ARTEL Study Shows that Pipetting Warm and Cold Liquids Causes Error of up to 37 Percent
News Jul 17, 2007
Data taken at Yellowstone National Park during Mission #2 of the ARTEL Extreme Pipetting Expedition show that pipettes deliver volumes inaccurate by up to 37 percent when handling fluids at temperatures different from the pipettes.
Called thermal disequilibrium, this source of error is prevalent in today’s laboratories, as many assays and tests require the addition of liquids which are warmer or colder than the laboratory environment and the actual pipettes.
Yellowstone was selected for Mission #2 of the Expedition because it is emblematic of thermal variation and disequilibrium. The Extreme Pipetting Expedition is a multi-phase, year-long scientific study to investigate and illustrate the impact of laboratory conditions on data integrity.
ARTEL is releasing the results from Mission #2 of the Extreme Pipetting Expedition at the 2007 AACC Annual Meeting & Clinical Lab Expo, San Diego, CA, July 17-19, Booth #4143. The data will also be published at www.artel-usa.com/extreme.
“From our testing at Yellowstone, it is clear that pipettes show a bias in volume delivery when dispensing fluids at different temperatures, and the error is especially significant when handling small liquid quantities,” says George Rodrigues, Ph.D., Senior Scientific Manager at ARTEL and Expedition Leader. “Laboratories must account for this variation to ensure good accuracy and precision in test results.”
Data taken at Yellowstone show that error caused by thermal disequilibrium was significant when using smaller volume pipettes at their minimum volumes. For example, a two-microliter variable-volume pipette set to deliver 0.2 microliters over-delivered cold liquid (3oC) by 37 percent and under-delivered warm liquid (45oC) by 24 percent, compared with liquid at room temperature (21oC). When set to deliver its maximum volume (two microliters), the pipette over-delivered cold liquid by one percent and under-delivered warm liquid by seven percent.
As expected, error was present, but smaller, when working with larger liquid volumes. The 20-microliter pipette set to deliver two microliters over-delivered cold liquid by four percent. When the pipette was set to deliver its maximum volume of 20 microliters, the overdelivery amounted to 0.6 percent.
“There are not many laboratory managers who would knowingly accept error of more than a few percent, let alone error of 37 percent,” says Doreen Rumery, Quality Control Manager at ARTEL and Extreme Pipetting Expedition member. “Yet many technicians frequently pipette warm and cold liquids in critical testing and assay work without accounting for volume variation.”
The aim of the Extreme Pipetting Expedition is to raise awareness about common laboratory extremes that can affect data quality, including the thermal disequilibrium phenomenon.
“Since the magnitude of error is dependent on a number of protocol-specific details, such as pipetting speed and type of sample container, a one-size-fits-all correction factor does not currently exist,” says Rodrigues. “ARTEL will continue to study thermal disequilibrium to help laboratories develop strategies to minimize this source of laboratory error.”
Volumes were measured using the ARTEL PCS® (Pipette Calibration System), a portable measurement technology based on ratiometric photometry.
Cell Chimeras Provide Muscular Dystrophy BreakthroughNews
Fusing together healthy cells with those affected by Duchenne Muscular Dystrophy could improve muscle function.READ MORE
New Chemical Synthesis Process: Synergy of Two Catalysts in One FlaskNews
Researchers report the one-step synthesis of a ketone from an aldehyde by the combination of thiazolium N-heterocyclic carbene and palladium/bisphosphine catalysts in one flask. The two catalysts function in a synergistic manner. This study is expected to lead to new synthesis processes of precursor compounds for medications.READ MORE
Comments | 0 ADD COMMENT
World Congress on Pathology and Laboratory Medicine
Sep 10 - Sep 11, 2018
World Congress on Advances in Addiction Science and Medicine
Sep 24 - Sep 25, 2018
International Conference on Molecular Biology and Stem Cells
Aug 13 - Aug 15, 2018
World Congress on Plant Science and Molecular Biology
Sep 12 - Sep 13, 2018