Risk-Based OQ Reduction Strategy for Medical System Board Modifications

Background

A central PCB within a medical system, operational for over seven years, required several design modifications to address long-standing performance issues. These included battery charging anomalies, hot-swap stability, obsolete components, and general yield improvements.

The system is deployed in four distinct configurations, each with slight hardware variations but a shared PCB platform.

The initial OQ (Operational Qualification) plan, defined by QA and V&V teams, mandated executing three full OQ lots per configuration, totaling 12 production lots (approximately 1,200 PCBs).

This would have significantly delayed implementation and consumed excessive production resources.

Initial Risk ConcernGiven the scope and nature of the proposed changes, a traditional OQ plan appeared disproportionate and inefficient.

A technical risk-based analysis was initiated to explore whether partial OQ combined with existing production controls would sufficiently validate the changes.

Technical Review and Risk Mitigation Actions

1. Obsolete Component Replacement Analysis

   • Obsolete components were replaced with functionally equivalent alternatives, using identical PCB footprints and reflow profiles.

   • Replacements were common across all four configurations.

   • No changes to the manufacturing process were introduced; SMT parameters remained unchanged.

   • Conclusion: Does not require configuration-specific OQ execution.

2. Hardware Modifications Review

   • Two additional design changes were implemented to improve functionality and system robustness.

   • These modifications were identical across all four configurations, both in circuit impact and manufacturing flow.

   • Conclusion: OQ testing on a single representative configuration (the most assembly-challenging) was deemed sufficient.

3. Manufacturing and Test Coverage Assessment

   • All PCBs are subject to 100% AOI and visual QC, per IPC-A-610 Class 3 standards.

   • Each unit undergoes a full ATP (Acceptance Test Procedure) with results logged by serial number.

   • All boards are traceable through final system-level testing where functional validation occurs.

   • Any deviations are linked to specific serials, allowing precise root cause analysis.

4. Cross-Functional Regulatory Alignment

   • QA, V&V, and RA teams were engaged in reviewing the proposed streamlined validation plan.

   • Given the robust in-process inspection and 100% ATP coverage, the team endorsed a partial OQ strategy—limiting formal validation to 30 units of the most complex configuration.

   • This approach leverages live production data for continuous performance monitoring and ensures immediate deviation detection.

Execution and Implementation Plan

• Revised OQ Plan:

  • Perform OQ only on one configuration (highest complexity for SMT assembly).

  • Limit validation lot to 30 units.

• In-Process Control Reliance:

  • 100% inspection, ATP, and functional testing maintained in routine production.

  • Traceability and defect detection continue via serialized data logging.

• Documentation Updates:

  • OQ protocol revised to reflect partial qualification strategy.

  • Risk assessment, justification, and traceability mechanisms documented and archived.

Conclusion

Based on:

• Uniformity of design changes across configurations,

• No change in manufacturing processes,

• Full ATP, AOI, and system-level testing applied to 100% of production units,

• Alignment with IEC 62366 and ISO 13485 requirements for risk-based validation, A partial OQ approach was approved.

This decision:

• Avoided unnecessary testing of 1,200 units,

• Maintained full product quality assurance through existing process controls.

• Enabled rapid implementation of performance and reliability enhancements.

The case exemplifies how targeted risk-based qualification, backed by rigorous in-line testing and traceability, supports both agility and compliance in medical device manufacturing.