Diagnostic Quality Assurance in Cytopathology


Introduction

Cytopathologists are concerned about and committed to quality assurance and quality control in their laboratories. These practices include, among others, the use of intralaboratory and extradepartmental consultations, case reviews, correlation of cytologic and histopathologic specimens, hierarchic review of cytopathology, and review of completed diagnostic reports. Most of the quality assurance techniques are well described.

In the past, formal organization and mandatory documentation of these quality assurance efforts may have been limited or deficient. Formal rules may be difficult to apply, because laboratories and screening programs vary, depending on the volume and type of cytodiagnostic material received and on the size and experience of its staff members. Even though the detailed design of a quality assurance program emanates from the cytopathology laboratory director, basic quality control and quality assurance principles of structure, organization, documentation, and systematic review must be in place.

The enactment of the Clinical Laboratory Improvement Amendment of 1988 by the US Department of Health and Human Services, the convening of two national conferences on cytologic quality assurance by the Centers for Disease Control, Atlanta, Georgia, the publication of the Quality Assurance Manual by the College of American Pathologists (1988), the American Medical Association Committee Report on the subject, the publication of the Compendium on Quality Assurance, Proficiency Testing and Workload Limitations in Clinical Cytology by the Tutorials of Cytology, and the proposal by the National Cancer Institute Workshop on the Bethesda System of reporting cytologic findings, as well as editorials, letters to the editors, and general public interest, led to the assurance of high diagnostic standards and fostered intense activities in the quality assurance and quality control sectors.

Quality Assurance Measures

Cytopathology is a practice of medicine and represents a medical consultation, in both gynecologic and non-gynecologic anatomic sites. The basic principles of quality assurance apply to all types of cytologic specimens.

The following represents several minimum quality assurance stipulations, to which most cytopathologists will probably agree.

Laboratory Directors

The laboratory should be directed by a legally qualified physician with a specialist qualification in pathology, including special training and expertise in cytopathology. In a case in which the current laboratory director or co-director (associate cytopathologist) does not have a board qualification in pathology but has had special training in cytopathology, this situation may be approved under a “grandfather clause.” The director or designated medical professional is responsible for proper performance and reporting of all tests done in the cytopathology laboratory. The director or designated cytopathologist should be physically present in the laboratory to direct the staff; be available for consultations; review all reactive and abnormal gynecologic cytology samples; review fine-needle aspiration samples; and review all non-gynecologic samples. In addition, a supervisor or senior cytotechnologist should be assigned to review 10% of the negative cases, including high-risk cases as designated by cytologic findings, clinical findings, and patient histories. This procedure should help to detect any discrepancies in interpretation that may occur prior to issuing the final cytologic report.

In addition, the director should develop a quality assurance plan, a manual of laboratory policies/procedures, and ensure the written policies and procedures reflect actual laboratory practice. Issues and problems identified through the quality management process need to be addressed and resolved. Gathering of laboratory statistics is best accomplished by collection of monthly reports during quality assurance meetings presided over by the director.

Cytotechnologists

Cytotechnologists should meet one of the following requirements:

  • 1.

    Be certified as a cytotechnologist by either the American Society of Clinical Pathologists or the US Department of Health, Education and Welfare; or

  • 2.

    Previously have been admitted to the practice of cytotechnology by existing regulations under a grandfather clause.

Physical Laboratory Facilities

The laboratory should be clean, well-lit, adequately ventilated, and functionally arranged so as to minimize problems in specimen handling, evaluation, and reporting. The area for specimen preparation and handling should be separate from the area where specimens are evaluated and reported. Formaldehyde and xylene (if in use) should be carefully monitored due to the possible presence of hazardous vapor concentrations.

Safety Precautions

Laboratory personnel must be protected against hazards (chemical, electric, fire, infections, or others) by using well-ventilated hoods and biologic safety hoods for handling potentially infectious material. Fire precautions should be posted and tested. Each employee should participate in fire drills and should know the location of the fire extinguisher, blankets, emergency fire alarm, and exits. Safety shower, eye wash stations, and procedures to follow in case of chemical spills or splash to the body should be posted and readily visible in the laboratory.

Equipment

An adequate number of binocular microscopes of good quality and in proper working order must be available. Laboratory instruments and equipment should be under periodic maintenance to monitor and ensure malfunctions do not adversely affect analytical results. A sample of slides from slide preparation instruments, including liquid-based technology and cytocentrifuge or filtration methods should be routinely reviewed microscopically for technical acceptability.

Specimen Collection

Cytologic specimens should be accepted and examined only if requested by a licensed medical practitioner and collected in accordance with instructions regarding recommended collection techniques. The cytopathology laboratory should inform the originator of the sample if the specimens are “unsatisfactory” and detail adequacy qualifiers, such as adequate numbers of squamous cells, presence or absence of a transformation zone component, or obscuring factors in “satisfactory samples”.

Preparation, Fixation, and Staining Procedures

The specimens must be identified with the patient's name and/or a unique identifier and must be accompanied by a requisition form with the requesting physician's name, address, date of specimen collection, specimen source, and appropriate clinical information about the patient. When the specimen arrives in the laboratory, the laboratory staff affix an accession number or barcode label on each slide for further identification. The laboratory should have written criteria for rejecting specimens. Fixation while the specimen is still wet is recommended for conventional cell samples, and rinsing of spatula and brush in preservative solution (kit provided by manufacturers) for liquid-based specimens. The Papanicolaou staining procedure is strongly suggested for most cytologic samples, unless additional staining procedures are warranted. Staining solutions and chemicals used in the cytopathology laboratory should be labeled with the time of preparation, purchase, or both. Staining solutions should be filtered regularly to avoid contamination and should be covered when not in use. Effective measures to prevent cross-contamination between gynecologic and non-gynecologic specimens during the staining process must be used. Separate runs followed by filtration or changing of solutions or a separate staining setup is recommended.

Slide Evaluation Workload

Regulations as to the number of specimens a cytotechnologist may evaluate in a 24-h period are currently set at 100 slides per an 8-h day. This regulation may not do justice to the various conditions that influence the quality of the slide evaluation performance. The percentage of atypical cases evaluated versus the percentage of negative cases in varying populations as well as screening of non-gynecologic specimens should be considered when workloads are established. This regulation ensures that the number and type of cytologic samples evaluated do not, through fatigue, adversely affect the cytotechnologist's performance. Some slides are easier and less fatiguing to evaluate and some cytotechnologists are more experienced than others. Other activities in which the cytotechnologist participates, such as participation on the fine-needle aspiration service and quality control activities, should appropriately reduce their workload in the evaluation of cell samples. The interpretation of the cytotechnologist should become a permanent record and available for future review.

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