Testing Guides
DQ, IQ, OQ and PQ: What Are They and How Do They Differ?
Every stage starts from the URS
Annex 15, clause 3.2, requires the specification for equipment, facilities, utilities or systems to be defined in a User Requirements Specification (URS) and/or a functional specification. The URS is the reference point throughout the qualification life cycle, and clause 3.3 requires compliance with the URS to be demonstrated during DQ.
What does each stage do?
| Stage | Question it answers | Cleanroom and HVAC example | Annex 15 |
|---|---|---|---|
| DQ (Design Qualification) | Does the design meet the URS and GMP? | Review of ISO Class/Grade zoning, pressure cascade and air change rates | 3.3 |
| IQ (Installation Qualification) | Is it installed to the design? | Check components against as-built drawings, collect manuals, calibrate instruments | 3.8–3.9 |
| OQ (Operational Qualification) | Does it operate within defined parameters? | Airflow, pressure, particles (at rest), temperature, humidity, HEPA leak test, upper and lower limits | 3.10–3.12 |
| PQ (Performance Qualification) | Does it perform consistently in real use? | Particles (in operation) and stability of conditions over the period of use | 3.13–3.14 |
Between DQ and IQ there may be a Factory Acceptance Test (FAT) and a Site Acceptance Test (SAT), clauses 3.4–3.7. Some of their results can replace repeat testing in IQ/OQ if justified and if it is shown that transport and installation did not affect function (clause 3.6).
How do IQ and OQ differ?
IQ checks what was installed. Under clause 3.9 this includes verifying installation of components, instrumentation, equipment, pipework and services against engineering drawings, collecting operating and maintenance instructions, calibrating instruments and verifying materials of construction. OQ, under clause 3.11, tests that the system operates as designed, including upper and lower operating limits or worst-case conditions.
OQ normally follows IQ, but depending on complexity some equipment can be qualified as a combined IOQ (clause 3.10). Completing OQ allows operating and cleaning procedures, training and maintenance requirements to be finalised (clause 3.12).
What happens after PQ?
Annex 15, clause 4.1, requires equipment, facilities, utilities and systems to be evaluated at an appropriate frequency to confirm they remain in a state of control. Clause 4.2 states that where requalification is done on a time basis, the period must be justified and the evaluation criteria defined. The principles of Annex 15 also require the impact of any planned change on the qualified state to be assessed.
Frequently asked questions
Can PQ be done together with OQ?
PQ normally follows successful IQ and OQ, but in some cases it may be performed in conjunction with OQ or process validation (Annex 15, clause 3.13).
What is a URS?
A document in which the user defines the system requirements. It is the starting point for DQ and is traced through every stage (Annex 15, clause 3.2).
Which stages does QV TEST cover?
All of them: DQ, IQ, OQ and PQ for cleanrooms and HVAC systems.
References
- PIC/S Guide to Good Manufacturing Practice for Medicinal Products, PE 009-16 (1 February 2022), Annex 15: Qualification and Validation, clauses 2.10, 3.1–3.14 and 4.1–4.2 (same text as EU GMP Annex 15)
- ISO 14644-1:2015 and ISO 14644-3:2019 (cleanroom test methods)
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