In the development of new facilities, manufacturing lines, automated systems or critical equipment in regulated environments, delays and deviations are rarely due to inadequate technology. Most often, the origin is found in insufficient definition of requirements, incomplete verification in early phases or a lack of coherence between design, manufacturing and installation.
In sectors subject to Good Manufacturing Practices (GMP), such as pharmaceutical, biotechnological or advanced therapies, the robustness of the project does not depend solely on contractual compliance with the supplier, but on the correct integration of key technical milestones within a life cycle approach. In this context, the Design Qualification (DQ), the Factory Acceptance Test (FAT) and the Site Acceptance Test (SAT) are not simple administrative stages, but structural quality assurance and risk reduction mechanisms.
The lack of clarity about what each phase should include, its real scope and its relationship with IQ/OQ/PQ usually generates three common problems:
- Unnecessary overlaps between tests.
- Critical gaps detected too late.
- Confusion between technical verification and regulatory qualification.
This article analyzes in depth what each stage should cover, how they should be structured, and how to strategically integrate them into new projects to maximize compliance, efficiency, and regulatory defensibility.
The conceptual framework that gives meaning to DQ, FAT and SAT
Before analyzing each stage individually, it is essential to understand its fit within the system life cycle. Current guidelines, especially GAMP 5 (2nd Edition), ICH Q9 and ICH Q10, promote a risk-based approach and process knowledge.
From this perspective:
- The DQ belongs to the definition and design phase.
- The FAT is part of the pre-delivery verification.
- The SAT represents the verification after installation in a real environment.
- IQ and OQ formalize the regulatory qualification.
- PQ confirms performance under routine conditions.
When these phases are designed coherently, there is a logical progression:
- What is needed is correctly defined.
- It is verified that it is built as defined.
- It is confirmed to work correctly in your environment.
- Regulatory evidence is formalized.
If this logic is broken, the project becomes reactive instead of preventive.
Design Qualification (DQ): ensuring the design is correct before building
Real objective of the DQ
La Design Qualification no validate equipment or run operational tests. Its purpose is to confirm that the proposed design is suitable for its intended use before committing significant resources to manufacturing, purchasing or construction.
The key question that the DQ must answer is:
Does the proposed design meet the user-defined technical, regulatory and operational requirements?
If this question is not clearly answered and documented, the risk of late modifications increases exponentially.
Essential Elements a Robust DQ Should Include
| User Requirements Specification (URS) | The URS is the basis of the entire process. It must be:
The DQ must demonstrate traceability between each critical requirement and its reflection in the technical design. |
| Technical design review | Includes detailed evaluation of:
The analysis must confirm that the design allows the process to be operated in a safe, reproducible and GMP-compliant manner. |
| Regulatory compliance | The review must consider applicable regulations such as:
Aspects such as classification of areas, segregation of flows, materials in contact with product, accessibility for maintenance and cleaning strategy must be evaluated from the conceptual phase. |
| Risk Management Integration (ICH Q9) | A mature DQ incorporates formal risk analysis:
Early risk management reduces future deviations and reinforces regulatory defensibility. |
Consequences of poor DQ
A DQ treated as a documentary formality usually results in:
- Structural changes in advanced phases.
- Expensive modifications to FAT or SAT.
- Delays in qualification.
- Difficulties during inspections.
The DQ is the time to question the design. After, room for maneuver decreases drastically.
Factory Acceptance Test (FAT): verify before transferring risk
FAT strategic objective
The FAT is executed at the supplier's premises and confirms that the equipment or system has been constructed in accordance with the approved design and is operating correctly before shipping.
It does not replace IQ/OQ, but it does significantly reduce technical risks and subsequent delays.
What an effective FAT should include
| Functional verification |
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| Automation Review | In computerized systems, the FAT must cover:
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| Risk-based testing | The FAT should not be an exhaustive repetition of all possible tests. You must prioritize:
The risk-based approach optimizes time and resources without compromising robustness. |
| Documentation and traceability | A solid FAT generates:
The FAT documentation must subsequently be integrated into the qualification strategy. |
Impact of a poorly executed FAT
When the FAT is superficial:
- Problems appear on SAT.
- The IQ/OQ becomes the corrective phase.
- Costs and delays increase.
- The position before audits is weakened.
A well-executed FAT conveys confidence; a weak one conveys uncertainty.
Site Acceptance Test (SAT): verify integration in a real environment
| Nature | The SAT is carried out after the installation of the equipment in its final location. Its objective is to confirm that the system works correctly in real conditions and integrated with its environment.
Here the focus is expanded: it is no longer just the team that is analyzed, but its interaction with:
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| Range | A robust SAT must contemplate:
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| Deviation management | The deviations detected must:
The SAT must leave the system in a technically stable and controlled state. |
Relationship between DQ, FAT and SAT: coherence and continuity
These stages are not independent or interchangeable: the DQ validates the conceptual design; The FAT verifies the manufacturing and the SAT confirms the installation and integration.
When there is clear traceability between URS, risk analysis, DQ, FAT and SAT, late changes are reduced, formal qualification is facilitated, regulatory defensibility is improved and start-up times are optimized.
The absence of documentary and technical continuity is one of the main weaknesses detected in audits.
Comparative table: DQ vs FAT vs SAT
| Aspect | DQ | FAT | SAT |
| Project timing | Design phase | Before shipment of the equipment | After installation in plant |
| Location | Technical office / documentary review | Supplier facilities | Customer facilities |
| Main objective | Verify that the design meets user and GMOP requirements | Confirm that equipment performs as designed before delivery | Confirm that the system works correctly in its real environment. |
| Key question answered | Is the design correct? | Was the equipment built correctly? | Does it work correctly in the plant? |
| Base documental | URS, functional and technical specifications, risk analysis | Approved design, technical specifications, control logic | Approved design, FAT results, actual installation conditions |
| Approach | Conceptual and technical | Functional and constructive | Operational and integrative |
| Includes GMP review | Yes (classification, materials, flows, regulatory compliance) | Partial (according to criticality) | Yes, in real operating context. |
| Includes functional tests | No (documentary and technical review) | Yes, in simulated/controlled environment | Yes, in a real environment. |
| Includes integration tests | No | Limited | Yes (SCADA, MES, services, upstream/downstream equipment) |
| Risk management (ICH Q9) | Design evaluation and technical decisions | Critical Test Prioritization | Impact evaluation in real environment |
| Relationship with IQ/OQ | Basis for subsequent qualification | Reduces incidences in IQ/OQ | Leave the system ready for IQ/OQ |
| common mistake | Treat it as a documentary procedure | Try too much or too little | Use it to correct design errors |
Conclusion
In new pharmaceutical projects, DQ, FAT and SAT are not simple contractual formalities or isolated documentary requirements. They are fundamental mechanisms for quality assurance, risk reduction and investment protection..
When each stage fulfills its specific function and is integrated within a risk-based life cycle approach, the result is a technically robust system, regulatory defensible and prepared for pass qualification and inspections.
Investing rigor in the early phases does not slow down the project. On the contrary, it prevents structural deviations that, once in production, are exponentially more complex and expensive to correct. For more information or to discuss your specific project, do not hesitate to contact with our team. We will be happy to accompany you from conceptual design to commissioning and final qualification.