A new study by COEH researchers indicates
that changes in pipette design and proper employee training may help to
reduce the high incidence of hand pain, tendon disorders and fatigue among
laboratory workers who use these devices.
Pipettes are among the most common tools
used in the biotech industry. Handheld devices with a button the thumb
operates to activate a plunger that draws up fluid, pipettes are the primary
way that laboratory technicians move small amounts of fluid from one container
to another.
“In every laboratory, when fluids are moved between containers,
the transfer is almost always done with a pipette,” said COEH faculty
member
David Rempel, who headed the study. “It’s the only
way to obtain a very precise quantity of fluid.”
Rempel, professor of medicine at UC San Francisco and professor of bioengineering
at UC Berkeley, directs COEH’s Ergonomics Program. He was assisted
in the pipette study by Krishna Asundi, doctoral student in the Joint
Bioengineering Graduate Program at UC San Francisco and UC Berkeley, and
former post-doctoral fellow Joel Bach, who is now assistant professor
of engineering at the Colorado School of Mines.
“If people use pipettes for long hours during the day, they can
experience pain in their thumb, wrist and shoulder,” Rempel said.
“We wanted to understand better what the thumb experiences when
people use the pipette—the forces involved and the muscle activity
the thumb has to apply. We found that the force used to press down on
the pipette is relatively high for someone to do six to eight hours a
day. There are ways a person can change the task and ways the pipette
can be modified to reduce that force. For example, pipetting tasks that
involve very high precision work increase the muscle activity of the hand.
So redesigning the task to use larger volumes or larger targets for the
fluid would reduce the requirement for very high precision.”
Rempel said the design of pipettes can be modified to reduce some of these
risk factors. For example, the spring in the plunger can be modified so
that it requires less force to press it down, and the plunger location
and buttons can be modified to fit the hand better.
He said manufacturers have a great incentive to make these changes, because
they want to provide the most comfortable and safest pipettes possible
for buyers. And buyers will pay attention, he predicted: “We are
beginning to see more workers’ compensation cases of people with
pipette-related hand problems. The cost of a workers’ compensation
claim is so high relative to the cost of a pipette that it makes sense
to pay more money for well designed pipettes.”
