PART ONE
General Cytology
The ThinPrep Imaging System was statistically more sensitive
than manual evaluation for detection of ASCUS or more severe
lesions and statistically equivalent for LSIL and HSIL diagnoses.73
According to Biscotti et al.74 the sensitivity of this system equals
or exceeds the sensitivity of manual screening without adversely
affecting specificity. Significant increase in SIL detection was
demonstrated with the TIS by Dziura et al.75A recent study by
Bolger et al.76 showed sensitivity and specificity of the imager
equivalent to that of primary manual screening.
These devices may improve the rate of false-negative evalu-
ations—but at a price. In other words, in the quality control
mode the question is not whether the use of either instrument
may be harmful to the patient but whether the cost-benefit
ratio is such that supplemental funds will be made available
by third-party payers to support this additional quality control
procedure. Currently several third-party payers have reimbursed
for these procedures and current procedural terminology (CPT)
codes are available for billing purposes. For additional informa-
tion see Chapter 34.
Before automated devices can be effectively applied in pri-
mary screening, one will have to consider other major factors
that preclude successful reduction of prevalence and incidence of
gynecologic precancerous and malignant lesions. To obtain max-
imum results for a population-screening program, we need to
educate women to obtain periodic gynecologic examinations, to
teach medical personnel to take and fix the specimens appropri-
ately, to make sure laboratory personnel follow proper staining
procedures, and to ensure the patient will make herself readily
available for required repeat cytologic examinations, colpos-
copy, and/or biopsies. After a certain time of intensive cytologic
evaluation, prevalent cancers and high-grade precursors will have
disappeared (the "sweeping" effect of an effective population-
screening program). What remains are incident low-grade precur-
sors and "interval" cancers and "interval" high-grade precursors
that in fact are missed positives (i.e., false-negatives), if one does
not believe in the very rapidly growing malignant lesion.
We should also re-emphasize to cytotechnologists that their
services are urgently needed in the future, even with approval of
automated devices for routine application, because the systems
either work interactively under cytotechnologic and cytopatho-
logic guidance or produce alarm messages on selected cases that
in fact do not contain atypia (false-positives), which will take
extensive effort and time by a human re-evaluator to locate and
override the alarm message.
The development of a
fully
automated diagnostic cytology
and histology system, i.e., complete without professional inter-
action and involvement, was and remains a daydream that is
neither feasible nor desirable. However, interactive systems
as aids in quality assurance mechanisms and improvement
of productivity are
constructive developments
and major
technologic accomplishments.
External Quality Assurance Mechanisms
External quality assurance mechanisms with peer review by
professional organizations or by state or federal governmental
bodies are currently being implemented. The Center for Medi-
care and Medicaid Services (CMS) has approved two proficiency
tests by the American Society for Clinical Pathology (ASCP)
and College of American Pathologists (CAP). Some states,
e.g., New York and Maryland, have had a testing program for
cytopathology laboratories enacted and operational for many
years.42,77 Any external program will be welcomed by the high-
quality laboratory, but there may be problems in the funding
and execution of an unbiased, objective, and reproducible test-
ing system.19,34,38,39,44,46,47,51,78-80,82 Members of the Cytopathology
Educational and Technology Consortium have recommended
modifications of the rules regarding proficiency testing includ-
ing testing interval, utilizing validated and monitored slides,
and changing the grading system.81
Continuing Education Practices
The laboratory director should conduct continuing educational
activities within the laboratory; provide up-to-date reference
materials, such as cytopathology textbooks, compendia on
clinical cytology, cytologic journals, visual image teaching slide
sets, cytology websites, and CDs. The staff should be encour-
aged to participate in ongoing educational events, such as local,
regional, national, and international cytology meetings and
tutorials.
Concluding Remarks
The described quality assurance stipulations represent mini-
mum quality assurance measures to which most laboratories
adhere. In the United States laboratories are also governed by
the described standard requirements of CLIA 88. External test-
ing programs are a welcome component of a laboratory qual-
ity assurance but there may be problems in the execution of
an unbiased, objective, and reproducible evaluation system.
A number of professional organizations are working with the
federal government in the United States to improve the cur-
rent CLIA 88 cytology proficiency testing. Unacceptable errors
do occur in the cytology laboratory. Automated systems and
molecular HPV testing are available and may help to reduce the
false-negative rate of the Pap test. Continuing education prac-
tices and a creative learning environment for the cytotechnolo-
gist and cytopathologist are necessary to improve the diagnostic
results for the patient.
References
1.
Allen K: Quality control. In: Tirol JH (ed)
ASCT Cytopathology Quality Assurance
Guide,
vol I. Raleigh, NC: ASCT, 1992.
2.
Anderson GH, Flynn KJ, Hickey LA, et al.
A comprehensive internal quality control
system for a large cytology laboratory.
Acta Cytol
1997;31:895-910.
3.
Bonfiglio TA. Quality assurance in
cytopathology: Recommendations and
ongoing quality assurance activities of the
American Society of Clinical Pathologists.
Acta Cytol
1989;33:431-433.
4.
Erozan YS. Quality control in cytopathol-
ogy.
Clin Lab Med
1986;6:707-713.
5.
Gay JD, Donaldson LD, Goellner JR.
False-negative results in cervical
cytologic studies.
Acta Cytol
1985;29:
1043-1046.
6.
Hindman WM. A proposal for quality
control in gynecologic cytology.
Acta Cytol
1987;31:384-385.
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