Never Change Sampling Procedures Mid-Study Without Documented Justification

Do Not Change Sampling Procedures During Ongoing GMP Studies

Remember: GMP mandates that sampling procedures remain fixed throughout the study. Any deviation must be pre-approved by QA and supported by documented justification.

Why This Matters in GMP

Sampling is a critical component in the verification of product quality, cleanliness, and compliance with regulatory standards. Whether in-process, stability, or environmental sampling, consistency in the method ensures reliability and comparability of data. Modifying the sampling procedure during an ongoing study—such as changing sample size, location, technique, or frequency—can invalidate the study’s conclusions and compromise data integrity. GMP emphasizes that sampling plans must be pre-approved, validated, and strictly adhered to unless changes are formally approved through a change control or deviation process.

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Unjustified procedural changes introduce variability, create documentation gaps, and raise concerns during audits or product reviews. They also affect trending data, comparability of batches, and quality risk assessments, making regulatory defense difficult in case of complaints or recalls.

Regulatory and Compliance Implications

FDA 21 CFR Part 211.160(b) requires scientifically sound sampling procedures documented and followed. EU GMP Chapter 6 stresses consistent sampling with defined acceptance criteria and methods. WHO GMP and Schedule M require that any change in

analytical or sampling methods must be pre-approved by QA and documented. Inspectors review sampling plans, study protocols, and change control logs. Any unapproved deviation from procedures is treated as a compliance lapse, often categorized under data integrity violations or poor documentation control.

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Implementation Best Practices

Ensure all sampling procedures are pre-defined, validated, and documented in study protocols and SOPs.
Route any procedural modification through formal change control or deviation processes, with QA review and approval.
Maintain detailed records of sampling events, including who performed the sampling, where, when, and how.
Train staff to report challenges in sampling without altering the procedure independently.
Verify the sampling consistency during study reviews, trending, and final report compilation.

Regulatory References

FDA 21 CFR Part 211.160 – Laboratory Controls and Sampling Procedures
EU GMP Chapter 6 – Quality Control and Sampling Consistency
WHO GMP – Sampling Plan Documentation and Control
Schedule M – Study Protocol Compliance and Sampling Controls

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