CLINICAL LAB SCIENEC

CHAPTER 13: HEMATOLOGY AND COAGULATION 341
A
B
FIGURE 13-8 (A) Microhematocrit centrifuge with two sizes of centrifuge heads. (B) Crit-Spin centrifuge with
microhematocrit reader and capillary tubes with sealant.
Source: Delmar/Cengage Learning.
Anemia is defined as an Hct level lower than “normal” values. Anemia
may have a number of causes, including genetic abnormalities, inadequate
nutrition, blood loss, hemolytic disease (destruction of RBCs), and exposure
to substances such as radiation, certain pesticides, medications, or chemotherapeutic
agents that might affect the division of immature RBCs.
Initial and Weekly Quality Control
Microhematocrit centrifuges must periodically be tested for the “maximum
packed cell volume,” a process that is performed on a monthly basis (or
other regular schedule established by the facility’s policies) to determine if
electrical components of the centrifuge are deteriorating.
To determine the amount of time necessary for obtaining accurate
results, a series of measurements are conducted, where paired samples are
centrifuged for various lengths of time, (i.e., for 1.0 minute, 1.5 minutes, 2.0
minutes, and so on). When the result reaches a plateau and does not change
after the time of centrifugation is increased for another 30 seconds, the first
time in which the desired result was achieved is determined as the minimum
amount of time in which the Hct should be spun (centrifuged) to achieve
complete compaction of the RBCs. Usually a label is placed on the centrifuge
indicating the minimum length of time a specimen should be centrifuged.
Capillary tube
Plasma
Buffy coat
Red blood cells
Self-sealing plug
FIGURE 13-9 Column of blood
that has been separated by
centrifugation.
Source: Delmar/Cengage
Learning.
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