Departmental audit in histopathology

Validation of digital pathology imaging for primary histopathological diagnosis

AIMS

Digital pathology (DP) offers advantages over glass slide microscopy (GS), but data demonstrating a statistically valid equivalent (i.e. non-inferior) performance of DP against GS are required to permit its use in diagnosis. The aim of this study is to provide evidence of non-inferiority.

METHODS AND RESULTS

Seventeen pathologists re-reported 3017 cases by DP. Of these, 1009 were re-reported by the same pathologist, and 2008 by a different pathologist. Re-examination of 10 138 scanned slides (2.22 terabytes) produced 72 variances between GS and DP reports, including 21 clinically significant variances. Ground truth lay with GS in 12 cases and with DP in nine cases. These results are within the 95% confidence interval for existing intraobserver and interobserver variability, proving that DP is non-inferior to GS. In three cases, the digital platform was deemed to be responsible for the variance, including a gastric biopsy, where Helicobacter pylori only became visible on slides scanned at the ×60 setting, and a bronchial biopsy and penile biopsy, where dysplasia was reported on DP but was not present on GS.

CONCLUSIONS

This is one of the largest studies proving that DP is equivalent to GS for the diagnosis of histopathology specimens. Error rates are similar in both platforms, although some problems e.g. detection of bacteria, are predictable.

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.

[Internal quality control of histological diagnosis in pathology. A nine-year experience]

Internal quality control (IQC) is a necessary component of total quality management. We report our experience with an internal audit scheme focusing on the histological diagnosis. We outline other strategies of IQC and analyze the causes of errors and ways to prevent them. Some practical guidelines to initiate this type of procedure are presented. Our audit was designed to check the accuracy of diagnosis, the clarity and completeness of the report, the quality of the documents leading to the diagnosis, and the turn-around time. It consisted of a retrospective analysis of 4185 randomly selected cases (representing 2% of all cases), over nine years. The control took place once a week and was done by two pathologists working as a team. The mean time spent by each pathologist was 45 minutes per week. Errors were scored using a 3-level grading scheme depending on their potential harm or impact on patient care. The overall rate of errors was 1.1%, and 0.1% of errors were potentially harmful to the patients. A single case (0.02%), in which a cancer was missed, had a real impact on patient care. Retrospective analysis of randomly selected cases mirrors the overall activity of a surgical pathology department. Nevertheless, each lab has to develop its own strategy of IQC, based on its size, its functioning, and its objectives. Although it may be difficult to initiate quality assurance when medical time is already limited, it is a helpful procedure in a more and more demanding medical and societal context and a pragmatic step towards "culture of quality".

Patient safety in anatomic pathology: measuring discrepancy frequencies and causes

CONTEXT

Anatomic pathology discrepancy frequencies have not been rigorously studied.

OBJECTIVE

To determine the frequency of anatomic pathology discrepancies and the causes of these discrepancies.

DESIGN

Participants in the College of American Pathologists Q-Probes program self-reported the number of anatomic pathology discrepancies in their laboratories by prospectively performing secondary review (post-sign-out) of 100 surgical pathology or cytology specimens. Reasons for the secondary review included conferences, external review, internal quality assurance policy, and physician request.

PARTICIPANTS

Seventy-four laboratories self-reported data.

MAIN OUTCOME MEASURES

Frequency of anatomic pathology discrepancy; type of discrepancy (ie, change in margin status, change in diagnosis, change in patient information, or typographic error); effect of discrepancy on patient outcome (ie, no harm, near miss, or harm); and clarity of report.

RESULTS

The mean and median laboratory discrepancy frequencies were 6.7% and 5.1%, respectively. Forty-eight percent of all discrepancies were due to a change within the same category of interpretation (eg, 1 tumor type was changed to another tumor type). Twenty-one percent of all discrepancies were due to a change across categories of interpretation (eg, a benign diagnosis was changed to a malignant diagnosis). Although the majority of discrepancies had no effect on patient care, 5.3% had a moderate or marked effect on patient care.Conclusions.-This study establishes a mean multi-institutional discrepancy frequency (related to secondary review) of 6.7%.

Anatomic Pathology Databases and Patient Safety

Context.—The utility of anatomic pathology discrepancies has not been rigorously studied.

Objective.—To outline how databases may be used to study anatomic pathology patient safety.

Design.—The Agency for Healthcare Research and Quality funded the creation of a national anatomic pathology errors database to establish benchmarks for error frequency. The database is used to track more frequent errors and errors that result in more serious harm, in order to design quality improvement interventions intended to reduce these types of errors. In the first year of funding, 4 institutions (University of Pittsburgh, Henry Ford Hospital, University of Iowa, and Western Pennsylvania Hospital) reported cytologic-histologic correlation error data after standardizing correlation methods. Root cause analysis was performed to determine sources of error, and error reduction plans were implemented.

Participants.—Four institutions self-reported anatomic pathology error data.

Main Outcome Measures.—Frequency of cytologic-histologic correlation error, case type, cause of error (sampling or interpretation), and effect of error on patient outcome (ie, no harm, near miss, and harm).

Results.—The institutional gynecologic cytologic-histologic correlation error frequency ranged from 0.17% to 0.63%, using the denominator of all Papanicolaou tests. Based on the nongynecologic cytologic-histologic correlation data, the specimen sites with the highest discrepancy frequency (by project site) were lung (ranging from 16.5% to 62.3% of all errors) and urinary bladder (ranging from 4.4% to 25.0%). Most errors detected by the gynecologic cytologic-histologic correlation process were no-harm events (ranging from 10.7% to 43.2% by project site). Root cause analysis identified sources of error on both the clinical and pathology sides of the process, and error intervention programs are currently being implemented to improve patient safety.

Conclusions.—A multi-institutional anatomic pathology error database may be used to benchmark practices and target specific high-frequency errors or errors with high clinical impact. These error reduction programs have national import.

Improving patient safety by examining pathology errors

A considerable void exists in the information available regarding anatomic pathology diagnostic errors and their impact on clinical outcomes. To fill this void and improve patient safety, four institutional pathology departments (University of Pittsburgh, Western Pennsylvania Hospital, University of Iowa Hospitals and Clinics, and Henry Ford Hospital System) have proposed the development of a voluntary, Web-based, multi-institutional database for the collection and analysis of diagnostic errors. These institutions intend to use these data proactively to implement internal changes in pathology practice and to measure the effect of such changes on errors and clinical outcomes. They believe that the successful implementation of this project will result in the study of other types of diagnostic pathology error and the expansion to national participation. The project will involve the collection of multi-institutional anatomic pathology diagnostic errors in a large database that will facilitate a more detailed analysis of these errors, including their effect on patient outcomes. Participating institutions will perform root cause analysis for diagnostic errors and plan and execute appropriate process changes aimed at error reduction. The success of these interventions will be tracked through analysis of postintervention error data collected in the database. Based on their preliminary studies, these institutions proposed the following specific aims: Specific aim #1: To use a Web-based database to collect diagnostic errors detected by cytologic histologic correlation and by second-pathologist review of conference cases. Specific aim #2: To analyze the collected error data quantitatively and generate quality performance reports that are useful for institutional quality improvement programs. Specific aim #3: To plan and implement interventions to reduce errors and improve clinical outcomes, based on information derived from root cause analysis of diagnostic errors. Specific aim #4: To assess the success of implemented interventions by quantitative measure of postinterventional errors and clinical outcomes and by qualitative assessment by project participants. Funding for this project was approved by the Agency for Health Care Research and Quality in September 2002, and data collection and analysis are ongoing. Over 5000 errors have been collected in the database, and the clinical outcomes of these errors have been tracked. At a national meeting in November 2003, root cause analysis was performed to determine causes of errors. The findings of these root cause analyses have been presented at national pathology meetings and are currently being published.

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.

Departmental audit in surgical anatomical pathology

Internal auditing of performance by pathology providers is a necessary component of total quality management. In this study a peer review of 10% of departmental surgical anatomical pathology accessions received over a seven month period was performed. A number of critical performance parameters were analysed including turn-around times, accuracy of reports and technical proficiency. The results demonstrated an approximate 2% significant error rate in macroscopic and microscopic descriptions, technically good quality sections and stains and generally satisfactory turn-around times. The value and costing of such an audit and changes initiated by the audit are discussed.

A questionnaire-based survey of errors in diagnostic histopathology throughout the United Kingdom

AIMS

To obtain a crude estimate of the rate at which consultant histopathologists become aware of errors in their work, and to gather information about the circumstances under which errors are made.

METHODS

A postal questionnaire was sent to all consultant histopathologists (1021) in the United Kingdom.

RESULTS

There was a 19.8% response to the questionnaire (202 returned). 119 pathologists reported 244 errors, 82 from within the preceding year. 42% of these errors had affected patient management. Pathologists usually blamed human error or excessive workload; however, data analysis did not reveal an excess of responses from laboratories with heavy workloads. A disproportionately large proportion of errors appear to be made in samples from the lymphoreticular system and by locum consultant pathologists.

CONCLUSIONS

This study undoubtedly suffered from reporting bias, but the figures suggest that a typical pathologist probably becomes aware of having made a serious diagnostic error approximately once per year. A larger, more systematic study of the circumstances under which errors are likely to occur appears to be justified but would require significant resources because of the large sample size required.