Nongynecological Cytology Practice Guidlines
prepared by the American Society of Cytopathology, Cytopathology Practice Committee.
Adopted by the ASC Executive Board, March 2, 2004
Quality control (QC) and quality assurance (QA) can be considered as the first two levels, respectively, in the hierarchical stages of quality.62 Quality control is defined as a system for verifying and maintaining a desired level of quality using operational techniques for an individual test or process. Quality control activities span the testing process, from pre-analytic (specimen collection and processing) through analytic (interpretive) and post-analytic (receipt of the report and analysis of results) phases. Quality assurance (QA) is defined by the College of American Pathologists as systematic monitoring of quality control results and quality practice parameters to assure that all systems are functioning in a manner appropriate to excellence in health care delivery.63 Quality assurance is a coordinated system designed to detect, control and prevent the occurrence of errors and, ultimately, to further a clinician’s ability to appropriately care for his or her patient. The third stage, quality system, consists of the comprehensive and coordinated efforts to meet quality objectives including the organizational structure and resources. Quality management, the fourth stage includes the first three and also the cost of quality. The hierarchy culminates with total quality management, which is management centered on quality, and aimed at long-term success through customer (patient, physician and payer) satisfaction.
A number of quality control and quality assurance measures for cytopathology have been specified by the Clinical Laboratory Improvement Amendments of 1988.64 All QC and QA processes must be described and documented in the laboratory.
VI.A. Pre-analytical Quality Control
Each laboratory must perform and maintain records of routine quality control relating to specimen collection, receipt and preparation. Most of these activities are required by lab accreditation agencies and include such things as:
Preparation and distribution of clinical specimen collection and handling instructions,
Assurance of properly labeled specimens,
Use of a requisition that provides space for all pertinent demographic and clinical data,
Accessioning and assignment of a unique specimen identifier,
Criteria for specimen rejection,
Review of stain quality and maintenance of stain quality records,
Procedure for preventing nongynecological specimen cross contamination,
Microscope and instrument maintenance,
VI.B. Analytical Quality Control
VI.B.1 Screening of Nongynecological Cytology Specimens
Federal regulations require that the individual examining a cytology specimen be a qualified cytotechnologist or pathologist in a certified laboratory.67 These individuals may examine up to 100 slides (gynecological and nongynecological) per 24 hours (average 12.5 slides/ hour) and in not less than eight hours. This number is not a performance target but a maximum allowed by law. Pathologists are limited by this ceiling when they perform primary screening. This includes nongynecological slides that have not been previously screened.68 Each laboratory must establish individual workload limits for each cytotechnologist.69 The Technical Supervisor of the laboratory must review these limits every six months and re-assess using lab defined performance standards. The record of slides reviewed by the primary screening cytotechnologist or pathologist must be documented and retrievable for inspectors during the retention period prescribed by CLIA ’88 or applicable state law. Cytotechnologists and pathologists must also maintain work logs for any primary screening site (in cases of multiple site employment), again, for the applicable retention period. As discussed in section VI, all specimens must be reported using descriptive nomenclature; use of a numerical reporting system alone is unacceptable.70
VI.B.2 Review and Reporting of Nongynecological Cases
All nongynecological specimens must be referred to a pathologist for final interpretation and final report.71 Discordance between pathologist and cytotechnologist interpretation, if the cases are screened prior to pathologist examination, can be used as a basis for identifying areas for continuing education. Peer review is often included in a quality assurance program. Multiple people may review difficult or interesting cases for educational and interpretive purposes. Laboratories may require a second pathologist opinion for specific diagnoses and/or type of specimen. See Section VI for variability of documenting intralaboratory consultations. Seeking the opinion of an outside consultant may be considered for unusually difficult cases with significant clinical implications. Documentation of all reviews is essential for quality assurance monitoring.
VI.B.3 Rescreening of Negative Cases
Quality control rescreening of nongynecological cases is not required by CLIA or accreditation agencies. However, re-examination of a subset of cases by a second pathologist prior to release of the final report may be incorporated into the anatomic pathology quality assurance program. The re-examined cases may be randomly chosen or may be selected based on volume and complexity of workload and cytopathology resources.
VI.C. Post-analytical Quality Control
VI.C.1. Cytological-Histological Correlation and Clinical Follow Up
The laboratory must make an effort to correlate nongynecological cytopathology findings with histology and clinical findings.6 This can be for all specimens or for a focused subset of specimens. It is suggested that if significant disparities exist they should be reconciled. Cytological-histological correlation can be an educational tool used to refine methods of evaluation for both cytology and tissue specimens. The correlation process should be documented in the laboratory quality assurance program. If a nongynecological cytology specimen is collected concurrently with a tissue specimen, cytological-histological correlation is best performed prospectively. Ideally, the cytology and tissue reports should each refer to the other with integration of the correlation statement into either report. Reporting cytological-histological discordance may be helpful in directing further patient management. If an abnormal or nondiagnostic nongynecological cytology result is subsequently followed with tissue sampling, and retrospective correlation is performed, then the result of the correlation should be documented. If histological material is not available, the laboratory may attempt to obtain patient follow-up by sending a letter to the ordering physician requesting this information.
VI.C.2 Retrospective Reviews
There are no federal or accrediting agency requirements for retrospective review of nongynecological cytology specimens. In certain clinical situations, review of previously examined specimens may affect current patient care by determining subsequent management protocols. Retrospective comparison of specimens from multiple body sites within a relatively short time span may be required for clinical staging, or comparison of a current specimen with one from the remote past may distinguish a metastasis from a second primary neoplasm. Amended reports are not indicated in these situations. Results of the review can be incorporated in the current cytology or tissue report or in a separate document. Retrospective reviews are subject to the biasing effect of knowledge of outcome, and this fact should be kept in mind during any such review.
VI.C.3 Measures of Performance
Nongynecological cytology can be both a screening test and a diagnostic procedure depending upon the clinical circumstances and specimen examined. Nongynecological cytology is limited (as are all laboratory tests) by both false positive (FP) and false negative (FN) results. As a screening test, a false positive is defined as a “positive” test result for a patient who does not have an abnormality. As a diagnostic procedure, a false positive could be defined as a malignant interpretation when in fact the patient has a benign neoplasm or perhaps as the presence of any neoplasm when the condition is reactive or inflammatory. Since “positive” results are variably defined in the medical literature, a standard definition for a false positive nongynecological cytology specimen does not exist.
A false negative is defined in this document as a negative or nondiagnostic nongynecological cytology result in a patient with an abnormality or lesion. False negative results may be a consequence of (a.) Sampling variance, (b.) Laboratory interpretation, or (c.) General limitations of the method. Sampling false-negatives occur when diagnostic cellular and noncellular material is not collected or is not transferred to the slide. A laboratory interpretive false negative is one in which diagnostic material is present on the slide, but is not identified during slide examination or is misinterpreted as to its significance.
The false negative rate is the sum of lesions missed in sampling plus the false negative proportion (FNP.) The FNP is the measure of the laboratory component of false negative results and is defined as the number of false negative reports divided by the total number of patients sampled who have an abnormality (False Negative Proportion = False Negative reports/True Positive reports + False Negative reports).72,73,74
FNP = FN/TP + FN
The value of determining the FNP for a laboratory is widely acknowledged; however, precise calculation of the FNP requires 100% accurate determination of the true diagnosis. For nongynecological cytology this requires exhaustive cyto-histologic and clinical correlation, which is impractical.
The College of American Pathologists Q-Probes studies provide a comprehensive resource for comparative laboratory data and performance benchmarks. These data are a good starting point for laboratory self-assessment since operational definitions, laboratory methods and statistical analyses are specified.66
VI.D. Proficiency Testing and Continuing Medical Education
Proficiency testing for nongynecological cytology is not mandated under CLIA ‘88 as it is for individuals who examine gynecologic specimens. However, a number of private institutions provide educational programs for self-assessment and performance improvement activities. Examples include:
CAP Interlaboratory Comparison Program in Non-Gynecologic Cytopathology; www.cap.org .
CytoQuest ® Glass Slide Program from Midwest Institute for Medical Education (MIME); www.cytoquest.com .
CheckSample ®, CheckPath ® and STAR® Programs from the American Society of Clinical Pathologists; www.ascp.org.
These programs are not designed as proficiency tests nor should they be used as such.75
Ongoing education is a requirement for quality performance. This requirement can be fulfilled by participation in programs such as those listed above, intradepartmental slide review sessions, attending workshops and symposia, teaching cytotechnology students, pathology residents and fellows, independent study, and community outreach programs. Some states and professional societies have requirements for continuing medical education to maintain professional licensure.
73 Krieger PA, Naryshkin S. Random rescreening of cytologic smears: A practical and effective component of quality assurance programs in both large and small cytology laboratories. Acta Cytol 1994; 38:291-8.