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PRINCIPLE OF THE TEST.
Centrifugation can be done for any of three purposes: to make cell spreads;
to separate cells from their debris laden solution; or to form
a cell concentrate for surgical pathology embedding.
SPECIMEN REQUIRED.
Gynecologic cytology and non-gynecologic cytology specimens,
with a filled-out Tissue Examination Form (SF-515)
for non-gynecologic cytology specimens,
and Gynecologic Cytology Form (SF-541) for gynecologic cytology specimens.
REAGENTS, INSTRUMENTATION.
Cyto-Lyte Vial with specimen. Centrifuge.
STEP-BY-STEP DESCRIPTION.
1. CENTRIFUGATION can be done for any of the three purposes:
1. To obtain a cell concentrate (pellet),
from which to make cell spreads.
2. To separate cells from their debris-laden solution,
prior to filtration.
3. To form a cell concentrate, or "button",
for surgical pathology paraffin embedding methods.
2. EFFECT OF CENTRIFUGATION ON CELLS:
Although of little observable significance in exfoliative
cytology, several effects of centrifugation on the quality and
quantity of cells have been described. Reduction in numbers of
cells always occurs. It may be caused by one of the following factors:
1. Rupture of delicate, senescent, or degenerate cells
by shear stresses.
2. Impaction along the wall of the centrifuge tube,
or "walled effect".
3. Inadequate centrifugal force,
thereby causing some cells to suspend in the supernate.
4. Damage to the cellular morphology by centrifugal force is seen
primarily in the cytoplasm of the cells. Cells thus damaged can
exhibit ragged cytoplasmic borders. In turn, these borders can
cause cells to clump secondarily. The presence of protein in
some specimens largely protects against these effects.