Cervical Cytology Practice Guideline
Approved by the ASC Executive Board November 10, 2000
V. Cervical Cytology Analysis
V.A. Individual Qualifications
Individuals qualified according to the Clinical Laboratory Improvement Amendments of 1988 (CLIA ‘88) must perform analysis of cervical cytology specimens.67 In most laboratories, screening is performed by cytotechnologists. Adequate support personnel should be available to minimize clerical duties for cytotechnologists. The laboratory must have a qualified pathologist serving as laboratory director or technical supervisor, and a general supervisor as defined by CLIA 88.68
Additional training is required to screen liquid-based cytology specimens and to perform computer-aided slide examination.
V.B. Environment and Equipment
Examination of cervical cytology slides should be performed in a comfortable area of the laboratory with minimal distractions. Ergonomics play a vital role in the cytotechnologist’s workstation to minimize the risk of repetitive motion injury and musculoskeletal strain. Adequate space, facilities and equipment must be made available to the cytotechnologist to perform his or her duties. Regular monitoring and maintenance of all equipment and instruments is essential. Proper equipment and resources include: sufficient desk or bench space, a cushioned chair with seat and height adjustment as well as adjustable back support, and a microscope in good working order. Arm rests that fit the desktop, tilting microscope heads, rubber focus knob adapters and devices that adjust microscope height are available options that increase the comfort of the technologist. Other factors include diffuse, moderate room illumination, a non-reflective desk surface, and a comfortable, draft-free room separate from the processing area58, 61 where protective equipment is required. Clerical and record-keeping areas of the laboratory should be located near the screening area.66
V.C. Analysis Time
The actual amount of time spent analyzing a given slide is highly variable. Factors influencing the amount of time spent examining a cervical cytology slide include method of sample preparation (liquid based vs. conventional), overall sample cellularity, blood, inflammation or other obscuring factors, clinical history, complexity of findings and the cytologist’s experience and state of mind. Workload limits must be set for each individual based upon an evaluation of the individual cytologist’s capability and, where applicable, feedback provided by the cytologist in the evaluation process, and must not exceed the limits set by CLIA ‘88.69 Individual workload limits apply to slides screened per hour and in any given 24-hour period. Screening rates must be monitored to ensure compliance with the workload limits established for each individual.
V.D. Screening Process
Screening processes vary among cytologists based upon experience level, personal preference and other factors. However, certain procedures should be followed. The process of screening should always begin with a check of slide identification (name and/or identifying number) against the accompanying accession slip, test request or pertinent lab document. The examiner must consider available patient history provided by the ordering clinician.
The screening process usually begins with a low power scan of the specimen to assess background and overall adequacy. The actual screening process is usually performed with a 10X objective and 10X or 15X eyepieces. Higher magnification is used for more detailed observation of potentially abnormal areas. The slide should be screened in a systematic and thorough process.
The individual screening the slide is responsible for assessment of adequacy in addition to locating and identifying reportable findings. These findings include premalignant or malignant cells, reactive or reparative features, microorganisms and any features that are not consistent with the clinical history. The location of any abnormal cells or reportable findings should be marked in a consistent pattern by all cytotechnologists within the laboratory to facilitate review. When marking slides, care should be taken to avoid obscuring other significant cellular material.
V.E. Recording results and hierarchical review
After examining and marking the slide, the cytotechnologist records his or her findings. All findings must be recorded accurately, legibly and precisely for future reviewers and data entry personnel. Cytotechnologists should be able to discuss the basis of their interpretations as well as demonstrate them at the microscope. All slides demonstrating reactive or reparative cellular changes and those with epithelial cell abnormalities must be referred to a qualified pathologist for final interpretation.
V.F. Variability in Practice
There are variations in cervical cytology analysis. To some extent, these variations are due to patient and client preferences, disease prevalence, laboratory resources, and market penetration of new technologies. Variability also includes differences in laboratory staff training and experiences,70 application of microscopic criteria, cytologist/support staff organization and availability of state-of-the-art laboratory information systems. Laboratories may use automated screening devices, liquid-based technology and/or conventional preparations. Hierarchical review may include rescreening by a supervisory level cytotechnologist before examination by a pathologist, or primary screening by pathologists and final sign out without a cytotechnologist. Variations in the methods employed to assess competency of newly hired cytotechnologists also exist.
There is also variability in the mechanics of slide screening. There are personal and laboratory preferences for the utensils used to mark reportable findings on a slide. These include manual dotting using a felt-tip pen or liquid ink on a sharp-tipped applicator, utilizing a manual device that attaches as a microscope objective to place an ink ring around cells of interest, utilizing a device that attaches to the 10X objective and is triggered electronically to place an ink dot next to the cells of interest and utilizing a device that electronically records the coordinates of areas of interest noted by the cytotechnologist, for subsequent hierarchical review.
For many of these variations of practice, the cytology literature contains little or no data gathered in comprehensive studies to permit conclusive recommendations regarding any one best practice. The College of American Pathologists has collected ASCUS/SIL ratios and other data from laboratories using its Interlaboratory Pap Comparison Program and the Q-Probes questionnaire, enabling individual laboratories to benchmark themselves against distributions of
performance.71, 72, 73 Many articles or textbook chapters present statements of opinion or descriptions of purported optimal practice. However, these practices may not be based on statistically significant data. There have been a number of individual reports that describe particular testing environments in detail,74 and one has displayed screening speed and accuracy data in a large laboratory setting.75 The College of Medical Laboratory Technologists of Ontario has recently completed a document, “Practice Guideline: Workload Guideline for Cytotechnologists,” which will have regulatory authority in Ontario, Canada.76 However, comprehensive and definitive laboratory trials assessing differing slide review speeds, hierarchical review algorithms and patterns of task execution as possible influences on result accuracy have not yet been performed.
71 Davey DD, Woodhouse S, Styer P, Stastny J, Mody D. Atypical epithelial cells and specimen adequacy: Current Laboratory practices of participants in the College of American Pathologists Interlaboratory Comparison Program in cervicovaginal cytology. Arch Pathol Lab Med 2000; 124:203-211.