How often should semi-automated micropipettors be calibrated?

• A. Every 3 months
• B. Every 6 months
• C. Every 12 months
• D. Every 18 months

Answer: (B)

Regular calibration is essential for maintaining accurate and reliable pipetting because semi-automated micropipettors can drift over time due to wear of seals, piston movement, and tip fit, as well as changes in ambient conditions and handling. This drift, even if small, can introduce systematic bias in measured volumes, which is critical in quantitative lab work.

Six-month intervals are commonly recommended for routine calibration of semi-automatic pipettes because they strike a balance between catching drift early and the practical workload of frequent checks. Many manufacturers and quality systems expect regular verification and calibration on a semi-annual basis, especially for devices used in routine or moderate-to-high throughput work. This interval helps ensure accuracy within specified tolerances and maintains traceability, which is important for compliance and reliable results.

If usage is extremely high, if the environment is variable, or if the pipettor has shown any deviations, calibration may be warranted sooner. Conversely, in low-use, stable conditions, some labs may extend beyond six months, but the standard teaching point is that six months is a typical, generally acceptable interval.