What you will learn
By the end of this topic, you should be able to decide when process validation is required, define a validation strategy, plan qualification and performance evidence, select representative conditions and maintain the validated state through monitoring and change control.
Validate when later verification cannot fully assure the result
Process validation is required when the resulting output cannot be fully verified by subsequent monitoring or measurement and deficiencies may become apparent only after use. Examples may include sterile processing, sealing, welding, moulding, coating, bonding and automated processes where destructive or incomplete inspection is unavoidable.
Validation provides evidence that a defined process, operated within controlled limits, can consistently deliver its planned result.
Document the decision for each process. High-risk processes may warrant validation even when some output inspection is possible, because inspection may not reveal every relevant property or latent defect.
Plan from product requirements and process risks
- Define the product characteristics and risk controls created by the process.
- Specify inputs, outputs, parameter ranges and acceptance criteria.
- Identify equipment, tooling, software, utilities, environment and personnel.
- Characterise sources of variation and credible worst cases.
- Define sample selection, lots, shifts, operators and statistical rationale.
- State responsibilities, deviations, approval and revalidation rules.
- Link routine monitoring to the validated operating window.
Qualify resources and establish the operating window
Installation
Equipment, utilities, safety, documentation and calibration are correctly established.
Operation
Controls, alarms and parameter limits operate across defined ranges and challenges.
Materials
Approved inputs and worst-case characteristics are understood.
Methods
Instructions, setup, inspection and test methods are controlled and suitable.
People
Operators and reviewers are trained and competent.
Environment
Relevant temperature, humidity, cleanliness and contamination conditions are controlled.
Terms such as IQ, OQ and PQ are common and useful, but the labels are less important than complete, risk-based evidence.
Demonstrate repeatable performance under routine conditions
Performance qualification should use approved inputs, representative equipment, trained operators and normal production instructions. Include relevant variability such as lots, cavities, shifts, sites and setup conditions. Challenge justified edges of the operating window without creating artificial evidence unrelated to routine use.
Predefine acceptance criteria and how deviations will be treated. Investigation may justify repeating an invalid run, but repeating until a pass occurs is not validation.
Match statistical evidence to the decision
A default of three batches is not a universal scientific justification. Use MTL-128 — Statistical Methods and Measurement Assurance to plan defensible quantitative evidence.
Validate software used in production and quality systems
Software that controls equipment, calculates acceptance, manages recipes, records results or supports quality processes should be validated for its intended use. Focus evidence on functions, data and failure modes that affect product quality or regulatory records.
Control configuration, access, interfaces, calculations, backups, audit trails where applicable and changes. Supplier testing may support—but does not replace—the organisation’s intended-use validation.
Maintain the validated state
Validation is not a one-time event. Monitor parameters, output characteristics, yield, alarms, maintenance, calibration and nonconformances. Periodically review whether the evidence and operating window remain representative.
Revalidation may be triggered by changes to product, material, supplier, equipment, tooling, software, site, environment, method or scale; adverse trends; unexplained failures; extended shutdown; or new knowledge. The scope can be proportionate when the impact assessment is sound.
Common misconceptions
“Three successful lots validate every process.”
Evidence must be based on process variation, risk, method and the claim—not a ritual number.
“Product verification and process validation are interchangeable.”
Verification confirms selected output; validation demonstrates that the process consistently achieves its planned result.
“A validated process cannot be changed.”
It can, but impact must be assessed and necessary qualification or revalidation completed before controlled implementation.
Authoritative external references
- ISO 13485:2016 — Medical devices — Quality management systems
- FDA — Quality Management System Regulation (QMSR)
- FDA — Quality and Compliance (Medical Devices)
Use current process-specific standards and guidance alongside the applicable quality-system requirements.
Validate the process logic, not a ceremonial number of runs
Connect product requirements, process risk, representative variation, capable measurement and routine monitoring into evidence that remains valid over time.