Pipetting Performance across Laboratory Personnel: A Comparative Study

Accurate and precise pipetting is critical for reliable laboratory results, especially when handling small volumes or sensitive analytical techniques. Despite the common use of piston-operated pipettes, operator-dependent variability remains a major source of error. This study aimed to evaluate pipetting performance among laboratory personnel with varying levels of experience.

The study included 108 participants: 26 laboratory school students (first to third year), 10 PhD students, 10 clinical chemists, and 62 laboratory technicians. Technicians were stratified into 3 groups based on the extent of sensitive manual pipetting in their work: minimal (Group A), moderate (Group B), and high (Group C). Pipetting performance was evaluated using gravimetric replicates at 10 µL and 100 µL volumes, and a dilution task involving serial dilutions of 1 M copper sulfate. Accuracy and precision metrics were compared across groups.

The median coefficient of variation (CV%) was lower for 100 µL replicates (0.3% to 0.8%) than for 10 µL replicates (1.4% to 5.9%). Laboratory students showed the greatest variability and longest task completion times, although performance improved with advancing school year. Ten percent of participants exceeded ISO-defined accuracy limits for 10 µL pipetting, and 22% for 100 µL. Imprecision limits were surpassed by 36% and 20% of participants for 10 µL and 100 µL, respectively. Group C technicians achieved optimal dilution performance (R2 = 1.00), while students showed the highest deviation.

Pipetting performance was significantly influenced by experience level and task sensitivity. Even experienced personnel occasionally failed to meet ISO standards, underscoring the need for ongoing training and performance assessment.