CLINICAL LAB SCIENEC

CHAPTER 7: MEDICAL ECONOMICS AND LABORATORY EQUIPMENT 175
A significant number of pieces of equipment
are essential to the smooth and effective
operation of medical laboratories. In the
following description of equipment and their
uses, most of these will be found in small to
large laboratories. Equipment is needed to
procure, prepare, and store samples. Equipment
is needed for storage and organization
of reagents and other supplies essential for
procuring, accepting, and processing patient
samples. A great deal of thought and study
should be undertaken to make the best decisions
related to factors such as manual versus
automated procedures, sensitivity and
specificity of equipment and test materials, as
well as other issues related to the needs of the
medical facility.
Centrifuges
A number of types of centrifuges are specialized
in their uses. They are all used to spin
biological samples to separate components
within the specimen. Centrifugal forces cause
the heavier materials to go to the bottom of the
tubes. Samples are centrifuged at speeds that
vary by procedure and type of sample. Most
commonly, blood is separated for tests where
the liquid portion (serum or plasma) is to be
used in the procedure. Specimens that require
blood cells would not normally require centrifugation.
The basic parts of the centrifuge,
regardless of type, are similar. The rotor is the
part that is spun by the motor of the centrifuge,
and is controlled by a timer and a speed
control.
Centrifuges are differentiated by the jobs
for which they were developed. Common centrifuges
used for separating blood into solid
and liquid components whether as plasma
(derived from anticoagulated specimens) or
serum (obtained from clotted samples) are the
most numerous types found in the laboratory,
and most laboratories have at least several
of each for basic types [Figures 7-3 through
7-7]). A microcentrifuge, or microfuge, is one
that is used to spin small tubes at high speeds
FIGURE 7-3 Microcentrifuge for small types of specimen containers.
Source: Delmar/Cengage Learning.
FIGURE 7-4 Test tubes that may be used in centrifugation.
Source: Delmar/Cengage Learning.
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