How is a calibrated instrument defined?

• A. A calibrated instrument has been adjusted and validated against known standards
• B. It has not been adjusted against any standard
• C. It has been adjusted but not validated
• D. It uses the most advanced software

Answer: (A)

Calibration means an instrument is adjusted so its readings align with measurements from known reference standards, and this alignment is validated to confirm accuracy. When an instrument has been adjusted and validated against known standards, it is considered calibrated because the adjustment brings the output into agreement with the standard and the validation proves it remains accurate across the expected range. This also provides traceability to recognized standards and documented performance.

If an instrument hasn’t been adjusted against any standard, its readings aren’t proven to be accurate. If it has been adjusted but not validated, you can’t confirm it meets the required accuracy across the operating range. Simply having advanced software doesn’t make something calibrated—the calibration claim rests on alignment with standard references and documented validation.