evidence is used, justification and evaluation must be documented in the Master Validation Plan (MVP).

Streamlined documentation

CSA promotes the least burdensome approach, replacing extensive manual documentation with digital evidence such as:

• Automated test scripts and screenshots.
  
• Electronic traceability logs.
  
• System-generated reports and version histories.
  

Targeted change control

Instead of revalidating entire systems after every update, CSA recommends impact assessments and risk-based change control. Only functions affected by the change require additional testing, reducing revalidation workload.

Comparison: From GPSV to CSA

Topic	GPSV Section 6 (Old Approach)	New CSA Guidance (2025)
Methodology	“Validate everything” regardless of impact.	Risk-based focus on high-impact functions.
Testing	Rigid, scripted testing protocols.	Flexible testing methods using exploratory, unscripted, or automated techniques.
Documentation	Heavy manual reporting burden.	Lean documentation with digital evidence and traceable automation.
Change control	Full revalidation after updates.	Impact-based assessment; partial revalidation when justified.
Scope	On-premise systems.	Includes cloud, SaaS, IaaS, and PaaS.

Implementation in Practice

A compliant CSA programme integrates risk evaluation into every step of the validation lifecycle.

Key actions for manufacturers

1. Define intended use and identify critical software functions.
   
2. Assess risk using binary or multi-tier models.
   
3. Determine testing rigour based on process risk.
   
4. Leverage vendor assurance where appropriate.
   
5. Capture objective evidence electronically.
   
6. Document logic and results in the Master Validation Plan.
   

By embedding CSA into existing quality processes, organisations can modernise their validation approach without compromising safety or compliance.

Benefits of Adopting CSA

• Reduced validation burden: Focus only on critical functions.
  
• Improved traceability: Automated systems generate real-time evidence.
  
• Regulatory alignment: Meets FDA and ISO 13485 expectations.
  
• Agility and scalability: Easier to integrate updates, new systems, or cloud-based tools.
  
• Audit readiness: Risk-based rationale clearly documented within the QMS.
  

Ultimately, CSA transforms software validation from a paperwork exercise into a strategic compliance activity that supports continuous improvement.

LFH helps medical device manufacturers modernise their validation processes under the FDA’s new Computer Software Assurance framework. From risk assessment and Master Validation Plan development to vendor qualification and audit preparation, our consultants ensure your QMS remains compliant, efficient, and future-ready.

FAQ