The autopsy and clinical diagnosis.
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Age Factors↗
Biomedical subjects
E McGoogan
Publications and source records attributed to E McGoogan.
A prospective study of 1152 hospital autopsies: I. Inaccuracies in death certification.
Comparison of certified clinical diagnoses with autopsy findings showed that, while the major cause of death was confirmed in 61 per cent. of cases, many diagnoses--both major and contributory--were wrong; many clinical diagnoses were either disproved or relegated to a less important role, and many autopsy findings had not apparently been anticipated. Accuracy was particularly poor in some clinical categories: notably cerebrovascular disease and infections. In these, the diagnosis was more often wrong than right. Thus, death certificates are unreliable as a source of diagnostic data. The clinician's confidence in his major diagnosis bore a fairly close relationship to the frequency of its confirmation. Nevertheless, even when certified as "fairly certain", the major diagnosis was wrong in about one-quarter of these cases. An attempt was made to assess the significance of incorrect diagnoses; one half of these might be clinically significant. Diagnostic accuracy did not improve with the time spent in hospital, and it bore an inverse relationship to the patient's age.
Adolescent↗
A prospective study of 1152 hospital autopsies: II. Analysis of inaccuracies in clinical diagnoses and their significance.
A further analysis of 1152 hospital autopsies provides data on inaccuracies of specific diagnoses; there are many examples of overdiagnosis and underdiagnosis. All were encountered in a routine hospital autopsy service and their frequency confirms the importance of the hospital autopsy in medical audit. A knowledge of the misdiagnoses which recur frequently could provide guidance in the selection of cases for autopsy.
Abdomen, Acute↗
Necropsy: a yardstick for clinical diagnoses.
An attempt to obtain necropsies on all deaths from a selected group of clinical units resulted in a necropsy rate of 65% (compared with a normal of 30% in these units). The effect of increasing the necropsy rate was to produce a higher rate of confirmation of clinical diagnoses; nevertheless, 15% of main diagnoses and 42% of causes of death were not confirmed. A large proportion of these were deemed by clinicians in consultations with pathologists to be clinically significant. Of main diagnoses considered certain, 10% were not confirmed. The proportion of diagnostic discrepancies was virtually identical in two groups--those in which the clinicial believed he would normally have requested necropsy, and those in which he would not. Thus clinical confidence in the diagnosis is not an adequate assurance of its accuracy. Although in this survey necropsy was requested on almost all cases, permission was refused in many which may be attributed either to resistance by relatives or to an inadequate approach by the medical staff. The proportion of permissions secured by individual units varied from 50% to 92%. This indicates that the nature of the approach to relatives is the more important factor. As present practices do not adequately allow for the detection of a wide range of misdiagnoses and missed diagnoses it is proposed that a "partial audit" would provide a valuable yardstick; clinicians would be asked to obtain permission for necropsy on an agreed proportion (say, 20%) of deaths over and above those cases in which they are particularly interested and would normally request a necropsy.
Age Factors↗
Clinical attitudes to the autopsy.
An enquiry into the attitudes of clinical consultants to autopsies was conducted by questionnaire. Responses indicate that most of the consultants accept that the autopsy is important in hospital practice and in teaching. There are, however, marked differences of view on the reasons for doing autopsies, and on the results of autopsies (e.g. in altering diagnoses or revealing unsuspected pathology), differences which influence the freqeuncy with which autopsies are requested. Some clinicians believe that increasing resistance by relatives to granting permission contributes to the falling rates, but this is a minority view. Clinicians also vary in their reactions to the falling rate, some regarding it as worrying while others are not concerned.
Attitude of Health Personnel↗
Trends in hospital necropsy rates: Scotland 1961-74.
Examination of mortality statistic for Scottish hospitals showed that from 1961 to 1974 necropsy rates fell by almost 0-6% a year; by 1974, the rate over the whole country was 23% of hospital deaths. The fall resulted from a reduction in the number of necropsies and a coincident rise in the number of number of deaths in hospital. The necropsy rate fell with increasing age, was rather lower for women than men, and was lower for some diseases than others. There were considerable inaccuracies in the figures from which these trands were drawn, and these were in turn due to inaccurate recording of clinical and necropsy data. Examination of necropsy returns from the Scottish teaching hospital departments showed that, while a similar fall in necropsy rates was seen in some, there was no consistent pattern.
Adolescent↗
Autopsies and medical records.
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Autopsy↗
Competency assessment and proficiency testing.
Competency assessment is an ongoing, continuous process of monitoring individuals' abilities to perform their specific job functions. A variety of methods are useful in monitoring cytology competency, including rescreening studies, descriptive monitors (abnormality rates), discrepancy rates, workload patterns, competency-based educational programs and programs using unknown slide challenges. The goal of proficiency testing (PT) is to ascertain and assess the ability of individuals beyond the particular items or challenges presented. However, cytology PT faces many challenges for implementation as it cannot duplicate normal working conditions, and there is often no gold standard to define the truth. PT is just one measure of performance and should be considered in conjunction with other quality assessment monitors. There is no consensus on the value or validity of a large-scale regulatory PT program. Any regulatory PT program should be field tested prior to implementation, and the grading system should be scientifically defensible. Scoring of performance on PT should occur in a timely fashion, and there should be an opportunity for educational feedback. The ultimate aim of both competency assessment and PT is to positively affect laboratory procedures and improve the cervical cancer screening process.
Cell Biology↗
Cell preparation methods and criteria for sample adequacy. International Academy of Cytology Task Force summary. Diagnostic Cytology Towards the 21st Century: An International Expert Conference and Tutorial.
ISSUES: Cell Preparation Methods Standardized fixation and optimal staining Sampling of cervix, sampling error, homogenization of sample, subsampling Assessment of liquid-based preparations: efficacy and economic impact Training and transitional procedures before full implementation of new technologies Criteria for Sample Adequacy Clinician responsibility for collecting and providing representative sample to laboratory Collection instruments, number of slides Cellular content of samples: evidence of transformation zone (TZ) sampling, number of squamous cells present, obscuring factors Screening issues CONSENSUS POSITION The conventional cervical smear remains the standard method of cervical cancer screening but has limitations in individual test sensitivity and specificity. Sample takers should: (1) receive appropriate training in sample collection, (2) be held responsible for providing the laboratory with appropriate samples, and (3) have their performance monitored. The instruments used for sampling should collect cells from both the ectocervix and endocervix; optimally, TZ sampling, represented by the presence of endocervical or squamous metaplastic cells, should be identifiable in samples other than atrophic specimens. The adequacy of a specimen (as judged microscopically) does not guarantee that it is representative of the cervix. Each cytology report should include a comment on cellular content/adequacy of the specimen. Liquid-based preparations may overcome many of the inherent problems with the conventional cervical smear. ONGOING ISSUES: We need further data on the cost-effectiveness of making two slides from cervical specimens and/or using two samplers rather than a single one. Do we have enough information to make recommendations as to the appropriate type of sampler to be used in particular situations, such as routine screening? What is the best method of screening for/detecting endocervical glandular neoplasia? How are such terms as unsatisfactory and inadequate defined in cervical cytology classifications other than the Bethesda System? What number and types of epithelial cells should be present (visualized) in a cervical smear or liquid-based preparation for it to be considered adequate? Do we need to have evidence of TZ sampling in specimens taken during the follow-up period after treatment of squamous intraepithelial lesion or after detection of endocervical glandular neoplasia? What criteria for obscuring factors, such as blood and inflammation, should be used in assessing adequacy? Cost-benefit analyses of utilizing liquid-based preparations are needed. Should we inform women about the technical details of the test methods available or chosen by the laboratory? Are women in a position to decide which method is the most appropriate to assess their cervical scrape sample? We need to obtain more information about the properties of proprietary liquid fixative/transport media with respect to inactivation of viral pathogens, tuberculosis and other bacterial pathogens and suitability for immunobiologic and molecular tests, etc. We need to obtain more information on the use of stoichiometric stains and the limitations of Papanicolaou stain for image analysis systems. The use of liquid-based preparations for nongynecologic cytopathology and ancillary tests must be considered, including criteria for adequacy. We need to obtain more information on the time required for and best methods of training experienced cytotechnologists to become competent at assessing liquid-based cervical preparations.
Cell Biology↗
Quality assurance/control issues. International Academy of Cytology Task Force summary. Diagnostic Cytology Towards the 21st Century: An International Expert Conference and Tutorial.
ISSUES: General definitions of quality assurance and quality control (QA/C) have existed in many forms for decades, and a new discipline guides their application to diverse industrial and recently medical processes without much fanfare. However, in the field of cervical cytology screening, the range of QA/C options has recently broadened and become controversial. With the advent of new systems of terminology, larger-scale laboratories and new technologies--plus strong governmental and legal pressures in some nations--the range of extremely difficult and sometimes expensive QA/C choices our community faces is greater than ever. CONSENSUS POSITION: At our conference, the basic definitions of QA/C posed little difficulty. Presentation of the range of methods in use today and of those based on new technologies where use is proposed or has just begun also was achieved with little or no dispute. However, there was lack of consensus on exactly how QA/C methods are to be assessed. Indeed, there was little consistency in the use of different outcome measures with which we can judge success or failure of specific QA/C options. In addition, the tension between pressure to adopt sometimes uncertain or expensive method enhancements and pressure to maintain affordability and the widest possible access for populations that most need cervical cytology screening is greater than ever. ONGOING ISSUES: More data are required that would enable assessment of QA/C options with the clearest possible understanding of cost/benefits and current or new assumptions of risk. Other task forces, such as medicolegal, cost/benefit and those devoted to new technologies, are our essential partners in meeting the challenges described above.
Centers for Medicare and Medicaid Services, U.S.↗
Digital imagery/telecytology. International Academy of Cytology Task Force summary. Diagnostic Cytology Towards the 21st Century: An International Expert Conference and Tutorial.
ISSUES: Optical digital imaging and its related technologies have applications in cytopathology that encompass training and education, image analysis, diagnosis, report documentation and archiving, and telecommunications. Telecytology involves the use of telecommunications to transmit cytology images for the purposes of diagnosis, consultation or education. This working paper provides a mainly informational overview of optical digital imaging and summarizes current technologic resources and applications and some of the ethical and legal implications of the use of these new technologies in cytopathology. CONSENSUS POSITION: Computer hardware standards for optical digital imagery will continue to be driven mainly by commercial interests and nonmedical imperatives, but professional organizations can play a valuable role in developing recommendations or standards for digital image sampling, documentation, archiving, authenticity safeguards and teleconsultation protocols; in addressing patient confidentiality and ethical, legal and informed consent issues; and in providing support for quality assurance and standardization of digital image-based testing. There is some evidence that high levels of accuracy for telepathology diagnosis can be achieved using existing dynamic systems, which may also be applicable to telecytology consultation. Static systems for both telepathology and telecytology, which have the advantage of considerably lower cost, appear to have lower levels of accuracy. Laboratories that maintain digital image databases should adopt practices and protocols that ensure patient confidentiality. Individuals participating in telecommunication of digital images for diagnosis should be properly qualified, meet licensing requirements and use procedures that protect patient confidentiality. Such individuals should be cognizant of the limitations of the technology and employ quality assurance practices that ensure the validity and accuracy of each consultation. Even in an informal teleconsultation setting one should define the extent of participation and be mindful of potential malpractice liability. ONGOING ISSUES: Digital imagery applications will continue to present new opportunities and challenges. Position papers such as this are directed toward assisting the profession to stay informed and in control of these applications in the laboratory. Telecytology is an area in particular need of studies of good quality to provide data on factors affecting accuracy. New technologic approaches to addressing the issue of selective sampling in static image consultation are needed. The use of artificial intelligence software as an adjunct to enhance the accuracy and reproducibility of cytologic diagnosis of digital images in routine and consultation settings deserves to be pursued. Other telecytology-related issues that require clarification and the adoption of workable guidelines include interstate licensure and protocols to define malpractice liability.
Computer Communication Networks↗
Detection of high-risk human papillomavirus nucleic acid in archival cervical smears.
OBJECTIVE: To test the usefulness of a commercial DNA hybridization assay for the detection of high-risk (HR) human papillomavirus (HPV) types in archival cervical smears and to compare the sensitivity with that of polymerase chain reaction (PCR) using consensus primers. STUDY DESIGN: Stained material was scraped from archival slides and the pellet volume noted. DNA was extracted using silica/guanidinium isothiocyanate and the quality checked by amplification of the beta-globin gene. HR-HPV DNA was detected using a commercial hybrid capture assay (HCA) and the results compared with an in-house amplification system with consensus primers. RESULTS: Of 156 archival smears stored for 12-13 years, 20 were positive by HCA using an HR probe cocktail. Ninety-eight were also tested by PCR, and 35 were positive. The percentage of HPV-positive samples increased with the increasing size of the pellet. HR-HCA detected more positives in samples with high grade squamous intraepithelial lesion (moderate/severe dyskaryosis). CONCLUSION: Both hybridization by HCA and amplification by PCR could be used to detect genital HPV in archival smears. The general primers PCR detected more positives than HR-HCA but included HPV 6/11. While variation in sample size and prolonged storage may reduce the quality of DNA, the use of archival material for longitudinal studies of HPV presence is potentially worthwhile.
DNA, Viral↗
Computer-assisted quality assurance.
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False Negative Reactions↗
Would monolayers provide more representative samples and improved preparations for cervical screening? Overview and evaluation of systems available.
Conventional cervical smears prepared on site by the smear taker are subject to great variation in technical quality and allow little control of the critical parameters required for optimal microscopic diagnosis. More critical, however, is that a significant proportion of the cells removed from the cervix are discarded along with the collecting device and that the material placed on the slide is not transferred in a representative way and may not fully represent the cells removed from the cervix. If the cells were placed directly into preservative fluid, all the material scraped from the cervix would be sent to the laboratory in a well-preserved state, and fully representative slides could be prepared. Several studies have suggested that this would result in an increased cell harvest with a reduction of inadequate slides and an increase in the detection of abnormal cells. Automated preparation devices are now available. Two such devices, CytoRich and ThinPrep, were recently evaluated at the University of Edinburgh Department of Pathology (UEPD). The operational characteristics of each device were evaluated and consumables costed according to 1993-1994 prices. The consumables for the CytoRich were calculated to be more expensive, while operator time for the ThinPrep was more expensive. More mechanical problems were encountered with the ThinPrep, which was also considered more tedious to use. Cytotechnologists required considerable retraining before reaching competence in screening monolayers. They could assess them in approximately half the time required for conventional smears but found it more tiring. Almost no monolayer slides were considered unsatisfactory for laboratory interpretation due to the cells' being obscured by blood, pus or thick streaks of other cells. Scanty monolayers proved particularly difficult to read and interpret. Despite the bias introduced by using only the "leftover" material to make the monolayer, the diagnostic results of the monolayers from both devices were broadly similar to those for the matched split sample conventional smears. UEPD concluded that both devices produced monolayers that were adequate for diagnostic purposes. Neither device was ideal for routine laboratory use in cervical cytopathology in the model tested by UEPD, but both companies recently modified their devices in the light of the deficiencies identified by UEPD. The substantial loss of potentially diagnostic cells during the conventional transfer of cervical scrape material to glass slide alone merits consideration of alternative methods of preparation to obtain representative cell samples for optimal conventional microscopic diagnosis. Monolayers prepared by automated devices offer such an improvement for routine cervical cytopathology. The general deployment of such machines (involving substantial changes in the methods of working of laboratory staff responsible for tens of thousands of clinically important decisions each year) must await the completion of extensive and exhaustive laboratory and field trials. It is recommended that such trials be designed so that all the cellular material removed from the cervix is placed in the cell suspension, and the assessments should be carried out in a routine laboratory environment by cytotechnologists working in a routine cervical cytopathology service.
Evaluation Studies as Topic↗