General Cytology
cytocentrifugation and ThinPrep techniques for cost efficiency
including wages, investments in instrumentation and con-
sumables, overall cytomorphologic quality, and suitability for
molecular studies.56 Based on their examination of 224 split
urine samples the authors reported that cytocentrifugation
with disposable chambers resulted in a global cytomorpho-
logic quality superior to that of ThinPrep. In addition utilizing
a 200-specimen per month calculation a greater cost efficiency
was achieved with cytocentrifugation than with ThinPrep. In a
similar subsequent study the same authors compared cytomor-
phologic quality of urine specimens prepared by ThinPrep,
direct smears, Cytocentrifugation, and ThinPrep and Millipore
The conclusions of the study were as follows:
• Direct smears show good overall results;
• Cytocentrifugation with reusable chambers should be
• Cytocentrifugation with disposable chambers (Cyto-
funnels or Megafunnel chambers) gives excellent
results; and
• Millipore filtration followed by blotting should be
avoided due to its poor global quality.
Contrasting results were reported when voided urine speci-
mens processed via Millipore filter cytosieve technique were
examined.58 True tissue fragments consisting of either flat
sheets or three-dimensional structures were significantly more
common in voided urine specimens with follow-up biopsies
of TCC than in negative biopsies. A considerably lower rate of
tissue fragments was reported when voided urine specimens
were processed utilizing cytocentrifugation with no statisti-
cally significant correlation found between the incidence of
cell groups in voided urine specimens and the presence of TCC
in follow-up biopsies.59 It has been suggested that the reason
for these discrepant findings is due to the stronger, more dis-
ruptive centripetal force imposed on true tissue fragments by
cytocentrifugation relative to the weaker, gentler forces of grav-
ity and suction encountered by the Millipore filter cytosieve
Specimen Cross-Contamination
The potentially catastrophic problem of cross contamination of
cytology specimens can occur with any processing modality or
in any stage of the process from fixation to coverslipping (Fig.
5.21). Fortunately steps can be taken in the specimen processing
and staining to minimize its rate occurrence in cytopreparatory
Specimen Processing
A. All test requisitions, specimen cups, tubes, and slides
must be identified with their own unique accession
number before processing.
B. Laboratory technicians must carefully aspirate sample
into pipette tip, making sure no sample gets sucked
into the pipette barrel. If this happens the pipette is
immediately removed from production. The barrel is
cleaned with alcohol and water, dried, and tested for
contamination before being placed back into produc-
C. Pipette tips are changed for every sample.
Fig. 5.21 Cross-contamination
from ovarian carcinoma (see Fig.5.15) in
pancreatic cyst FNA. Cell block (H&E x Mp).
D. All cytochambers and holders, if not disposable, are
soaked for at least 30 minutes and then washed in the
dishwasher and dried before being used the following
E. All staining solutions must be either filtered or
changed after every staining run.
F. All microscopists shall inform the supervisor of sus-
pected contamination. Immediate corrective action
shall follow with appropriate documentation of each
Specimen Staining
A. All stains and staining solutions must be checked,
filtered, and changed daily with documentation
supporting this. Discard all water rinses after
B. Special staining is to be performed in separate Coplin
jars with all reagents made fresh daily.
C. Hacker coverslipping xylene wells must be filtered
after each use.
D. Known positive cases should be stained separately in
Coplin jars or stained in the regular staining dishes
provided that the regular staining setup is then
discarded of all solutions.
E. Any suspected floater (atypical cell contaminant seen
on a different focal plane found on a slide) identified
on a slide should be brought to the attention of the
supervisor. For nongynecologic specimens, it is rec-
ommended that additional slides be made with the
leftover sediment. Again no staining should continue
until all stains, dishes, and jars are either filtered or
changed and cleaned.
F. If contamination is suspected and no residual speci-
men sediment is available, consideration must be
given to cancellation of the test. If the test is canceled
a phone call must be placed to the requesting clini-
cian and a hard copy of the report with appropriate
explanation shall be issued. All inquires will be docu-
mented in the reconciled report logbook.
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