Assessment of misdiagnosis in small animal intensive care patients using the Modified Goldman criteria.

The postmortem examination can be used as a means of quality control for clinical diagnoses. A retrospective study on 300 dogs and cats that had been admitted to a small animal intensive care unit was performed comparing the clinical and postmortem findings, using the Modified Goldman criteria. All patient files were reevaluated for clinical diagnoses and all postmortem material was reevaluated for pathological diagnoses. After this, the Modified Goldman criteria were applied to score the discrepancies between them, and factors associated with the occurrence of an undiagnosed major unexpected finding were analyzed. The postmortem examination revealed additional findings in 65% of the cases. Major discrepancies, defined as those affecting treatment and possibly outcome of the patient, were present in 21.3% of the cases. The most frequently missed diagnoses detected at necropsy were pneumonia of various etiologies, meningitis/meningoencephalitis, myocarditis and generalized vasculitis. A shorter ICU stay was associated with increased odds of a major discrepancy. Conditions affecting the urinary or gastrointestinal system were negatively associated with major discrepancy.

Veterinary radiologic error rate as determined by necropsy.

A large-scale postmortem auditing of antemortem imaging diagnoses has yet to be accomplished in veterinary medicine. For this retrospective, observational, single-center, diagnostic accuracy study, necropsy reports for patients of The Schwarzman Animal Medical Center were collected over a 1-year period. Each necropsy diagnosis was determined to be either correctly diagnosed or discrepant with its corresponding antemortem diagnostic imaging, and discrepancies were categorized. The radiologic error rate was calculated to include only clinically significant missed diagnoses (lesion was not reported but was retrospectively visible on the image) and misinterpretations (lesion was noted but was incorrectly diagnosed). Nonerror discrepancies, such as temporal indeterminacy, microscopic limitations, sensitivity limitations, and study-type limitations were not included in the error rate. A total of 1099 necropsy diagnoses had corresponding antemortem imaging; 440 diagnoses were classified as major diagnoses, of which 176 were discrepant, for a major discrepancy rate of 40%, similar to reports in people. Seventeen major discrepancies were diagnoses that were missed or misinterpreted by the radiologist, for a calculated radiologic error rate of 4.6%, comparable with error rates of 3%-5% reported in people. From 2020 to 2021, nearly half of all clinically significant abnormalities noted at necropsy went undetected by antemortem imaging, though most discrepancies owed to factors other than radiologic error. Identifying common patterns of misdiagnosis and discrepancy will help radiologists refine their analysis of imaging studies to potentially reduce interpretive error.

Canine Ependymoma: Diagnostic Criteria and Common Pitfalls.

Reports of canine ependymoma are generally restricted to single case reports with tumor incidence estimated at 2% to 3% of primary central nervous system (CNS) tumors. While most commonly reported in the lateral ventricle, tumors can occur anywhere in the ventricular system and in extraventricular locations. Rosettes and pseudorosettes are a common histologic feature; however, these features can be mimicked by other CNS neoplasms. Thirty-seven potential ependymoma cases were identified in a retrospective database search of 8 institutions, and a histologic review of all cases was conducted. Of 37 cases, 22 candidate cases were further subjected to a consensus histologic and immunohistochemical review, and only 5 of 37 (13.5%) were conclusively identified as ependymoma. The neuroanatomic locations were the lateral ventricle (3/5), third ventricle (1/5), and mesencephalic aqueduct (1/5). Subtypes were papillary (4/5) and tanycytic (1/5). Histologic features included rosettes (5/5), pseudorosettes (5/5), ependymal canals (2/5), tanycytic differentiation (1/5), blepharoplasts (1/5), ciliated cells (1/5), and high nuclear to cytoplasmic ratio (5/5). Immunolabeling for GFAP (4/4) and CKAE1/3 (3/4) was found in pseudorosettes, rosettes, and scattered individual neoplastic cells. Diffuse but variably intense cytoplasmic S100 immunolabeling was detected in 3 of 4 cases. Olig2 intranuclear immunolabeling was observed in less than 1% of the neoplastic cells (3/3). Tumors that had pseudorosettes and mimicked ependymoma included oligodendroglioma, choroid plexus tumor, pituitary corticotroph adenoma, papillary meningioma, and suprasellar germ cell tumor. These findings indicate that canine ependymoma is an extremely rare neoplasm with histomorphologic features that overlap with other primary CNS neoplasms.

Reporting results with (Un)certainty.

BACKGROUND: A degree of uncertainty occurs with every measured laboratory result due to both analytical and biological variation. The tools of Total Observed error (TEO ) and dispersion based on biological variation have helped veterinary labs quantify the causes of variation that lead to measurement uncertainty (MU). International organizations recommend that the amount of MU in veterinary laboratory results be identified and communicated. The expanded measurement uncertainty (EMU), dispersion, and reporting interval adjustment have been recommended as tools to allow communication of MU to laboratory data users but are not commonly discussed in the veterinary literature. OBJECTIVE: Using the vocabulary of Total Observed error and biological variation and examples from veterinary medicine, a review of the theory and application of the EMU, dispersion, and the methods for deriving an appropriate reporting interval recommended by Hawkins and Badrick, is presented. CONCLUSIONS: By addressing the way that MU is communicated to users of laboratory results, the laboratory enables users to better understand the potential uncertainty associated with reported results, helps to prevent over and under-interpretation of data, and improves diagnostic accuracy and patient care.

A Case of Animal and Domestic Abuse Initially Diagnosed as Legg-Calve-Perthes Disease.

A 1 yr old castrated male shih tzu was evaluated for an acute right rear limb lameness and hyphema in the anterior chamber of the right eye. On initial examination, the dog was non-weight bearing on his right rear limb. Ophthalmic examination revealed a centrally located, superficial corneal ulcer in the right eye and blood in the anterior chamber. Radiographic findings of the pelvis and right rear were suggestive of avascular necrosis of the right femoral neck with resultant fracture and possible avascular necrosis of the left femoral neck. The dog presented 20 days later for evaluation of an acute left rear limb lameness. A left distal femur Salter-Harris type II fracture; a nondisplaced, healing right pubic fracture; and a healing right zygomatic arch transverse fracture were seen on radiographs. The dog's initial injuries were attributed to a routine fall at home, and radiographic interpretation suggested that this was plausible. Subsequent patient visits, evaluation of additional injuries, and interviews with the owner indicated that both animal and domestic abuse had occurred. Veterinarians must be alert to recognize signs of animal abuse and must be aware of the connection between animal and domestic abuse.

Iridociliary cysts masquerading as neoplasia in cats: a morphologic review of 14 cases.

OBJECTIVE: To report 14 neoplasia-free feline eyes enucleated for suspected intraocular neoplasia containing only iridociliary cysts. To analyze clinical findings that may have led veterinarians to suspect neoplasia in these globes. PROCEDURES: The archives at the Comparative Ocular Pathology Laboratory of Wisconsin (COPLOW) were searched to identify neoplasia-free feline globes enucleated for suspected neoplasia. Clinical data were obtained from medical records, veterinarian surveys, and COPLOW submission forms. All samples were examined grossly and histologically. RESULTS: All eyes were free of neoplasia and contained one or more iridociliary cysts. Nine of 14 globes were enucleated by or based on the recommendation of a board-certified veterinary ophthalmologist. In eight of 14 cases, the submitting clinician listed melanoma as the only suspected diagnosis; in six of 14 cases, 'tumor' or 'mass' was listed. Clinical examination revealed a darkly pigmented intraocular mass in 11 of 14 cases. The mass was clinically perceived to be within the iris in seven of 14 cases. When examined histologically, 11 of 14 eyes contained multiple cysts, 13 of 14 contained multiloculated cysts, eight of 14 had a hyperplastic iris pigmented epithelium or cysts with thick black walls, and five of 14 had cysts prolapsed into the anterior chamber. CONCLUSIONS: Although most iridociliary cysts in cats are easily diagnosed on clinical examination, a subset may be mistaken for neoplasia. In cases of suspected iris melanoma, iridociliary cysts should be considered as a differential diagnosis, especially if a mass appears to emanate from behind the iris, dyscoria is present, or if similar changes are noted in the contralateral eye.

Angiostrongylus vasorum infection in dogs from a cardiopulmonary dirofilariosis endemic area of Northwestern Italy: a case study and a retrospective data analysis.

BACKGROUND: In Italy, Angiostrongylus vasorum, an emergent parasite, is being diagnosed in dogs from areas considered free of infection so far. As clinical signs are multiple and common to other diseases, its diagnosis can be challenging. In particular, in areas where angiostrongylosis and dirofilariosis overlap, a misleading diagnosis of cardiopulmonary dirofilariosis might occur even on the basis of possible misleading outcomes from diagnostic kits. CASE PRESENTATION: Two Cavalier King Charles spaniel dogs from an Italian breeding in the Northwest were referred to a private veterinary hospital with respiratory signs. A cardiopulmonary dirofilariosis was diagnosed and the dogs treated with ivermectin, but one of them died. At necropsy, pulmonary oedema, enlargement of tracheo-bronchial lymphnodes and of cardiac right side were detected. Within the right ventricle lumen, adults of A. vasorum were found. All dogs from the same kennel were subjected to faecal examination by FLOTAC and Baermann's techniques to detect A. vasorum first stage larvae; blood analysis by Knott's for Dirofilaria immitis microfilariae, and antigenic tests for both A. vasorum (Angio Detect™) and D.immitis (DiroCHEK® Heartworm, Witness®Dirofilaria). The surviving dog with respiratory signs resulted positive for A. vasorum both at serum antigens and larval detection. Its Witness® test was low positive similarly to other four dogs from the same kennel, but false positive results due to cross reactions with A. vasorum were also considered. No dogs were found infected by A. vasorum. Eventually, the investigation was deepened by browsing the pathological database of Veterinary Pathology Laboratories at Veterinary School of Milan University through 1998-2016, where 11 cases of angiostrongylosis were described. Two out of 11 dogs had a mixed infection with Crenosoma vulpis. CONCLUSION: The study demonstrates the need for accurate surveys to acquire proper epidemiological data on A. vasorum infection in Northwestern Italy and for appropriate diagnostic methods. Veterinary clinicians should be warned about the occurrence of this canine parasite and the connected risk of a misleading diagnosis, particularly in areas endemic for cardiopulmonary dirofilariosis.

Analytic and quality control validation and assessment of field performance of a point-of-care chemistry analyzer for use in the White rhinoceros.

BACKGROUND: A chemistry point-of-care analyzer would be useful for evaluating injured wildlife, particularly White rhinoceros (Ceratotherium simum) that survive poaching attempts. The IDEXX VetTest could be suitable, but species-specific validation, development of a statistical quality control (QC) strategy, and evaluation under field conditions are necessary. OBJECTIVES: The objectives were to (1) validate the VetTest for the White rhinoceros, (2) perform QC validation on the VetTest and generate a statistical QC strategy, and (3) apply this QC strategy to monitor performance under typical field conditions. METHODS: Differences between White rhinoceros heparin plasma and serum, short-term imprecision, and reportable range using rhinoceros plasma and long-term imprecision using commercial quality control material (QCM) were assessed against prescribed total allowable error (TEa ) for up to 15 analytes. Quality control validation was performed using data from the long-term imprecision study and TEa . A QC strategy using QCM was developed and used to monitor performance under field conditions. RESULTS: Imprecision was acceptable for all analytes except for ALP, ALT, and AST at low activities. The reportable range for AST and LDH differed from the manufacturer's specifications. Eleven analytes were suitable for statistical QC using the 13s rule, 3 using the 2s rule; ALP was not suitable. In the field, observed error was < TEa for all 15 analytes and the sigma metric was > 3.0 for 12 analytes. CONCLUSIONS: The VetTest is suitable for use in the White rhinoceros. Statistical QC is possible for most analytes and useful for evaluation of field performance.

Accuracy of Ultrasonographic Measurements of Adrenal Glands in Dogs: Comparison with Necroscopic Findings.

Ultrasonographic evaluation of the adrenal glands was performed in 85 dogs, followed by macroscopic and histopathological examination either post-mortem or after adrenalectomy. This retrospective cross-sectional study evaluated the difference between gross and ultrasonographic measurements to determine the diagnostic accuracy of ultrasonography in the evaluation of canine adrenal gland size. The differences were assessed for gland length, thickness at cranial, middle and caudal regions, and surface area. In our sample, ultrasound error accuracy ranged between 0% in measurement of the right adrenal gland surface area and 25.21% for left cranial pole thickness. The parameters with minor errors were caudal pole thickness (3.64% right side and 3.49% left side) and length (5.75% right side and 2.19% left side). The ultrasonographic measurements generally underestimated the actual size of the adrenal glands. No statistically significant differences were observed for measurement errors between normal and pathological adrenal glands. This study confirmed that the caudal pole of both glands is the best parameter for ultrasonographic evaluation of normal and pathological adrenal glands size in dog. Furthermore, the surface area could be considered as a dimensional parameter for better assessment of the complex shape and the global aspect of the adrenal glands, while standardize ultrasonographic projections are needed to measure the cranial pole of both adrenal glands.

Optimizing Feedlot Diagnostic Testing Strategies Using Test Characteristics, Disease Prevalence, and Relative Costs of Misdiagnosis.

Diagnostic tests are commonly used by feedlot practitioners and range from clinical observations to more advanced physiologic testing. Diagnostic sensitivity and specificity, estimated prevalence in the population, and the costs of misdiagnoses need to be considered when selecting a diagnostic test strategy and interpreting results. This article describes methods for evaluating diagnostic strategies using economic outcomes to evaluate the most appropriate strategy for the expected situation. The diagnostic sensitivity and specificity, and expected prevalence influence the likelihood of misdiagnosis in a given population, and the estimated direct economic impact can be used to quantify differences among diagnostic strategies.

Morphology and immunophenotype of canine cutaneous histiocytic tumours with particular emphasis on diagnostic application.

This study evaluated the morphology and immunohistochemistry of 85 canine cutaneous histiocytic tumours. The tumours were classified morphologically as either canine cutaneous histiocytomas (71 tumours) or canine cutaneous histiocytic sarcomas (14 tumours). The immunohistochemical analysis was conducted on paraffin sections using an antibody panel (against MHCII, CD18, CD79αcy, CD3 and E-cadherin). Histochemical staining with toluidine blue and Gomori silver impregnation was also performed. A follow-up was conducted via surveys. The histiocytic origin of the tumour cells was confirmed in 65 of the canine cutaneous histiocytomas and in 4 of the canine cutaneous histiocytic sarcomas. The tumours that had been misdiagnosed as canine cutaneous histiocytomas included plasmacytomas, epitheliotropic T-cell lymphomas and undetermined entities. The tumours misdiagnosed as canine cutaneous histiocytic sarcomas included plasmacytomas and non-epitheliotropic T-cell lymphomas, but the majority of them remained undetermined. The canine cutaneous histiocytomas showed MHCII, CD18 and E-cadherin expression, but in several of the tumours, the expression of CD18 or E-cadherin was confirmed in only a small percentage of the tumour cells. The regressing canine cutaneous histiocytomas showed increased T- and B-lymphocyte infiltration, a decreased mitotic index, transport of the MHCII molecules from the cytoplasm to the cell membrane and loss of E-cadherin expression in the tumour cells. The canine cutaneous histiocytic sarcomas showed both high morphological diversity and expression of MHCII and CD18. Two of the evaluated histiocytic sarcomas also showed expression of E-cadherin. In conclusion, immunohistochemistry, including analysis of MHCII, CD18 and the lymphocytic markers CD3 and CD79, should be performed for the diagnosis of canine cutaneous histiocytic tumours. The expression of E-cadherin in canine cutaneous histiocytic sarcomas suggests an origin of the tumour cells among Langerhans cells.

The elephant in the room (and how to lead it out): In-clinic laboratory quality challenges.

Over 30 yr of technological evolution have resulted in sophisticated instrumentation for in-clinic laboratories, yet there is no regulatory oversight of diagnostic testing quality. Long overdue, the veterinary profession must address quality assurance (QA) of diagnostic testing. Each practice must weigh the responsibility for laboratory instrumentation test results that are often a combination of in-clinic and send-out testing. Challenges faced by clinic staff maintaining in-clinic laboratories include lack of training in QA and quality control (QC), lack of emphasis placed on QA/QC by instrument suppliers, QC financial and time costs, and a general lack of laboratory QA/QC support resources in the veterinary community. Possible solutions include increased continuing education opportunities and the provision of guidelines and other resources by national veterinary organizations; specialty certification of veterinary technicians; an increasing role of veterinary clinical pathologists as QA/QC consultants; and development of external quality assessment programs aimed at veterinary practices. The potential exists for animal health companies to lead in this effort by innovating instrument design, providing QC services, and exploiting instrument connectivity to monitor performance. Veterinary laboratory QA/QC is a neglected aspect of the profession. In coming years, veterinarians will hopefully find increased support for this core practice component.

Survey of point-of-care instrumentation, analysis, and quality assurance in veterinary practice.

BACKGROUND: While there have been ASVCP meeting discussions regarding quality assurance plans and lack thereof for in-clinic analyzers, there are little published data regarding in-clinic quality assurance and control practices. OBJECTIVES: The purpose of this study was the identification of the common equipment used in hematologic, biochemical, urinalysis, and other testing, and assessment of quality control and assurance programs currently being performed in-clinic. METHODS: All members of the Veterinary Information Network (VIN) were solicited to participate in an online survey between July and September 2007. RESULTS: In total, 452 complete or partial responses were received. Eighty-nine percent of respondents (361/404) said that veterinary technicians (unlicensed, licensed, and registered) performed the majority of analyses. Eighty-eight percent (366/417) of respondents performed some quality assurance on their laboratory equipment, most commonly on chemistry (91%, 324/357), and hematology (84%, 292/347) analyzers, and least commonly on fecal analyses (57%, 148/260) and ELISA assays (25%, 65/256). Ignorance of how to perform quality assurance was the most commonly stated reason (49%, 25/51) for lack of a quality assurance program. The majority of practices (316/374) utilized manufacturer-provided reference intervals without further adjustment or assessment. Roughly one-third of respondents (126/374) used reference intervals from textbooks, which is discouraged by ASVCP guidelines. CONCLUSIONS: This study found that the majority of respondents were not in compliance with ASVCP guidelines, illustrating the need for improved education of technical staff, veterinary students, and veterinarians regarding limitations of in-clinic laboratory equipment and the importance of regular quality control, maintenance, training, and reference interval development.

Analytical performance of a dry chemistry analyzer designed for in-clinic use.

BACKGROUND: The Heska Dri-Chem 4000 uses dry slide technology to evaluate serum or plasma. No previous independent performance evaluation is published to the authors' knowledge. OBJECTIVES: The objectives were to (1) characterize analytical performance of a Dri-Chem 4000 by measuring precision and bias, (2) compare analytical performance of that Dri-Chem 4000 unit with a predetermined quality requirement, and (3) determine whether statistical QC of the Dri-Chem 4000 is possible using the 13s control rule. METHODS: Sixteen analytes were measured using plasma from dogs, cats, and horses. Coefficient of variation (CV), bias, and observed total error (TEobs ) were calculated. TEobs was compared with allowable total error (TEa ). Sigma metric and quality goal index were calculated where relevant. QC validation was performed. RESULTS: Bias and TEobs calculated using quality control material (QCM) data were smaller than those calculated using method comparison data. Using TEobs calculated from species-specific CV and QCM-based bias, 100% of analytes in each species met ASVCP-recommended TEa . Desired error detection and false rejection rates were achievable using the 13s control rule and ASVCP-recommended TEa values for 9/16 (56%) of analytes in dogs, 9/14 (64%) of analytes in cats, and 8/13 (62%) of analytes in horses. CONCLUSIONS: Analytical performance of the Dri-Chem 4000 is comparable to that reported by other authors for other small benchtop biochemistry analyzers. Statistical QC using a simple control rule is possible for most analytes in dogs, cats, and horses.

Trichinella detection: identification and statistical evaluation of sources of error in the magnetic stirrer method for pooled sample digestion.

Proficiency testing (PT) is the use of inter-laboratory comparisons to determine the performance of individual laboratories for specific tests or measurements, and to monitor a laboratory's performance. Participation in proficiency testing provides laboratories with an objective means of assessing and demonstrating the reliability of the data they are producing. To ensure the reliability of Trichinella detection and meat hygiene within the European Union and afford optimal protection to the consumer, PT is conducted under the direction of the European National Reference Laboratories for Trichinella. Evaluation of data from the national PT showed that lab-internal shortcomings are frequent. These shortcomings are specifically related to: (1) improper sample collection and preparation; (2) incorrect transposition and application of the protocol as laid down in Annex I, Chapter I, Nr. 3 (a-g) of the Commission Regulation (EC) No. 2075/2005; (3) insufficient sedimentation times; and (4) improper equipment.(e.g. Prost and Nowakowski, 1990; Rossi and Pozio, 2008; Forbes and Gajadhar, 1999; Rossi and Pozio, 2008). To test the hypothesis that both method based errors as well as internal lab errors can influence the accuracy and precision of the magnetic stirrer method for pooled sample digestion (MSM), we initiated a study to evaluate the analytical uncertainty of the MSM. Results presented here are based on: (i) data from PT in Germany (2008, 2009, and 2010); (ii) within-lab performance conducting high volumes of MSM; (iii) larval recovery experiments; and (iv) statistical evaluation of data resulting from these procedures. Quantitative data from the PT show that on average only 60% of Trichinella larvae were detected. Even laboratories that showed relatively good performance (>80% larva recovery, no false negative or false positive results), frequently reported samples with an unexpectedly low larval count (loss of >2 larvae). In our own laboratory, high numbers of repeated analyses of standards and re-analyses of residual fluids indicated that these outliers could be described by a binomial distribution based on a laboratory-specific Trichinella-detection probability. Results of recovery experiments indicate that only a part of the total larval losses can be attributed to lab-internal shortcomings inasmuch as a significant number of L1 could be isolated from the residual and washing fluids.

A multidisciplinary approach to diagnose naturally occurring bovine tuberculosis in Brazil / Uma abordagem multidisciplinar para o diagnóstico de tuberculose bovina em um rebanho naturalmente infectado no Brasil

A herd infected naturally with tuberculosis was investigated by different diagnostic methods. Ninety days after a screening test that identified 21 cows as skin test positive, a Comparative Intradermal Tuberculin Test (CITT) was performed in those 21 cows and in 29 other randomly selected skin test negative cows. Milk samples and nasal swabs were collected prior to the CITT for bacteriological culture and PCR, while blood samples were collected for IFN release and antibody responses to MPB70 and MPB83, at three time points post tuberculin injection. Animals positive by CITT were slaughtered and disease confirmation undertaken. Based on the Kappa test, IFN was comparable to the standard tests (culture, PCR and CITT) at all three sampling points. Results from both antibody ELISAs were similar but were not comparable to the standard tests. T-test analysis of the CITT, IFN and ELISAs demonstrated that their performances were not correlated. There is increasing recognition that individually, available diagnostic tests do not detect all infected cattle. Therefore, a comprehensive strategy for the diagnosis of bovine TB should include test results for the detection of both cellular and humoral immune responses where there may be animals at different stages of infection.

Um rebanho bovino naturalmente infectado por tuberculose foi analisado através de diferentes métodos diagnósticos. Um teste intradérmico simples (TIC) identificou 21 animais como positivos. Após 90 dias deste resultado, um teste intradérmico comparativo (TIC) foi aplicado nos 21 animais positivos ao TIS, além de outros 29 animais com resultados prévios negativos escolhidos aleatoriamente. De todos estes animais (50), foram coletadas amostras de leite e secreção nasal para isolamento e identificação de microrganismos por cultura e PCR; amostras de sangue de cada um dos animais foram coletadas para exames de ELISA: produção de Interferon-gama (IFN) e pesquisa de anticorpos frente aos antígenos MPB70 e MPB83. Tais amostras sanguíneas foram coletadas em três diferentes momentos: no dia da execução do TIC e nos dias dia 7 e dia 21 após a execução do TIC. Os animais que foram positivos a este teste foram abatidos; exames de identificação do agente, tais como cultivo e PCR foram realizados post-mortem para confirmação da doença. Baseado na análise Kappa, IFN apresentou resultados estatisticamente comparáveis aos resultados de isolamento e identificação bacteriana por cultura e PCR, além do TIC ao longo de todo o experimento. No entanto, TIC, ELISA e IFN não foram estatisticamente comparáveis. Tais resultados sugeriram que nenhum dos atuais métodos de diagnóstico para tuberculose possibilitou a identificação de todos os animais infectados. Por este motivo, uma estratégia mais abrangente deveria incluir métodos de diagnóstico que pudessem identificar a resposta imune celular e humoral, uma vez que animais de um mesmo rebanho poderiam se encontrar em diferentes estágios da infecção.