In a quality control program, how often should calibration procedures be performed?

• A. Daily calibration
• B. Yearly
• C. Once every 6 months
• D. Only when instrument fails

Answer: (C)

Regular calibration at defined intervals keeps measurements accurate by catching drift and maintaining traceability to standards. Instruments tend to drift slowly over time, wear, environmental changes, and component aging can all affect accuracy, so missing calibrations can lead to unreliable results. Calibrating every six months provides a practical balance: it is frequent enough to detect and correct drift before it impacts data, but not so frequent that it disrupts workflow. Calibrating daily is typically unnecessary for most equipment, and waiting a full year risks drift going unnoticed. Calibrating only after a failure is reactive and may allow incorrect data to influence results before the issue is addressed. Always align with manufacturer guidance and the lab’s quality system, but a six-month interval is the standard approach in many QC programs.