What action is typically taken when a drift is detected during instrument performance verification?

• A. Calibrate only when the instrument fails.
• B. Ignore drift.
• C. Use a software filter to remove drift.
• D. Periodically verify instrument response against a stable standard to detect drift and perform recalibration if necessary.

Answer: (D)

When instrument performance verification detects drift, the important step is to regularly check the instrument against a stable reference and recalibrate if the readings deviate beyond allowable limits. Drift means the instrument’s response is gradually shifting over time, so you verify accuracy by comparing to a known, stable standard and not by assuming the current readings are correct. If the comparison shows a mismatch outside acceptable criteria, recalibration restores accuracy and keeps records of the adjustment for traceability.

Calibrating only when the instrument fails isn’t sufficient because drift can bias results before a total failure occurs. Ignoring drift endangers data quality and safety. Using a software filter to remove drift might mask the underlying bias and give a false sense of accuracy; it doesn’t correct the instrument’s true response or preserve proper calibration and traceability.