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Aims: This study aimed to assess the use of glucometers by patients and the analytical performance of glucometers provided by the primary care services. Methods: The analytical performance of 48 glucometers Accu-Chek® Active, was assessed through quintuplicate analyses of one Roche and one PNCQ (National Quality Control Program) control sample at different concentrations; 31 were also evaluated by a single proficiency testing sample. The evaluation metrics included imprecision, bias, and total error and were measured according to quality specifications based on biological variation (QSBV). Glucometer users answered a questionnaire regarding their experience. Results: Among the 48 glucometers evaluated with internal control samples, 17 met precision criteria at both control levels according to QSBV, while 24 met the criteria at only one control level. Of the 31 glucometers further evaluated through proficiency test, 11 met accuracy criteria according to QSBV, and only one device showed an unacceptable result. Out of these 31, only 15 demonstrated a total error within the acceptable maximum limits based on QSBV. Conclusions: Overall, our findings showed that patients had a good understanding of glucometer usage and suggested that some glucometers should be replaced, as they sometimes failed to meet even the manufacturer's acceptable variation limits, and/or did not meet QSBV.
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BACKGROUND AND OBJECTIVES: The storage temperature of immunohaematological reagents generally ranges from 2 to 8°C, and they should be utilised at room temperature. This study aimed to analyse the stability of immunohaematological reagents used in ABO and RhD typing. METHODS: The evaluation encompassed the potency, specificity, and integrity of anti-A, anti-B, anti-D, RhD control sera, and A1 and B red blood cells (RBC) reagents after long (8 h) and short (4 h) daily periods of exposure to room temperature (20-24°C), 5 days a week for 4 weeks. Additionally, the A1 and B RBC reagents were exposed daily for 11 h and 30 min at room temperature, including 30 more minutes at room temperature with simultaneous homogenisation through equipment. For the control, an aliquot of each reagent was constantly stored at refrigeration temperature, while another was exposed to room temperature for 12 h daily. Tests conducted included reaction intensity, titration, and avidity for antisera, reaction intensity, free haemoglobin determination, and electrical conductivity for the RBC reagents. RESULTS: The antisera maintained the reaction intensity. The titre and avidity of the antisera satisfied the minimum Brazilian requirements after different exposure periods. A higher free haemoglobin concentration was noted in the RBC reagents subjected to room temperature and simultaneous homogenisation, although this did not affect the potency and specificity. The electrical conductivity average of the RBC reagent remained consistent. CONCLUSION: The findings indicate that the immunohaematological reagents from a specific manufacturer are stable under the tested temperature, ensuring the quality of the results under these conditions.
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The use of probiotics brings numerous benefits to the immune system, including an increase in antibody production. The development of ABO antibodies may occur naturally due to the bacteria of the intestinal microbiota. However, high titers of ABO antibodies can lead to hemolytic disease of the fetus and newborn and can cause immune transfusion reactions. In this context, this study aimed to evaluate the effect of probiotic consumption on ABO antibody titers in humans. ABO blood group, ABO antibody titer, and fecal pH and Bifidobacteria concentration were determined for 126 healthy individuals before and after daily consumption of yogurt containing Lactobacillus acidophilus and Bifidobacterium lactis over a 1-month period. No changes in fecal pH were observed after probiotic consumption, regardless of ABO blood group. There was, however, an increase in the fecal concentration of Bifidobacteria in individuals with blood group A but not for those with group B or O. A decrease in the titer of anti-B was observed, despite the increase in the concentration of Bifidobacteria in feces being unrelated to fecal pH, in blood group A individuals. Our study, therefore, sought to understand the relationship between probiotics and the antibody titer of the ABO blood system. Despite our findings, further human studies are needed with other probiotic strains and molecular analyses of the intestinal microbiota.
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Sistema ABO de Grupos Sanguíneos , Probióticos , Bifidobacterium , Humanos , Recém-Nascido , Lactobacillus acidophilus , Iogurte/microbiologiaRESUMO
A rápida caracterização do genoma do Coronavírus-2 (SARS-CoV-2) mobilizou a produção em larga escala de métodos diagnósticos. Agências reguladoras aprovaram condicionalmente o uso emergencial de vários deles. Na emergência de saúde, inúmeros exames foram utilizados sem o devido conhecimento da qualidade. O objetivo desta revisão narrativa foi destacar a acurácia diagnóstica dos métodos sorológicos de diagnóstico da COVID-19 em termos de sensibilidade e especificidade clínicas. A sensibilidade diagnóstica variou até 50% entre estudos, enquanto a especificidade apresentou menor variação; no entanto, uma mesma marca chegou a apresentar variação de 32%. Considerando-se o critério de especificidade >95% definido pelo FDA, apenas uma marca de ensaio para detecção de IgG e outra para IgM atingiram a meta. Para a detecção de IgA e de IgA+IgM, as únicas marcas apresentadas não atingiram a meta. Entre as cinco marcas para detecção de IgM+IgG, apenas uma não atingiu a especificidade clínica. Para Ig total, as duas marcas apresentaram especificidade aceitável. Considerando-se o critério de sensibilidade clínica >90%, apenas 6 dos 25 estudos com diferentes marcas de ensaios para detecção de IgG apresentam o desempenho especificado; destas, nenhuma é brasileira. Nenhuma das marcas de ensaios para detecção de IgM e IgM+IgG apresentaram o desempenho especificado. A única marca apresentada para detecção de IgA+IgM atingiu a meta especificada pelo FDA. Os ensaios imunocromatográficos apresentaram menor sensibilidade. Os resultados demonstraram o pobre valor diagnóstico dos imunoensaios, mas com potencial para estudos soroepidemiológicos. Mais estudos de validação analítica e acurácia diagnóstica de ensaios são essenciais, principalmente dos reagentes nacionais.
The rapid characterization of the coronavirus-2 (SARS-CoV-2) genome has mobilized the large-scale production of diagnostic methods. Regulatory agencies have conditionally approved the emergency use of several of them. In the health emergency, numerous tests were used without proper knowledge of quality. The aim of this narrative review was to highlight the diagnostic accuracy of serological methods for the diagnosis of COVID-19 in terms of clinical sensitivity and specificity. The diagnostic sensitivity varied up to 50% between studies, while the specificity showed less variation, however, the same brand even showed a variation of 32%. Considering the >95% specificity criteria defined by the FDA, only one test brand for detection of IgG and one for IgM reached the goal. For the detection of IgA and IgA+IgM, the only brands presented did not reach the goal. Among the 5 marks for detecting IgM+IgG, only one did not reach clinical specificity. For total Ig, both brands had acceptable specificity. Considering the criterion of clinical sensitivity >90%, only 6 of the 25 studies with different brands of assays for detection of IgG present the specified performance, none of which are Brazilian. None of the brands of assays for detecting IgM and IgM+IgG showed the specified performance. The only brand presented for detection of IgA+IgM reached the target specified by the FDA. Immunochromatographic assays showed lower sensitivity. The results demonstrated the poor diagnostic value of immunoassays, but with potential for seroepidemiological studies. More studies on analytical validation and diagnostic accuracy of assays are essential, especially for national reagents.
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Imunoglobulina G , Imunoglobulina M , Testes Sorológicos , Confiabilidade dos Dados , SARS-CoV-2 , COVID-19/diagnósticoRESUMO
Devido à emergência do SARS-CoV-2, os laboratórios necessitaram se adequar na mes-ma velocidade em que a pandemia se instalou para atender com segurança à crescentedemanda pelos testes diagnósticos. Com o alto potencial de disseminação do vírus, o contato com pacientes e o manuseio laboratorial das amostras tornou-se um desafio sem precedentes para os laboratórios. A necessidade de práticas de biossegurança nunca foi globalmente tão enfatizada como nas circunstâncias atuais da pandemia. O objetivo desta revisão narrativa foi destacar medidas para prevenção da contaminação pelo SARS-CoV-2 nos laboratórios clínicos, utilizando como referência a literatura publicada em livros, artigos científicos, orientações técnicas de autoridades sanitárias e científicas, e na análise crítica e pessoal da autora. Alguns temas abordados foram: compreensão dos riscos, medidas de biossegurança, níveis de biossegurança, barreiras de contenção, uso correto dos equipamentos de proteção individual (EPI), desinfecção das áreas de laboratório, descarte seguro de resíduos, e biossegurança nas fases pré-analítica e analítica. As orientações são baseadas em evidências limitadas e frequentemente fracas, oriundas de opiniões, estudos observacionais ou extrapolações de epidemias anteriores causadas por outros coronavírus. As boas práticas de biossegurança destacadas foram estabelecidas muito antes do surgimento da COVID-19. No entanto, a pandemia trouxe à tona, aos profissionais de laboratório e à população em geral, boas práticas que estavam esquecidas, como a higienização das mãos, a etiqueta respiratória e a forma correta de paramentação e desparamentação dos EPI. Na pandemia, os laboratórios com poucos recursos necessitaram adaptar soluções seguras e econômicas para garantir a segurança laboral.
Due to the emergence of SARS-CoV-2 the laboratories had to adapt, as quickly as the pandemic was installed, to safely meet the growing demand for the diagnostic tests. The high potential for virus spread, contact with patients and laboratory handling of samples has become an unprecedented challenge for laboratories. The need for biosafety practices has never been more globally emphasized as in the current circumstances of the pandemic. The purpose of this narrative review was to highlight strategies to prevent contamination by SARS-CoV-2 in clinical laboratories, using as reference the literature published in books, scientific articles, technical guides from health and scientific authorities, and the critical and personal analysis of the author. Some topics that were covered: understanding risks, biosafety strategies, biosafety levels, containment barriers, correct use of personal protective equipment (PPE), disinfection of laboratory areas, safe disposal of waste, and biosafety in the pre-analytical and analytical phases.The orientations are based on limited and often weak evidence arising from opinions, observational studies or extrapolations from the previous epidemics coronaviruses. The highlighted good practices on biosafety were established long before the emergence of COVID-19. However, the pandemic brought up to the laboratory professionals and population in general, good practices that had been forgotten, such as hands hygiene, respiratory etiquette and the correct way of donning and doffing PPE. In the pandemic, laboratories with limited resources had to adapt safe and economical solutions to ensure safety in the clinical laboratory.
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Infecções por Coronavirus , Contenção de Riscos Biológicos , Pandemias , Equipamento de Proteção Individual , Betacoronavirus , LaboratóriosRESUMO
O diagnóstico da COVID-19 está alicerçado na clínica do paciente, nos exames de imagem e no diagnóstico laboratorial. O exame de detecção do ácido nucleico viral por transcrição reversa (RT) seguido da reação em cadeia da polimerase em tempo real (PCR) foi rapidamente o primeiro método de diagnóstico laboratorial estabelecido e permanece como o padrão ouro. Esta narrativa descritiva é resultado de uma busca referenciada onde o ponto focal foi descrever o diagnóstico laboratorial do SARS-CoV-2 por RT-PCR. O diagnóstico laboratorial do SARS-CoV-2 por RT-PCR envolve as etapas de extração do RNA, transcrição reversa para obtenção do DNA complementar e a reação em cadeia da polimerase. A detecção da amplificação do material genético é realizada pela medida de fluorescência emitida. Entre as várias amostras biológicas que podem ser utilizadas, aquela que tem apresentado mais praticidade e precisão é a de swab da nasofaringe. A coleta da amostra deve ser, idealmente, realizada até sete dias a partir do início dos sintomas. Quando o SARS-CoV-2 é detectado na RT-PCR, o diagnóstico de COVID-19 é confirmado. No entanto, um único resultado de SARS-CoV-2 não detectado em paciente sintomático não exclui o diagnóstico. O exame não tem apresentado reações cruzadas com outros patógenos respiratórios. Contudo, o exame é caro e demorado, e pode resultar em falso negativo devido ao momento inadequado da coleta da amostra, coleta e manuseio impróprio de amostras e material genético viral insuficiente no sítio de coleta. Lacunas diagnósticas ainda permanecem na triagem de assintomáticos e na detecção de vírus vivos na convalescença.
The diagnosis of COVID-19 is based on the patient's clinic, imaging tests and laboratory diagnosis. The detection of viral nucleic acid by reverse transcription (RT) followed by real-time polymerase chain reaction (PCR) was quickly the first established laboratory diagnosis method and remains the gold standard. This descriptive narrative is a result of a referenced search where the focal point was to describe the laboratory diagnosis of SARS-CoV-2 by RT-PCR. The laboratory diagnosis of SARS-CoV-2 by RT-PCR involves the RNA extraction, reverse transcription to obtain complementary DNA, and the polymerase chain reaction steps. The detection of genetic material amplification is carried out by measuring the emitted fluorescence. Among the various biological samples that can be used, the one that has shown the most practicality and precision is the nasopharyngeal swab. Sample collection should be performed, ideally, within 7 days from the symptoms onset. When SARS-CoV-2 is detected by RTPCR, the diagnosis of COVID-19 is confirmed. However, a single result of undetected SARS-CoV-2 in a symptomatic patient does not exclude the diagnosis. The test has not shown cross-reactions with common respiratory pathogens. However, the test is costly and timeconsuming, a false-negative result may arise due to inadequate sample collection time, improper samples collection and handling, and insufficient viral genetic material at the collection site. Diagnostic gaps remain on asymptomatic patients screening, and in the detection of live viruses in convalescence.
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Infecções por Coronavirus , Técnicas de Laboratório Clínico , Técnicas de Diagnóstico Molecular , Reação em Cadeia da Polimerase em Tempo Real , BetacoronavirusRESUMO
A atribuição do sistema sanguíneo ABO às infecções não é recente e não é exclusiva de infecções virais. A relação entre a COVID-19 e o grupo sanguíneo ABO de pacientes infectados tem sido investigada. O objetivo desta revisão foi avaliar se a associação do sistema sanguíneo ABO com SARS-CoV-2 envolve a isomeria ABO tecidual e subgrupos sanguíneos. Realizou-se uma revisão sistemática com busca de artigos e publicações até 28 de julho de 2020 na base PubMed. Foram obtidos 311 manuscritos dos quais 15 atenderam os critérios de inclusão e foram incluídos no estudo. Quarenta por cento dos estudos discutiram a possibilidade dos antígenos teciduais ABO influenciar na transmissão ou gravidade da COVID-19. Nenhum manuscrito mencionou que a isomeria antigênica ABO tecidual poderia predispor indivíduos às infecções por SARS-CoV-2 ou agravamento da COVID-19. Um manuscrito discutiu a possibilidade de o impedimento estérico afetar a saturação do receptor de diferentes isótipos de anticorpos anti-A1IgG em pacientes que desenvolveram COVID-19. Se rejeitássemos cartas e/ou comentários, análises profundas sobre o aspecto do sistema sanguíneo ABO e infecções por SARS-CoV-2 teriam sido excluídos e prejudicariam a discussão científica e as conclusões da revisão.
The assignment of the ABO blood system to infection is not new and is not exclusive to viral infections. The relationship between COVID-19 and the ABO blood group of infected patients has been investigated. The purpose of this review was to assess whether the association between ABO blood system and SARS-CoV-2 involves tissue ABO isomerism and blood subgroups. A systematic review was carried out with search until July 28, 2020 in PubMed database. Three hundred and eleven manuscripts were obtained, of which 15 met the inclusion criteria and were included in the study. Forty percent of the studies discussed the possibility of ABO tissue antigens influence the transmission or severity of COVID-19. No manuscript mentioned that ABO tissue antigenic isomerism could predispose individuals to SARSCoV-2 infections or severe COVID-19. A manuscript discussed the possibility of steric impediment affect receptorsaturation of the different antibodies A1IgG isotypes in COVID-19 patients. If the letters, correspondences or comments were rejected, deep analyzes of ABO blood system and SARS-CoV-2 infections relationship would have been excluded, and would undermine the scientific discussion and conclusions of the review.
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Sistema ABO de Grupos Sanguíneos , Infecções por Coronavirus , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave , BetacoronavirusRESUMO
INTRODUCTION: By quantifying the measurement uncertainty (MU), both the laboratory and the physician can have an objective estimate of the results' quality. There is significant flexibility on how to determine the MU in laboratory medicine and different approaches have been proposed by Nordtest, Eurolab and Cofrac to obtain the data and apply them in formulas. The purpose of this study is to compare three different top-down approaches for the estimation of the MU and to suggest which of these approaches could be the most suitable choice for routine use in clinical laboratories. MATERIALS AND METHODS: Imprecision and bias of the methods were considered as components of the MU. The bias was obtained from certified reference calibrators (CRC), proficiency tests (PT), and inter-laboratory internal quality control scheme (IQCS) programs. The bias uncertainty, the combined and the expanded uncertainty were estimated using the Nordtest, Eurolab and Cofrac approaches. RESULTS: Using different approaches, the expanded uncertainty estimates ranged from 18.9-40.4%, 18.2-22.8%, 9.3-20.9%, and 7.1-18.6% for cancer antigen (CA) 19-9, testosterone, alkaline phosphatase (ALP), and creatinine, respectively. Permissible values for MU and total error ranged from 16.0-46.1%, 13.1-21.6%, 10.7-26.2%, and 7.5-17.3%, respectively. CONCLUSION: The bias was highest using PT, followed by CRC and IQCS data, which were similar. The Cofrac approach showed the highest uncertainties, followed by Eurolab and Nordtest. However, the Eurolab approach requires additional measurements to obtain uncertainty data. In summary, the Nordtest approach using IQCS data was therefore found to be the most practical formula.