Validation and Quality Assurance
Validation and Quality Assurance
This domain tests laboratory quality systems: method validation, proficiency testing, audits, and records. Quality assurance makes findings reproducible and defensible.
Core rules
- ISO/IEC 17025 accreditation covers testing and calibration competence. ASCLD/LAB and similar programs assess forensic labs.
- Maintain SOPs, training records, competency assessments, and equipment calibration. Control access to evidence storage.
- Validate methods for accuracy, precision, reproducibility, limits, and controls. Use reference materials and negative/blank controls where applicable.
- Participate in proficiency testing; investigate failures and document corrective actions. Internal audits and management reviews should drive improvement.
- Revalidate after significant software, hardware, or procedure changes. Maintain change control and version records.
Worked example
A new imaging tool version changes compression defaults. The lab images a reference drive with known content, compares hashes and extracted files against the prior version, documents differences, and updates the SOP. The validation record supports later testimony that the tool was fit for purpose in this configuration.
Traps
Assuming vendor validation covers the lab's method; missing training or competency records; not revalidating after updates; hiding proficiency failures; treating accreditation as a one-time achievement.
Key points
- ISO/IEC 17025 accreditation demonstrates competent quality systems.
- Method validation must precede casework.
- Proficiency testing and corrective actions are documented.
- Tool or procedure changes require revalidation.
- Quality records make findings reproducible and defensible.