Annex 15: Planning Requalification on a Risk Basis

The initial qualification has been passed, the system is running. But the validated state is not a permanent one: wear, modifications, software updates and creeping drift slowly move a system away from the point at which it was once released. This is exactly where requalification comes in, and this is exactly where many operations fail because of a rigid calendar logic that generates effort without creating assurance.

What Annex 15 actually requires

EU-GMP Annex 15 treats qualification and validation as a lifecycle, not as a one-time event. On requalification, the annex states that systems, facilities, utilities and equipment are evaluated at appropriate intervals to confirm that they remain under control. What is notable is what it does not say: a fixed period. Annex 15 deliberately names no rigid interval, but instead requires a justified, risk-based determination. This shifts the actual work from execution to justification.

Requalification is not revalidation

A common imprecision starts with the terms. Requalification refers to facilities, systems and equipment, that is, to the question of whether the equipment still conforms to its specifications. Revalidation refers to the process and its continued ability to deliver the required quality. Both share the same risk-based logic but address different objects. Anyone who conflates the terms plans imprecisely and risks responsibilities and scope falling apart in the audit.

Risk beats the calendar

A sound requalification plan derives the testing frequency from criticality. What matters is the GMP impact of the system, its stability in operation to date and the significance of ongoing monitoring.

• Systems with high product risk and little self-monitoring: tighter intervals.
• Well-monitored systems with a stable trend: longer intervals, backed by data.
• Triggers beyond the calendar: relevant changes, clusters of deviations, trend breaks, conspicuous maintenance findings.

Where continuous monitoring provides robust data, it can replace part of the periodic requalification or reduce its scope. This is not a shortcut but the consistent use of existing evidence.

The periodic review as a data source

Requalification does not fall into a void when the operation knows its history. Deviations, changes, calibration and maintenance results, together with the trends from monitoring, form the overall picture from which frequency and scope can be justified. A well-maintained periodic review provides exactly this input data. Without it, requalification remains a guess rather than an assessment.

Change control is half the plan

Most requalifications are not triggered by the calendar but by changes. A new spare part, a modified formulation, a control system update: every change needs an assessment of whether and to what extent requalification takes place. A clean change-control system that asks this question systematically prevents both blind spots and reflexive full testing.

Requalification is not a repetition of the initial qualification but a targeted confirmation of the validated state.

The scope: as much as necessary

Not every requalification means a complete DQ/IQ/OQ/PQ. Often a focused OQ or PQ on the critical functions is sufficient, supplemented by an assessment of the changes, deviations and maintenance that have occurred since the last qualification. What is decisive is that the scope is documented, justified and traceable against the original requirements from the URS. A common mistake is to carry out the requalification without including the intervening history. The evidence that the chosen test points actually address the relevant risks is then missing.

What counts in the end

A good requalification strategy is audit-proof because it is traceable: every frequency, every scope and every decision to forgo a test is justified by risk. It is also economical because it directs effort to where it creates assurance. In building such risk-based requalification concepts, Vispact provides support in operational plant engineering, from criticality assessment to a robust test plan.