Method comparison in the clinical laboratory

Studies comparing a new method with an established method, to assess whether the new measurements are comparable with existing ones, are frequently conducted in clinical pathology laboratories. Assessment usually involves statistical analysis of paired results from the 2 methods to objectively investigate sources of analytical error (total, random, and systematic). In this review article, the types of errors that can be assessed in performing this task are described, and a general protocol for comparison of quantitative methods is recommended. The typical protocol has 9 steps: 1) state the purpose of the experiment, 2) establish a theoretical basis for the method comparison experiment, 3) become familiar with the new method, 4) obtain estimates of random error for both methods, 5) estimate the number of samples to be included in the method comparison experiment, 6) define acceptable difference between the 2 methods, 7) measure the patient samples, 8) analyze the data, and 9) judge acceptability. The protocol includes the essential investigations and decisions needed to objectively assess the overall analytical performance of a new method compared to a reference or established method. The choice of statistical methods and recommendations of decision criteria within the stages are discussed. Use of the protocol for decision-making is exemplified by the comparison of 2 methods for measuring alanine aminotransferase activity in serum from dogs. Finally, a protocol for comparing simpler semiquantitative methods with established methods that measure on a continuous scale is suggested.

Interobserver variation among histopathologic evaluations of intestinal tissues from dogs and cats

OBJECTIVE

To determine whether substantial interobserver variation exists among diagnostic pathologists for descriptions of intestinal mucosal cell populations and whether histopathologic descriptions accurately predict when a patient does not have clinically evident intestinal disease.

DESIGN

Comparative survey. Sample Population-14 histologic slides of duodenal, ileal, or colonic tissue from 10 dogs and 3 cats.

PROCEDURE

Each histologic slide was evaluated independently by 5 pathologists at 4 institutions. Pathologists, who had no knowledge of the tissues' origin, indicated whether slides were adequate for histologic evaluation and whether the tissue was normal or abnormal. They also identified the main infiltrating cell type in specimens that were considered abnormal, and whether infiltrates were mild, moderate, severe, or neoplastic.

RESULTS

Quality of all slides was considered adequate or superior by at least 4 of the 5 pathologists. For intensity of mucosal cellular infiltrates, there was uniformity of opinion for 1 slide, near-uniformity for 6 slides, and nonuniformity for 7 slides. Five dogs did not have clinical evidence of intestinal disease, yet the pathologists' descriptions indicated that their intestinal tissue specimens were abnormal.

CONCLUSIONS AND CLINICAL RELEVANCE

Substantial interobserver variation was detected. Standardization of pathologic descriptions of intestinal tissue is necessary for meaningful comparisons with published articles. Clinicians must be cautious about correlating clinical signs and histopathologic descriptions of intestinal biopsy specimens.

Variation among Pathologists in Histologic Grading of Canine Cutaneous Mast Cell Tumors

Ten veterinary pathologists at 1 veterinary institution independently assigned histologic grades to the same 60 canine cutaneous mast cell tumors (MCTs). There was significant variation among pathologists in grading the MCTs ( P < 0.001). The probability of assigning a low grade was significantly higher for the pathologists in this study who use a published reference for histologic grading of canine cutaneous MCTs that allows subcutaneous MCTs or MCTs with mitotic figures to be included in the low-grade category ( P < 0.0001 and P < 0.0001, respectively).

Cytologic diagnosis: expression of probability by clinical pathologists

BACKGROUND

Clinical pathologists use descriptive terms or modifiers to express the probability or likelihood of a cytologic diagnosis. Words are imprecise in meaning, however, and may be used and interpreted differently by pathologists and clinicians.

OBJECTIVES

The goals of this study were to 1) assess the frequency of use of 18 modifiers, 2) determine the probability of a positive diagnosis implied by the modifiers, 3) identify preferred modifiers for different levels of probability, 4) ascertain the importance of factors that affect expression of diagnostic certainty, and 5) evaluate differences based on gender, employment, and experience.

METHODS

We surveyed 202 clinical pathologists who were board-certified by the American College of Veterinary Pathologists (Clinical Pathology). Surveys were distributed in October 2001 and returned by e-mail, fax, or surface mail over a 2-month period. Results were analyzed by parametric and nonparametric tests.

RESULTS

Survey response rate was 47.5% (n = 96) and primarily included clinical pathologists at veterinary schools (n = 58) and diagnostic laboratories (n = 31). Eleven of 18 terms were used "often" or "sometimes" by >/= 50% of respondents. Broad variability was found in the probability assigned to each term, especially those with median values of 75 to 90%. Preferred modifiers for 7 numerical probabilities ranging from 0 to 100% included 68 unique terms; however, a set of 10 terms was used by >/= 50% of respondents. Cellularity and quality of the sample, experience of the pathologist, and implications of the diagnosis were the most important factors affecting the expression of probability.

CONCLUSION

Because of wide discrepancy in the implied likelihood of a diagnosis using words, defined terminology and controlled vocabulary may be useful in improving communication and the quality of data in cytology reporting.

Teaching medical pathology in the twenty-first century: virtual microscopy applications

Virtual microscopy (VM) has been implemented and evaluated in the histology and general and systemic pathology courses at the University of Iowa Carver College of Medicine. Advantages of VM over traditional microscopy include accessibility and efficiency of learning and the ability to integrate VM with computer-assisted interactive learning. Advantages of using VM as opposed to digital photomicrographs include the ability to pan and zoom, explore the slide, and make independent observations. Although VM is used in a case-based format for teaching histopathology to medical students at the University of Iowa, VM may also be effectively implemented in other medical-student teaching models, including integrated and problem-based learning curricula and the classical pathology laboratory. Additional Iowa venues and courses using VM teaching include pathology of human disease for bioscience graduate students, cytology education, a comparative pathology research resource, and histology and histopathology for veterinary medicine. This article reviews the history and evolution of VM in medical pathology and its implementation at Iowa.

Harmonization of immunotoxicity guidelines in the ICH process--pathology considerations from the guideline Committee of the European Society of Toxicological Pathology (ESTP)

As part of the ICH process of harmonization of testing guidelines for immunotoxicity, the European Society of Toxicologic Pathology (ESTP) has contributed to the scientific discussion on methods and evaluation of immunotoxicity studies with technical and scientific recommendations on toxicologic pathology. The weighing and sampling of immune organs is discussed taking into consideration specifically the value of lymph node weighing and the selection of appropriate lymph nodes for the detection of local and systemic effects. The different techniques of bone marrow preparation are considered for routine and extended investigations. Criteria are given for the gross and histopathological detection of effects in Peyer's patches. For the histopathological evaluation it is strongly recommended that each compartment within the different lymphoid organs is investigated separately and semiquantitatively since this approach has shown to increase the sensitivity and specificity of immunohistopathology.

An impending crisis in the provision of histopathology expertise for mouse functional genomics

The generation of new mouse models of human disease is accelerating rapidly, due to the completion of whole-genome sequencing efforts and technological advances in the manipulation of the mouse genome. We sought to investigate manpower issues in the provision of histopathology expertise for mouse functional genomics and compared this to the perceived demand from principal investigators (PIs). Through the European Commission (EC)-funded PRIME pathology training initiative, two questionnaires were devised to collect information from pathologists and EC-funded PIs on the current provision of mouse histopathology expertise in Europe and the demands for this service. We find that pathological analysis is being performed almost exclusively by professionally qualified pathologists, generally employed in clinical diagnostic posts, where the work is undertaken as collaboration outside of their contractual commitments but without previous training in veterinary or comparative pathology. The results indicate that there is a lack of both trainees and provision of specialist training in this field. Unsurprisingly, the availability of diagnostic expertise and advice falls far short of the number of genetically engineered mice (GEM) being generated for analysis. We analyse these results with reference to previous studies and discuss solutions for the future recruitment, training and funding for pathologists in mouse functional genomics in Europe.

Postgraduate training programs in veterinary clinical pathology in the United States and Canada (1998 to 2002)

BACKGROUND

Residency and graduate programs in veterinary clinical pathology provide specialized training for board certification and are important pathways to careers in clinical pathology diagnostics, teaching, and research. Information about training opportunities is useful for assessing disciplinary needs, outcomes, and changes, garnering program support, and providing objective data for program evaluation by faculty, trainees, and prospective applicants.

OBJECTIVES

The goals of this study were to 1) compile detailed information on the number and types of postgraduate training programs in veterinary clinical pathology in the United States and Canada, 2) describe the goals, activities, strengths, and weaknesses of the programs, 3) assess the desirability of program accreditation and program standards, 4) identify supplemental training opportunities, and 5) evaluate changes in programs, trainees, and faculty 4 years later.

METHODS

In July 1998, the American Society for Veterinary Clinical Pathology Education Committee sent a survey to representatives at the 31 schools and colleges of veterinary medicine in the United States and Canada and 31 diagnostic laboratories, private hospitals, and pharmaceutical companies. Survey data were compared with updated information obtained from training program coordinators in November 2002.

RESULTS

Survey response rate was 94% for universities, 39% for nonuniversity institutions, and 66% overall. In 1998, there were 20 clinical pathology training programs, including residencies (n=10) and graduate programs combined with residency training (n=10), with 36 total training positions. In 2002, there were 25 training programs (14 residencies, 11 combined), with 52 total positions. The median faculty:trainee ratio was 2.0 in both years. Of 67 faculty members involved in training in 1998, 57 (85.1%) were board-certified in clinical pathology and 53 (79.1%) had DVM/PhD degrees. Net faculty numbers increased by 17 (25.4%) but the median per institution remained at 3.0. Primary program goals were 1) eligibility for and successful achievement of board certification in clinical pathology by the American College of Veterinary Pathologists, 2) proficiency in laboratory diagnostics, and 3) contemporary basic or applied research training. Many programs cited research opportunities, caseloads, and training in hematology and cytology as strengths. Program weaknesses included insufficient funding, too few faculty, and limited training in clinical chemistry and laboratory operations/quality assurance. Trainees completing programs within the past 5 years (n=70) were employed in academia (28.6%), diagnostic laboratories (32.9%), and industry (18.6%). For trainees completing programs between 1999 and 2002 (n=38), these percentages were 52.6%, 21.1%, and 7.9%, respectively. Most (62.5%) respondents supported program standards and accreditation, and 76% supported board review sessions for trainees.

CONCLUSIONS

Opportunities for postgraduate training in veterinary clinical pathology increased between 1998 and 2002, with 5 new programs and 16 new training positions. These additions and the increased emphasis on diagnostic proficiency, efforts to strengthen training in clinical chemistry and quality assurance, and continuation of combined PhD-residency programs will help address the perceived need for increased numbers of qualified clinical pathologists in academia, diagnostic laboratories, and industry.

Guidelines for resident training in veterinary clinical pathology. I. Clinical chemistry

BACKGROUND

The Education Committee of the American Society for Veterinary Clinical Pathology identified a need for improved structure and guidance of clinical pathology resident training in clinical chemistry.

OBJECTIVES

The committee's goal was to develop learning objectives and competencies in knowledge, abilities, and skills in clinical chemistry; provide options and ideas for training activities; and identify clinical chemistry resources useful for clinical pathology faculty, training program coordinators, and residents.

METHODS

Guidelines were developed and written with the input of Education Committee members and peer experts.

RESULTS

The primary objectives of clinical chemistry training are: 1) to accrue a thorough, extensive, and relevant knowledge base of the types, principles, and properties of clinical chemistry tests and concepts of pathophysiology in animals; 2) to develop abilities to reason, think critically, and exercise judgment in clinical chemistry data interpretation, investigative problem-solving, and hypothesis-driven research; and 3) to acquire technical and statistical skills important in clinical chemistry and laboratory operations.

CONCLUSIONS

These guidelines define expected competencies that will help ensure proficiency, leadership, and the advancement of knowledge in veterinary clinical chemistry and provide a useful framework for didactic and clinical activities in resident training programs. The learning objectives can readily be adapted to institutional and individual needs, interests, goals, and resources.

Veterinary pathology in the United Kingdom: past, present, and future

This article presents a historical perspective on veterinary anatomic pathology in the United Kingdom from the late nineteenth century to the present. Prior to World War II, the specialty was a rather general one that also included bacteriology and parasitology and was only slightly affected by strong Germanic developments in cell and tissue pathology. The few notable figures of this era include John McFadyean, Sidney Gaiger, and J.R.M Innes. The specialty developed strongly in the second half of the twentieth century, led by a small number of individuals, and was greatly aided by the development of specialist colleges and residency training. Key individuals of this era include W.F. Blakemore, Ernest Cotchin, R.J.M. Franklin, W.F.H. Jarrett, A.R. Jennings, and A.C. Palmer. A remarkable feature of this period has been the increased employment of veterinary pathologists in biomedical industry and in private diagnostic laboratories. While standards of pathology practice have benefited from the college initiatives, there are major financial constraints on the availability of funded training posts in the United Kingdom, and there remain considerable shortages in the supply of pathologists trained to contemporary standards. The acknowledged professional and scientific importance of veterinary pathology needs to be translated into effective financial support for the training that underpins competence in this specialty. Further developments seem likely to be dominated by advances in the technology of tissue handling, applications of molecular biology to pathology, and greater use of telepathology in teaching, in quality assurance, and in continuing professional development.

Integrated Case-Based Applied Pathology (ICAP): a diagnostic-approach model for the learning and teaching of veterinary pathology

Integrative Case-Based Applied Pathology (ICAP) cases form one component of learning and understanding the role of pathology in the veterinary diagnostic process at the Faculty of Veterinary Science, University of Sydney. It is a strategy that focuses on student-centered learning in a problem-solving context in the year 3 curriculum. Learning exercises use real case material and are primarily delivered online, providing flexibility for students with differing learning needs, who are supported by online, peer, and tutor support. The strategy relies heavily on the integration of pre-clinical and para-clinical information with the introduction of clinical material for the purposes of a logical three-level, problem-oriented approach to the diagnosis of disease. The focus is on logical diagnostic problem solving, primarily using gross pathology and histopathological material, with the inclusion of microbiological, parasitological, and clinical pathological data. The ICAP approach is linked to and congruent with the problem-oriented approach adopted in veterinary medicine and the case-based format used by one of the authors (PJC) for the teaching and learning of veterinary clinical pathology in year 4. Additionally, final-year students have the opportunity, during a diagnostic pathology rotation, to assist in the development and refinement of further ICAPs, which reinforces the importance of pathology in the veterinary diagnostic process. Evidence of the impact of the ICAP approach, based primarily on student surveys and staff peer feedback collected over five years, shows that discipline-specific learning, vertical and horizontal integration, alignment of learning outcomes and assessment, and both veterinary and generic graduate attributes were enhanced. Areas for improvement were identified in the approach, most specifically related to assistance in the development of generic teamwork skills.

Guidelines for resident training in veterinary clinical pathology. II. Hematology

BACKGROUND

The Education Committee of the American Society for Veterinary Clinical Pathology (ASVCP) identified a need for improved structure and guidance in training residents in clinical pathology. To begin to meet this need, guidelines for training in clinical chemistry were published in 2003.

OBJECTIVE

The goal of this report is to define learning objectives and competencies in hematology, including coagulation and immunohematology.

METHODS

These guidelines were developed and written with the input of ASVCP Education Committee members and peer experts.

RESULTS

The primary objectives of training in hematology are: 1) to accrue a thorough, extensive, and relevant knowledge base of the types, principles, and properties of hematology tests and concepts of pathophysiology in animals; 2) to develop abilities to reason, think critically, communicate effectively, and exercise judgment in hematologic data interpretation and investigative problem-solving; and 3) to acquire technical and statistical skills important in hematology and laboratory operations. We also provide options and ideas for training activities and identify hematology resources useful for clinical pathology faculty and staff, training program coordinators, and residents.

CONCLUSIONS

The guidelines define expected competencies that will help ensure proficiency, leadership, and the advancement of knowledge in veterinary hematology and provide a useful framework for didactic and clinical activities in resident-training programs. The learning objectives can readily be adapted to institutional and individual needs, interests, goals, and resources.

The European College of Veterinary Pathologists (ECVP): the professional body for European veterinary pathologists

The European College of Veterinary Pathologists (ECVP) was established in 1995 with the aim of advancing veterinary pathology and promoting high standards within the specialty in Europe. The ECVP is one of 21 European colleges recognized by the European Board of Veterinary Specialisation (EBVS), which represents a quality-assurance system for European veterinary specialists. Until the ECVP was founded, there was no unified European system recognizing the specialty of pathology, and many European countries followed their own qualification systems, which varied in form and standard. The ECVP provides an annual certifying examination, the passing of which is required to gain membership (diplomate status) in the college. This qualification is now accepted on equal terms by the well-established American College of Veterinary Pathologists (ACVP). In line with EBVS requirements, the ECVP has also established a standard continuing professional development (CPD) and re-registration system for its membership. Furthermore, it has promoted and unified European post-graduate training in veterinary pathology by setting up requirements for residency training programs and making registration and monitoring of these programs by the ECVP a prerequisite for approval of an institution as a training facility. The concurrent establishment, together with the European Society of Veterinary Pathology, of an annual summer school that trains residents for the certifying examination has further fostered European post-graduate training. Within 10 years, the ECVP has succeeded in establishing common standards and a unified approach to veterinary pathology throughout Europe. This article describes the evolution and organization of the ECVP.

Historical perspective and future directions in training of veterinary pathologists with an emphasis on zoo and wildlife species

This article discusses the history of the field of zoo and wildlife pathology, training opportunities for veterinary students and graduate veterinarians, and current and future job opportunities. The niches occupied by veterinarians in this field and their contributions to animal and human health are also highlighted. The field of zoo and wildlife, or "non-traditional" species, pathology has its roots in comparative anatomy, zoology, wildlife biology, and medical pathology in the mid- to late nineteenth century. The initial emphasis was on comparisons between animal and human diseases or on management of game animals. Veterinarians became increasingly involved during the twentieth century, gradually changing the emphasis to improvement of conservation strategies, captive care, and elucidation of diseases of concern for the animals themselves. Currently there are several zoos and wildlife agencies in the United States employing full-time veterinary pathologists. Private and government diagnostic laboratories, veterinary schools, and other academic institutions in the United States with pathology departments are other employers. The field requires post-DVM training by means of a residency program leading to board certification, graduate school (MS or PhD degrees), or both. Veterinary students can gain valuable experience in the field through externships and, at some schools, through elective courses in the curriculum. Current concerns about ecosystem health, bioterrorism, and the recognition that captive and free-ranging wildlife can serve as sentinel species will increase the demand for veterinary pathologists choosing this very rewarding career path specializing in non-traditional species.

Providing high-quality research training for veterinary pathologists in Europe

Despite their key role in a wide range of fields relating to animal and public health, there is currently a lack of veterinary pathologists in Europe. In 1999, to help address the problem, the European College of Veterinary Pathologists (ECVP) and the European Society of Veterinary Pathology (ESVP) established a joint Education Committee. In this Special Article, Professor Anja Kipar and colleagues, all members of the committee, describe the ECVP/ESVP Summer Schools in Veterinary Pathology programme, which aims to provide high-quality research training for veterinary pathologists from all over Europe and beyond.