Calibration vs Verification in Laboratories

Calibration vs Verification in Laboratories: Calibration establishes a relationship between indications and reference quantity values, with associated uncertainty. Verification checks whether specified requirements have been met.

Why this topic matters: A calibrated instrument is not automatically fit for its intended laboratory task. Users must judge performance against actual method requirements.

Step 1 — Scope the problem: Identify what the measurement system is used for and the permitted error or tolerance for that use.

Step 2 — Apply the method: Arrange calibration with appropriate traceability and uncertainty, then review results and any adjustments or limitations.

Step 3 — Sustain the result: Perform fit-for-purpose verification at defined intervals and investigate work affected by out-of-tolerance findings.

Practical laboratory example: A pipette has a traceable calibration certificate, but its delivered volume at a critical assay setting exceeds the laboratory's allowed error. It may fail verification despite being calibrated.

Common errors: Treating a certificate as automatic acceptance, neglecting intermediate checks, or applying laboratory tolerances that lack a technical basis. Procedures need to withstand real laboratory conditions and staff turnover, rather than merely look complete during audits.

Evidence to keep: Calibration certificates, acceptance calculations, intermediate checks, maintenance, equipment status and impact assessments. The records should allow an independent reviewer to reconstruct how and why technical decisions were made.

Action to take this week: For one critical instrument, write the exact criteria that make it fit for use after calibration. Assign an owner and decide what evidence will demonstrate improvement.

Authoritative references: ISO/IEC 17025:2017 and method or equipment specifications. Always obtain the applicable standard and check its scope before interpreting this educational overview as an accreditation requirement.