Instructions on how to use the Pipette Checkit in PDF format.
Calibration vs. verification
The Pipette Checkit® is a tool to identify potential volume delivery errors for pipettes. It is not a calibration tool. If your institution requires pipette calibration on a specific schedule, you should adhere to this schedule and use the Checkit
as an extra verification step between scheduled calibrations.
Expected performance at different volumes
Piston pipettes are most accurate at or near their nominal volume (the maximum volume the pipette can deliver). When a pipette is used near the bottom of its range, the measured volumes will vary more, and are also more strongly affected by slight variations
in pipetting style or environmental factors like humidity. The markings on the Checkit reflect this variation.
A note on environment: One advantage of the Checkit is that it can be used in the same room in which the experiment will be conducted. This can help identify variation in delivered volume due to pressure, humidity, or temperature differences
between the calibration environment and the experimental environment. Because the Checkit directly measures delivered volume rather than relying on gravimetric analysis, there is also no need to use correction calculations that account for these factors.
Accuracy and precision
Most pipette manufacturers provide specifications for both the accuracy and precision of their pipettes. Briefly, accuracy describes how close the mean of delivered volumes is to the stated volume, and precision describes the distribution of the volumes
around the mean. If you choose to compare your Checkit readings to the manufacturer’s specifications, remember to account for both accuracy and precision when determining what range is acceptable.
Note that ISO 8655 standards differ from the manufacturer’s standards. If your pipette has been recalibrated since purchase, you should check with your calibration service to determine which standards were used, and consider comparing your Checkit readings
to that standard rather than to the manufacturer’s standard.