Which statement is true about micropipette accuracy?

• A. It is least accurate when measuring at the bottom of the range
• B. It is most accurate at the bottom of the range
• C. It has equal accuracy across the range
• D. Accuracy is not important for micropipettes

Answer: (A)

Accuracy in micropipetting varies across the volume range. The smallest volumes are the hardest to deliver precisely because the pipette’s fixed absolute errors (from calibration, the air cushion, tip fit, and the plunger mechanism) become a larger portion of the delivered amount. As a result, the relative error is larger at the bottom of the range, making accuracy lowest there. This is why the statement that it is least accurate at the bottom of the range best reflects how micropipettes behave in practice. The idea that accuracy is highest at the bottom, or the same across the range, or unimportant, doesn’t fit with how these tools and their tolerances work.