The World Health Organization Reporting System for Pancreaticobiliary Cytopathology: Overview and Summary.

The recently published WHO Reporting System for Pancreaticobiliary Cytopathology (World Health Organization [WHO] System) is an international approach to the standardized reporting of pancreaticobiliary cytopathology, updating the Papanicolaou Society of Cytopathology System for Reporting Pancreaticobiliary Cytology (PSC System). Significant changes were made to the categorization of benign neoplasms, intraductal neoplasms, mucinous cystic neoplasms, and malignant neoplasms considered low grade. Benign neoplasms, such as serous cystadenoma, categorized as Neoplastic: benign in the PSC system, are categorized as Benign/negative for malignancy in the WHO system. Pancreatic neuroendocrine tumor, solid-pseudopapillary neoplasm, and gastrointestinal stromal tumor, categorized as Neoplastic: other in the PSC system, are categorized as Malignant in the WHO System in accord with their classification in the 5th edition WHO Classification of Digestive System Tumours (2019). The two new categories of Pancreaticobiliary Neoplasm Low-risk/grade and Pancreaticobiliary Neoplasm High-risk/grade are mostly limited to intraductal neoplasms and mucinous cystic neoplasms. Low-risk/grade lesions are mucinous cysts, with or without low-grade epithelial atypia. High-risk/grade lesions contain neoplastic epithelium with high-grade epithelial atypia. Correlation with clinical, imaging, and ancillary studies remains a key tenet. The sections for each entity are written to highlight key cytopathological features and cytopathological differential diagnoses with the pathologist working in low resource setting in mind. Each section also includes the most pertinent ancillary studies useful for the differential diagnosis. Sample reports are provided for each category. Finally, the book provides a separate section with risk of malignancy and management recommendations for each category to facilitate decision-making for clinicians.

Pattern recognition of hematological profiles of tumors of the digestive tract: an exploratory study.

Aims: In this study, we aimed to apply laboratory blood analysis to identify the hematological (based on hemoglobin concentration, erythrocytes, hematocrit, and RDW count) profiles associated with the most prevalent forms of digestive tract malignancies. Furthermore, we aimed to evaluate how these profiles contributed to distinguishing these tumors at diagnosis. Methods: We collected data from the date of ICD-10 diagnostic coding for C15 esophagus, C16 stomach, C18 colon, and C19 rectum tumors of 184 individuals. The statistical analysis and data visualization approaches, notably the heat map and principal component analysis (PCA), allowed for creating a summary hematological profile and identifying the most associated parameters for each pathologic state. Univariate and multivariate data modeling and ROC analysis were performed in both SPSS and Python. Results: Our data reveal unique patterns based on tumor development anatomical location, clustering the C18 colon and C19 rectum from the C15 esophagus and C16 stomach. We found a significant difference between C16 stomach carcinoma and the other tumors, which substantially correlated with raised RDW in conjunction with low hemoglobin concentration, erythrocytes, and hematocrit counts. In contrast, C18 colon carcinoma had the higher red blood cell count, allowing for the best classification metrics in the test set of the binary logistic regression (LR) model, accounting for an AUC of 0.77 with 94% sensitivity and 52% specificity. Conclusion: This study emphasizes the significance of adding hematological patterns in diagnosing these malignancies, which could path further investigations regarding profiling and monitoring at the point of care.

Polymerase chain reaction for the in vitro detection of the pESI plasmid associated with the globally circulating Salmonella Infantis outbreak strain.

A globally circulating strain of Salmonella enterica serotype Infantis containing the pESI plasmid has increased in prevalence in poultry meat samples and cases of human infections. In this study, a polymerase chain reaction (PCR) protocol was designed to detect the pESI plasmid and confirm the Infantis serotype of Salmonella isolates. Primers were tested bioinformatically to predict specificity, sensitivity, and precision. A total of 54 isolates of Salmonella serotypes Infantis, Senftenberg, and Alachua were tested, with and without the pESI plasmid carriage. Isolates of 31 additional serotypes were also screened to confirm specificity to Infantis. Specificity, sensitivity, and precision of each primer were >0.95. All isolates tested produced the expected band sizes. This PCR protocol provides a rapid and clear result for the detection of the pESI plasmid and serotype Infantis and will allow for the in vitro detection for epidemiological studies where whole-genome sequencing is not available.

Taxonomic review of the Andean crab spiders genus Coenypha Simon, 1895 (Thomisidae: Stephanopinae).

The genus Coenypha Simon, 1895 is composed of species distributed on the Southern Andean Region and Patagonia, and presents remarkable somatic morphologies, such as the flattened habitus, enlarged femora I, and a wide opisthosoma. Molecular and morphology-based phylogenies have revealed the close relationship of this genus with sympatric species previously assigned to Stephanopis O. Pickard-Cambridge, 1869. Our recent cladistic analysis extended such preliminary results in recovering numerous morphological characters as synapomorphies of a well-supported clade, thus justifying the transfer of all species of 'Andean Stephanopis' to Coenypha. In the present work, we provide a taxonomic review of these species, update their diagnoses, descriptions and illustrate them through detailed photographs. New distribution records are presented, the male of C. antennata (Tullgren, 1902) is described for the first time, and two new species are described based on both sexes (Coenypha trapezium sp. nov. and Coenypha foliacea sp. nov.). Stephanopis exigua (Nicolet, 1849) is considered a nomen dubium. Stephanopis verrucosa (Nicolet, 1849), Thomisus spectrum Nicolet, 1849, and T. pubescens Nicolet, 1849 are synonymized with Coenypha nodosa (Nicolet, 1849). The synonymy of Thomisus nicoleti Roewer, 1951 (a replaced name for T. cinereus Nicolet, 1849 due to a homonymy) with Misumenops temibilis (Holmberg, 1876) is rejected, and considered together with Stephanopis spissa (Nicolet, 1849), Thomisus variabilis Nicolet, 1849 and Stephanopis maulliniana Mello-Leitão, 1951, synonyms of Coenypha ditissima (Nicolet, 1849); Stephanopis badia Keyserling, 1880 is transferred to Sidymella Strand, 1942.

A brief review of the WHO reporting system for pancreaticobiliary cytopathology.

The World Health Organization (WHO), the International Academy of Cytology, and the International Agency for Research on Cancer have developed an approach to standardized reporting of pancreaticobiliary cytopathology. The WHO Reporting System for Pancreaticobiliary Cytopathology (WHO System) revises the Papanicolaou Society of Cytopathology (PSC) System for Reporting Pancreaticobiliary Cytology published in 2015 and replaces the 6 PSC categories with 7 categories: "Insufficient/Inadequate/Nondiagnostic"; "Benign/Negative for malignancy"; "Atypical"; "Pancreaticobiliary neoplasm, low risk/grade (PaN-low)"; "Pancreatic neoplasm, high risk/grade (PaN-High)"; "Suspicious for malignancy"; and "Malignant". In the PSC system, there is a single category for "Neoplastic" lesions that includes 2 groups, 1 for benign neoplasms and 1 named "Neoplastic-other", dominated by premalignant intraductal neoplasms primarily intraductal papillary mucinous neoplasms and low-grade malignant neoplasms (pancreatic neuroendocrine tumors (PanNET) and solid pseudopapillary neoplasms (SPN). In the WHO System, benign neoplasms with virtually no risk of malignancy are included in the "Benign" category and low-grade malignancies (PanNET and SPN) are included in the "Malignant" category, as per the 5th edition of the WHO Classification of Digestive System Tumors, while the non-invasive pre-malignant lesions of the ducts are divided by the cytomorphological grade of the epithelium into PaN-low and PaN-high with distinctly different risks of malignancy. Within each category, key diagnostic cytopathologic features and the ancillary studies for diagnostic and prognostic evaluation, as well as the implications of diagnosis for patient care and management, are outlined. Reporting and diagnostic management options recognize the variations in the availability of diagnostic and prognostic ancillary testing modalities in low- and middle-income countries.

Spontaneous Genomic Variation as a Survival Strategy of Nosocomial Staphylococcus haemolyticus.

Staphylococcus haemolyticus is one of the most important nosocomial human pathogens frequently isolated in bloodstream and medical device-related infections. However, its mechanisms of evolution and adaptation are still poorly explored. To characterize the strategies of genetic and phenotypic diversity in S. haemolyticus, we analyzed an invasive strain for genetic and phenotypic stability after serial passage in vitro in the absence and presence of beta-lactam antibiotics. We performed pulsed-field gel electrophoresis (PFGE) of the culture and analyzed five colonies at seven time points during stability assays for beta-lactam susceptibility, hemolysis, mannitol fermentation, and biofilm production. We compared their whole genomes and performed phylogenetic analysis based on core single-nucleotide polymorphisms (SNPs). We observed a high instability in the PFGE profiles at the different time points in the absence of antibiotic. Analysis of WGS data for individual colonies showed the occurrence of six large-scale genomic deletions within the oriC environ, smaller deletions in non-oriC environ regions, and nonsynonymous mutations in clinically relevant genes. The regions of deletion and point mutations included genes encoding amino acid and metal transporters, resistance to environmental stress and beta-lactams, virulence, mannitol fermentation, metabolic processes, and insertion sequence (IS) elements. Parallel variation was detected in clinically significant phenotypic traits such as mannitol fermentation, hemolysis, and biofilm formation. In the presence of oxacillin, PFGE profiles were overall stable over time and mainly corresponded to a single genomic variant. Our results suggest that S. haemolyticus populations are composed of subpopulations of genetic and phenotypic variants. The maintenance of subpopulations in different physiological states may be a strategy to adapt rapidly to stress situations imposed by the host, particularly in the hospital environment. IMPORTANCE The introduction of medical devices and antibiotics into clinical practice have substantially improved patient quality of life and contributed to extended life expectancy. One of its most cumbersome consequences was the emergence of medical device-associated infections caused by multidrug-resistant and opportunistic bacteria such as Staphylococcus haemolyticus. However, the reason for this bacterium's success is still elusive. We found that in the absence of environmental stresses, S. haemolyticus can spontaneously produce subpopulations of genomic and phenotypic variants with deletions/mutations in clinically relevant genes. However, when exposed to selective pressures, such as the presence of antibiotics, a single genomic variant will be recruited and become dominant. We suggest that the maintenance of these cell subpopulations in different physiological states is an extremely effective strategy to adapt to stresses imposed by the host or the infection environment and might contribute for S. haemolyticus survival and persistence in the hospital.

Non-Destructive Inspection of High Temperature Piping Combining Ultrasound and Eddy Current Testing.

This paper presents an automated Non-Destructive Testing (NDT) system for the in-service inspection of orbital welds on tubular components operating at temperatures as high as 200 °C. The combination of two different NDT methods and respective inspection systems is here proposed to cover the detection of all potential defective weld conditions. The proposed NDT system combines ultrasounds and Eddy current techniques with dedicated approaches for dealing with high temperature conditions. Phased array ultrasound was employed, searching for volumetric defects within the weld bead volume while Eddy currents were used to look for surface and sub-surface cracks. The results from the phased array ultrasound results showed the effectiveness of the cooling mechanisms and that temperature effects on sound attenuation can be easily compensated for up to 200 °C. The Eddy current results showed almost no influence when temperatures were raised up to 300 °C.

Prevalence Rate of Thalassemia Carriers among Individuals with Microcytosis or Hypochromia in Portugal.

INTRODUCTION: Microcytosis and hypochromia result from deficient hemoglobin synthesis in red blood cells and are easily detected in a complete blood count test. These conditions are mainly due to iron nutritional deficiency, but may also result from some genetic diseases, such as thalassemia. The aim of this study was to determine the contribution of ß- and α-thalassemia to these abnormal hematological phenotypes in a representative sample of adult individuals living in Portugal who participated in the first Portuguese National Health Examination Survey (INSEF). MATERIAL AND METHODS: Among the 4808 INSEF participants, 204 had microcytosis, hypochromia or both. The corresponding 204 DNAs were screened for changes in the ß-globin gene by next-generation sequencing and Sanger sequencing. In addition, α-thalassemia deletions within the α-globin cluster were investigated by Gap-PCR and multiplex ligation-dependent probe amplification. RESULTS: In this selected subgroup of INSEF participants, 54 had α-thalassemia (26%), predominantly caused by the -α3.7kb deletion, and 22 were ß-thalassemia carriers (11%) mainly due to point mutations in the ß-globin gene previously known in Portugal. CONCLUSION: Thalassemia trait is a frequent cause of microcytosis or hypochromia in Portugal since this genetic condition was found in 37% of the investigated cases.

Prevalência de aleitamento materno exclusivo e fatores associados em um município do extremo sul catarinense / Prevalence of exclusive breastfeeding and associated factors in a city of southern of Santa Catarina State, Brazil

Identificar a prevalência de aleitamento materno exclusivo e fatores relacionados durante os seis primeiros meses de vida do lactente. Trata-se de um estudo transversal realizado com 102 nutrizes residentes no município de Balneário Gaivota(SC) que efetivaram o pré-natal na rede pública ou privada e tiveram parto no ano de 2018. Os dados foram coletados por aplicação de questionário contemplando as variáveis sociodemográficas, gestacionais e pós-gestacionais. A prevalência de aleitamento materno exclusivo foi de 43,1%. Aqueles bebês que usavam mamadeira tiveram 45% menos probabilidade de ter recebido aleitamento materno exclusivo até os 6 meses de idade, e aqueles que receberam prescrição de fórmula infantil na alta hospitalar apresentaram 54% menos chance comparados aos seus pares. Os fatores relacionados ao aleitamento materno exclusivo são comportamentais e modificáveis, sendo necessária a orientação pelos profissionais de saúde durante a consulta pré-natal, puericultura e no acompanhamento do desenvolvimento infantil.

To identify the prevalence of exclusive breastfeeding and its related factors during the first six months of the infant's life. This is a cross-sectional study carried out with 102 nursing mothers residing in the city of Balneário Gaivota( SC) who performed prenatal care in the public or private network and gave birth in 2018. Data were collected by application of a questionnaire and included sociodemographic, gestational and post-gestational variables. The prevalence of exclusive breastfeeding was 43.1%. Those babies who used a bottle were 45% less likely to have been exclusively breastfed up to six months of age, and those who were prescribed infant formula at hospital discharge were 54% less likely compared to their peers. Factors related to exclusive breastfeeding are behavioral and modifiable, thus, guidance by health professionals is necessary during prenatal and childcare consultations and in the monitoring of child development.

Deep Learning Framework for Controlling Work Sequence in Collaborative Human-Robot Assembly Processes.

The human-robot collaboration (HRC) solutions presented so far have the disadvantage that the interaction between humans and robots is based on the human's state or on specific gestures purposely performed by the human, thus increasing the time required to perform a task and slowing down the pace of human labor, making such solutions uninteresting. In this study, a different concept of the HRC system is introduced, consisting of an HRC framework for managing assembly processes that are executed simultaneously or individually by humans and robots. This HRC framework based on deep learning models uses only one type of data, RGB camera data, to make predictions about the collaborative workspace and human action, and consequently manage the assembly process. To validate the HRC framework, an industrial HRC demonstrator was built to assemble a mechanical component. Four different HRC frameworks were created based on the convolutional neural network (CNN) model structures: Faster R-CNN ResNet-50 and ResNet-101, YOLOv2 and YOLOv3. The HRC framework with YOLOv3 structure showed the best performance, showing a mean average performance of 72.26% and allowed the HRC industrial demonstrator to successfully complete all assembly tasks within a desired time window. The HRC framework has proven effective for industrial assembly applications.

The World Health Organization Reporting System for Pancreaticobiliary Cytopathology.

The World Health Organization (WHO), the International Academy of Cytology, and the International Agency for Research on Cancer, with expert contributors from around the world, present an international approach to standardized reporting of pancreaticobiliary cytopathology. This reporting system is one of the first in a series from various body sites that mirror the WHO Classification of Tumours series and provides an evidence-based terminology system with associated risk of malignancy and diagnostic management recommendation per diagnostic category. The WHO Reporting System for Pancreaticobiliary Cytopathology (WHO system) revises the Papanicolaou Society of Cytopathology (PSC) system for Reporting Pancreaticobiliary Cytology published in 2015 and replaces the six-tiered system with a seven-tiered system: "insufficient/inadequate/nondiagnostic"; "benign (negative for malignancy)," "atypical," "pancreaticobiliary neoplasm of low risk/low grade," "pancreatic neoplasm of high risk/high grade," "suspicious for malignancy," and "malignant." The principal differences between the WHO and the PSC systems revolve around the classification of neoplasia. In the PSC system, there was a single category for "neoplastic" lesions that includes two groups, one for "benign neoplasms" [primarily serous cystadenoma] and one named "other," dominated by premalignant intraductal neoplasms (primarily intraductal papillary mucinous neoplasms) and low-grade malignant neoplasms [pancreatic neuroendocrine tumors (PanNETs) and solid pseudopapillary neoplasms (SPNs)]. In the WHO system, benign neoplasms with virtually no risk of malignancy are included in the "benign" category and low-grade malignancies (PanNET and SPN) are included in the "malignant" category, as per the WHO Classification of Digestive System Tumours, thus leaving in the "neoplasm" category primarily those noninvasive premalignant lesions of the ductal system. These neoplasms are divided by the cytomorphological grade of the epithelium into low risk/low-grade and high risk/high-grade, with distinctly different risks of malignancy. As with the PSC system, the WHO system advocates close correlation with imaging and encourages incorporation of ancillary testing into the final diagnosis, such as biochemical (CEA and amylase) and molecular testing of cyst fluid and bile duct brushings. Key diagnostic cytopathological features of specific lesions or neoplasms, ancillary studies for diagnostic and prognostic evaluation, and implications of diagnosis for patient care and management are discussed. In addition, the WHO system includes reporting and diagnostic management options that recognize the variations in the availability of diagnostic and prognostic ancillary testing modalities in low- and middle-income countries, where cytopathology is particularly useful and is increasingly available in the absence of histopathological services.

Embedded Sensors for Structural Health Monitoring: Methodologies and Applications Review.

Sensing Technology (ST) plays a key role in Structural Health-Monitoring (SHM) systems. ST focuses on developing sensors, sensory systems, or smart materials that monitor a wide variety of materials' properties aiming to create smart structures and smart materials, using Embedded Sensors (ESs), and enabling continuous and permanent measurements of their structural integrity. The integration of ESs is limited to the processing technology used to embed the sensor due to its high-temperature sensitivity and the possibility of damage during its insertion into the structure. In addition, the technological process selection is dependent on the base material's composition, which comprises either metallic or composite parts. The selection of smart sensors or the technology underlying them is fundamental to the monitoring mode. This paper presents a critical review of the fundaments and applications of sensing technologies for SHM systems employing ESs, focusing on their actual developments and innovation, as well as analysing the challenges that these technologies present, in order to build a path that allows for a connected world through distributed measurement systems.

Whole human genome 5'-mC methylation analysis using long read nanopore sequencing.

Methylation microarray and bisulphite sequencing are often used to study 5'-methylcytosine (5'-mC) modification of CpG dinucleotides in the human genome. Although both technologies produce trustworthy results, the evaluation of the methylation status of CpG sites suffers from the potential side effects of DNA modification by bisulphite and/or the ambiguity of mapping short reads in repetitive and highly homologous genomic regions, respectively. Nanopore sequencing is an attractive alternative for the study of 5'-mC since it allows sequencing of native DNA molecules, whereas the long reads produced by this technology help to increase the resolution of those genomic regions. In this work, we show that nanopore sequencing with 10X coverage depth, using DNA from a human cell line, produces 5'-mC methylation frequencies consistent with those obtained by 450k microarray, digital restriction enzyme analysis of methylation, and reduced representation bisulphite sequencing. High correlation between methylation frequencies obtained by nanopore sequencing and the other methodologies was also noticeable in either low or high GC content regions, including CpG islands and transcription start sites. We also showed that a minimum of five reads per CpG yields strong correlations (>0.89) in replicate nanopore sequencing runs and an almost uniform linearity of the methylation frequency variation between zero and one. Furthermore, nanopore sequencing was able to correctly display methylation frequency patterns based on genomic annotations of CpG regions. These results demonstrate that nanopore sequencing is a fast, robust, and reliable approach to the study of 5'-mC in the human genome with low coverage depth.

Multisensor Inspection of Laser-Brazed Joints in the Automotive Industry.

Automobile laser brazing remains a complex process whose results are affected by several process variables that may result in nonacceptable welds. A multisensory customized inspection system is proposed, with two distinct non-destructive techniques: the potential drop method and eddy current testing. New probes were designed, simulated, produced, and experimentally validated in automobile's laser-brazed weld beads with artificially introduced defects. The numerical simulations allowed the development of a new four-point probe configuration in a non-conventional orthogonal shape demonstrating a superior performance in both simulation and experimental validation. The dedicated inspection system allowed the detection of porosities, cracks, and lack of bonding defects, demonstrating the redundancy and complementarity these two techniques provide.

Genomic data and multi-species demographic modelling uncover past hybridization between currently allopatric freshwater species.

Evidence for ancient interspecific gene flow through hybridization has been reported in many animal and plant taxa based on genetic markers. The study of genomic patterns of closely related species with allopatric distributions allows the assessment of the relative importance of vicariant isolating events and past gene flow. Here, we investigated the role of gene flow in the evolutionary history of four closely related freshwater fish species with currently allopatric distributions in western Iberian rivers-Squalius carolitertii, S. pyrenaicus, S. torgalensis and S. aradensis-using a population genomics dataset of 23,562 SNPs from 48 individuals, obtained through genotyping by sequencing (GBS). We uncovered a species tree with two well-differentiated clades: (i) S. carolitertii and S. pyrenaicus; and (ii) S. torgalensis and S. aradensis. By using D-statistics and demographic modelling based on the site frequency spectrum, comparing alternative demographic scenarios of hybrid origin, secondary contact and isolation, we found that the S. pyrenaicus North lineage is likely the result of an ancient hybridization event between S. carolitertii (contributing ~84%) and S. pyrenaicus South lineage (contributing ~16%), consistent with a hybrid speciation scenario. Furthermore, in the hybrid lineage, we identify outlier loci potentially affected by selection favouring genes from each parental lineage at different genomic regions. Our results suggest that ancient hybridization can affect speciation and that freshwater fish species currently in allopatry are useful to study these processes.

The benefits of the Papanicolaou Society of Cytopathology System for reporting pancreatobiliary cytology: A 2-year review from a single academic institution.

OBJECTIVE: Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) is an essential tool in the diagnosis of pancreatic lesions. The aim of this study was to evaluate the diagnostic accuracy of cytology from EUS-FNA, to correlate the results with the corresponding histopathological diagnoses and to analyse the impact of retrospective assignment of the Papanicolaou Society of Cytopathology (PSC) reporting system categories. METHODS: All pancreatic FNA specimens reported at the Royal Free Hospital during a 2-year period were retrospectively collected and assigned to the PSC system categories. Any available corresponding histological samples were assessed for concordance. RESULTS: In total, 236 cytology specimens from 223 patients were identified, of which 108 (45.8%) had corresponding histology samples. The main reason for cyto-histological discrepancy was sampling error. Interpretive error was identified in one case. Overall, sensitivity was 92.5%, specificity was 100%, diagnostic accuracy of cytology was 95%, false-positive rate was 0% and false-negative rate was 7.5%. The implementation of the new reporting system reduced the number of cases in the atypical category. All cases previously categorised as suspicious or malignant remained in the same category. CONCLUSIONS: EUS-FNA is an accurate method for evaluating pancreatobiliary lesions. The implementation of the Papanicolaou Society of Cytopathology diagnostic system enhances standardisation of the reporting terminology and reduces the number of samples in the non-standardised and equivocal atypical category.

Benchmarking of Nondestructive Testing for Additive Manufacturing.

Defect detection in additive manufacturing (AM) is of paramount importance to improve the reliability of products. Nondestructive testing is not yet widely used for defect detection. The main challenges are a lack of standards and methods, the types and location of defects, and the complex geometry of many parts. During selective laser melting (SLM), several types of defects can occur such as porosity, cracking, and lack of fusion. In this study, several nondestructive tests were conducted in a highly complex shaped part in AISI 316L stainless steel with real defects manufactured by SLM. Two additional artificial defects (one horizontal and one flat bottom hole) were produced and the defect detectability was evaluated. The techniques used were as follows: dye penetrant, infrared thermography, immersion ultrasonic, eddy current, and X-ray microcomputed tomography to assess different types of defects in the as-built part. We conclude that no single technique can detect every type of defect, although multiple techniques provide complementary and redundant information to critically evaluate the integrity of the parts. This approach is fundamental for improving the reliability of defect detection, which will help expand the potential for using AM to produce parts for critical structural applications.

A human factor event-based learning assessment tool for assessment of errors and diagnostic accuracy in histopathology and cytopathology.

This review article summarises systems for categorisation of diagnostic errors in pathology and cytology with regard to diagnostic accuracy and the published information on human factors (HFs) in pathology to date. A 12-point event-based checklist for errors of diagnostic accuracy in histopathology and cytopathology is proposed derived from Dupont's 'Dirty Dozen' HF checklist, as used in the aerospace industry for aircraft maintenance. This HF checklist comprises 12 HFs; (1) Failure of communication. (2) Complacency. (3) Lack of knowledge. (4) Distractions. (5) Lack of teamwork. (6) Fatigue. (7) Lack of resources. (8) Pressure. (9) Lack of assertiveness. (10) Stress. (11) Norms. (12) Lack of awareness. The accompanying article explains practical examples of how each of these 12 HFs may cause errors in diagnostic accuracy in pathology. This checklist could be used as a template for analysis of accuracy and risk of diagnostic error in pathology either retrospectively 'after the event' or prospectively at the time of diagnosis. There is a need for further evaluation and validation of this proposed 12-point HF checklist and similar systems for categorisation of diagnostic errors and diagnostic accuracy in pathology based on HF principles.