Assessing diagnostic errors: when is suspension of a pathologist justified?

External quality assurance as a revalidation method for pathologists in pediatric histopathology: Comparison of four international programs

AIM

External quality assurance (EQA) is an extremely valuable resource for clinical pathologists to maintain high standards, improve diagnostic skills, and possibly revalidate medical license. The aim of this study was to participate in and compare four international slide survey programs (UK, IAP-Germany, USA-Canada, Australasia) in pediatric histopathology for clinical pathologists with the aim to use it as a revalidation method.

METHODS

The following parameters were evaluated: number of circulations per year, number of slides, membership requirement, proof of significant pediatric pathology work, open to overseas participants, laboratory accreditation, issue of continuing professional development certificates and credits, slides discussion meeting, use of digital images, substandard performance letter, and anonymity of responses.

RESULTS

The UK scheme, which has sampling procedure over several time frames (2 circulations/year, 30 slides), partial confidentiality, and multiple sources of data and assessors, can be used as a model for revalidation. The US-Canadian and Australasian schemes only partially fulfill the revalidation requirements. The IAP scheme appears to be essentially an educational program and may be unsuitable for revalidation.

CONCLUSION

The purposes and programs of EQA schemes vary worldwide. In order for it to be used for revalidation, it is advisable that EQA schemes are immediately unified.

Diagnostic ‘errors’ in anatomical pathology: relevance to Australian laboratories

Failure to recognise that anatomical pathology diagnosis is a process of cognitive interpretation of the morphological features present in a small tissue sample has led to the public misperception that the process is infallible. The absence of a universally accepted definition of diagnostic error makes comparison of error rates impossible and one large study of laboratories in the United States shows a significant error rate of about 5%, most of which have no major impact on patient management. A recent review of the work of one pathologist in New South Wales confirms a lack of appreciation in medical administration that variable diagnostic thresholds result in an inherent fallibility of anatomical pathology diagnoses. The outcome of the review emphasises the need to educate both public and non-pathology colleagues of the nature of our work and brings into consideration the requirement to establish baseline error rates for Australian laboratories and the role of the Royal College of Pathologists of Australasia (RCPA) in developing fair and unbiased protocols for review of diagnostic errors. The responsibility of ensuring that diagnostic error rates are kept to the minimum is a shared one. Area health services must play their part by seeking to ensure that pathologists in any laboratory are not overworked and have adequate support and back-up from pathologists with expertise in specialised areas. It has been clearly enunciated by the Royal College of Pathologists in the United Kingdom that it is not safe for any histopathology service to be operated single-handedly by one histopathologist. Service managers and clinicians have to understand that country pathologists cannot provide the full range and depth of pathology expertise in the many clinical subspecialty areas that are often practised in non-metropolitan areas. Attending clinicians share the responsibility of accepting proffered pathology diagnoses only if it conforms to the clinical context. Pathology laboratories must continue to develop and maintain best-practice protocols and conduct periodic reviews of diagnosis, cytology-histology concordance, frozen section/permanent section correlations, conference reviews, intra and interdepartmental consultations, participate in external quality assurance programs and maintain ongoing education for all laboratory staff.

Inter-observer variation between general and specialist gastrointestinal pathologists when grading dysplasia in ulcerative colitis

Histological dysplasia is the cornerstone of colorectal cancer surveillance in ulcerative colitis (UC). Recently, pathologists have received unfavourable media attention concerning other cancer screening programmes. The aim of this study was to determine whether colonic biopsy specimens should be examined by gastrointestinal pathologists as opposed to generalists, by examining inter-observer variation between the two groups. Fifty-one coded slides showing varying degrees of dysplasia were mailed to seven gastrointestinal and six general histopathologists. Pathologists allocated each biopsy into one of four categories without the benefit of a clinical history or an opportunity to use the 'indefinite' category that is included in the Riddell classification. The responses were analysed using kappa statistics. The overall kappa statistic for gastrointestinal pathologists was 0.30 [95% confidence interval (CI)=0.26-0.34] and for general pathologists 0.28 (95% CI=0.23-0.32). Agreement was best for high-grade dysplasia (kappa of 0.54 and 0.61 for GI and general pathologists, respectively). There was total concordance of the 13 pathologists in only four of the 51 slides (7.8%) (95% CI=0.4-15.2%). It is concluded from these results that gastrointestinal pathologists are no better than generalists when grading dysplasia in UC and that agreement is poor in both groups. There is therefore no evidence that there would be any benefit in having specialist histopathology centres concentrating specifically on the interpretation of all surveillance colonoscopy biopsies from around the UK. It must be made clear to the public that surveillance and screening programmes carry a significant rate of histological error and that perfection cannot be expected or achieved with present methods.

A survey of biomedical scientists and consultant pathologists involved in the cervical screening programme

The past decade has seen a transformation in the National Health Service Cervical Screening Programme (NHSCSP) largely driven by responses to various screening scandals. Independent inquiries into these laboratory failures have identified a number of contributing factors. The aim of this postal survey was to determine how widespread these factors are throughout screening laboratories in England. The results indicate that issues around recruitment and retention of staff, the training of pathologists and low morale appear to be widespread. However, the results do not indicate a widespread breakdown in working relationships between consultants and biomedical scientists, although there is room for improvement in their relationships with hospital management. Finally, there seem to be mixed messages about the commitment of consultants to the screening programme.

Errors in histopathology reporting: detection and avoidance

The histopathological diagnosis is the bedrock of modern oncology, and plays a major role in the treatment of many other types of disease. Errors in these reports can critically affect patient care and may become the subject of media concern. This article considers how audit in histopathology can provide information about errors and inconsistencies in the diagnosis of surgical specimens. The use of audit to generate information about the background level of errors in pathology reports is reviewed, along with findings about the nature of these errors and the types of specimens more commonly affected. Generic audit strategies that can be used to minimize the risk of errors in reports are discussed, together with the use of audit to evaluate diagnostic criteria and pathological scoring or grading systems. The role of audit in determining the informational content of reports is included, and there is consideration of the relationship between sample size and error rates. The limited extent to which audit can be used to assess the performance of individual pathologists is also covered.