NCJ Number
218721
Date Published
October 2003
Length
6 pages
Annotation
This article discusses possible sources of pipetting error in the forensic laboratory and presents suggestions for decreasing these sources of error through the use of straightforward quality control and operator training guidelines.
Abstract
Pipettes are defined as complex precision instruments that are at risk for error due to mechanical failure and improper operation. According to the authors, pipettes possibly contribute more inaccuracy and imprecision to laboratory results than any other single source. Strategies for reducing inaccuracies due to pipetting error include: (1) pipette technique training for laboratory personnel; (2) perform calibrations of the pipette in the laboratory using the same operators working under the same conditions in which the pipettes function; and (3) use 10 data points to verify the accuracy and precision of the instrument. Ten tips are also offered for improving pipetting technique: (1) pre-wet the pipette tip; (2) work at temperature equilibrium; (3) examine the pipette tip before dispensing; (4) use standard-mode pipetting; (5) pause after aspiration; (6) lift the pipette straight out; (7) minimize handling of the pipette and tip; (8) immerse the tip properly; (9) use the correct pipette tip; and (10) use consistent plunger pressure speed. Figures, references