CLINICAL LAB SCIENEC

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ESSENTIALS OF CLINICAL LABORATORY SCIENCE
1. Heat can be transferred to the instrument and its metallic components inside
the instrument. This can occur through such innocuous sources as heat from
the operator’s hand in contact with the handle of an instrument and transferred
to the metallic components in the instrument. Continuous operation
of a pipette for long periods of time may also result in significant heat
buildup inside the instrument, causing expansion of sensitive parts involved
in calibration. Increases in heat may reduce the accuracy, consistency, and
reproduction of data by the instrument. Since the volume that is delivered
depends in part on the piston sizes and the tension of the springs that provide
the movement for the piston, an action that provides negative pressure
results in aspiration of a fluid. Changes in the size of each of the components
will change the volume dispensed, and even minimal changes result in inaccuracies
for such a sensitive procedure. This effect is more pronounced in
low-volume instruments. Additionally, the expansion of a metallic component
that interacts with a nonmetallic one that does not expand as readily
in the presence of heat may cause the instrument to seem to stick, hang up,
or react more slowly. Pipettes with thin handles are particularly susceptible
to this phenomenon. Plumper handles are both more ergonomic and less
likely to suffer from heat transfer problems. The best technique for maximum
accuracy is to use multiple pipettes and rotate them often, storing them
between uses in a stand that holds them vertically.
2. Operator fatigue is an often-overlooked but crucial component when seeking
maximal accuracy and repeatability. Human beings are not robots, and
repetitive motions cause stress in human joints and muscles. Even a welltrained
and experienced operator will see a decrease in accuracy and replicability
as length of time on a workshift increases. It is for this reason that
pipette calibration service providers that are dedicated to excellence limit
the number of pipettes that can be calibrated by an individual technician to
a daily maximum. Each pipette, and each customer, deserves a high level of
care in the treatment of the instrument. Additionally, some dedicated professionals
train themselves to pipette ambidextrously, allowing them to reduce
arm and finger strain by alternating hands. Another solution is choosing an
electronic pipetter, which significantly reduces hand fatigue. Once the operating
button is touched, the pipetter always operates the same way, producing
user-independent accuracy and precision.
3. Long-term pipette operation can lead to repetitive strain injuries (RSI), such
as carpal tunnel syndrome. These injuries may cause significant reductions
in accuracy and repeatability by altering the proper pipetting techniques that
are crucial to achieving optimal accuracy. Preventive measures include learning
to pipette with both hands and alternating hand usage, taking frequent
breaks while pipetting, and choosing the most ergonomic (ease and safety of
handling) pipette available. Instruments with plumper handles are generally
superior in this regard. On the other hand, electronic pipetters, which operate
with a light touch, reduce RSI significantly.
4. Let the pipette “rest” for at least one minute after a volume change is made.
This does not apply to single-volume instruments, also called set volume or
fixed volume pipettes. A change in the dispensed volume of an adjustable
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