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Reference materials (RM) are tools used in the comparability and traceability of measurements. They are widely used by laboratories for method validation and quality control of assay. Chile must evaluate theperformance of laboratories that analyzing metals in fishery products, despite RM have high prices and are scarce. For that reason, a RM in a hydrobiological product was developed. Reference values for arsenic and cadmium elements for a fishmeal were assigned. The measurement methods for characterization of the material were Inductively Coupled Plasma Mass Spectrometry, Atomic Absorption Spectrometry and Neutron Activation Analysis. Reference values with their expanded uncertainty (U) were established for arsenic 2.64 ± 0.42 mg/kg (U; k = 2) and for cadmium 0.86 ± 0.16 mg/kg (U; k = 2). Homogeneity and stability of the RM allowed its use in a proficiency test for eleven food control laboratories. Results for median were 2.114 mg/kg for arsenic, and 0.863 mg/kg for cadmium. The performance values of the participants were evaluated with a z score obtaining 60% satisfaction for arsenic and 73% for cadmium.The material demonstrated to be suitable for use in interlaboratory proficiency assay. (AU)

Materiales de referencia (MR) son herramientas utilizadas en la comparabilidad y trazabilidad entre mediciones. Laboratorios los utilizan ampliamente en validación de métodos y control de calidad. Chile debe evaluar el desempeño de los laboratorios que analizan metales en productos pesqueros, a pesar de los altos precios y escasez del MR. Por esa razón, se desarrolló un MR en producto hidrobiológico. Se asignaron valores de referencia para arsénico y cadmio en harina de pescado. Los métodos de medición para la caracterización del material fueron Espectrometría de Masas de Plasma Acoplado Inductivamente, Espectrometría de Absorción Atómica y Análisis de Activación de Neutrones. Se establecieron valores de referencia con su incertidumbre (U) para arsénico 2.64 ± 0.42 mg/kg (U; k = 2) y para cadmio 0.86 ± 0.16 mg/kg (U; k = 2). La homogeneidad y estabilidad del MR permitieron su uso en una prueba de aptitud para once laboratorios de control de alimentos. Las medianas fueron 2,114 mg/kg para arsénico y 0,863 mg/kg para cadmio. Se evaluaron los rendimientos de los participantes con un estadístico de puntaje z satisfactorio del 60% para el arsénico y 73% para el cadmio. El material demostró ser adecuado para uso en ensayo de aptitud de intercomparación. (AU)

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Histamine determination is relevant for fish safety, quality and trade. Recently a study by the European Union (EU) compared the Codex and the EU mandated methods for the analysis of histamine and observed that they underestimated and overestimated the results, respectively. To solve this problem, a simple and efficient procedure for the extraction and quantification of histamine by ion-pair HPLC method with post-column derivatization and fluorimetric detection is proposed. It was optimized and validated for the analysis of histamine in fish. The method attended the performance criteria established by Commission Decision 2002/657/CE. The method was also submitted to proficiency testing; uncertainty was calculated; and the stability of solutions and standards was investigated. There was no matrix effect. The LOD, LOQ, CCα and CCß were fit for the purpose. The method was successfully used in the analyses of freshwater fish and fresh and canned tuna.

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Bee products can be produced in an environment contaminated by pesticides that can be transported by honey bees to the hive and incorporated into the honey. Therefore, rapid and modern methods to determine pesticide residues in honey samples are essential to guarantee consumers' health. In this study, a simple multiresidue method for the quantification of 116 pesticides in honey is proposed. It involves the use of a modified QuEChERS procedure followed by UHPLC-MS/MS analysis. The method was validated according to the European Union SANCO/12571/2013 guidelines. Acceptable values were obtained for the following parameters: linearity, limit of detection (0.005mg/kg) and limit of quantification (0.010 and 0.025mg/kg), trueness (for the four tested levels the recovery assays values were between 70 and 120%), intermediate precision (RSD<20.0%) and measurement uncertainty tests (<50.0%). The validated method was applied for determination of 100 honey samples from five states of Brazil.

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BACKGROUND: Since the re-emergence of Chikungunya virus (CHIKV) in Reunion in 2005 and the recent outbreak in the Caribbean islands with an expansion to the Americas the CHIK diagnostic became very important. OBJECTIVES: We evaluate the performance of laboratories regarding molecular and serological diagnostic of CHIK worldwide. STUDY DESIGN: A panel of 12 samples for molecular and 13 samples for serology were provided to 60 laboratories in 40 countries for evaluating the sensitivity and specificity of molecular and serology testing. RESULTS: The panel for molecular diagnostic testing was analysed by 56 laboratories returning 60 data sets of results whereas the 56 and 60 data sets were returned for IgG and IgM diagnostic from the participating laboratories. Twenty-three from 60 data sets performed optimal, 7 acceptable and 30 sets of results require improvement. From 50 data sets only one laboratory shows an optimal performance for IgM detection, followed by 9 data sets with acceptable and the rest need for improvement. From 46 IgG serology data sets 20 provide an optimal, 2 an acceptable and 24 require improvement performance. The evaluation of some of the diagnostic performances allows linking the quality of results to the in-house methods or commercial assays used. CONCLUSION: The external quality assurance for CHIK diagnostics provides a good overview on the laboratory performance regarding sensitivity and specificity for the molecular and serology diagnostic required for the quick and reliable analysis of suspected CHIK patients. Nearly half of the laboratories have to improve their diagnostic profile to achieve a better performance.

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OBJETIVO: Avaliar o desempenho dos calibradores de radionuclídeos de 55 serviços de medicina nuclear brasileiros em medição de atividade de radiofármaco contendo 99Tc m. Testes de proficiência foram aplicados em 63 resultados originados do programa de comparação promovido pelo Laboratório Nacional de Metrologia das Radiações Ionizantes do Instituto de Radioproteção e Dosimetria. MATERIAIS E MÉTODOS: O desempenho foi avaliado em relação ao critério de aceitação de ±10 por cento de exatidão exigido pela norma brasileira e também aos critérios estabelecidos pela ISO/IEC Guide 43-1, e classificado como "aceitável" ou "não aceitável". Amostras de 99Tc m usadas nas comparações foram fornecidas por alguns dos participantes e calibradas no Laboratório Nacional de Metrologia das Radiações Ionizantes para determinar o valor de referência da atividade. RESULTADOS: Esta comparação com o 99Tc m mostrou que o desempenho aceitável atendendo à exigência da norma regulatória foi de 82,5 por cento, enquanto pelos critérios estabelecidos pela norma ISO/IEC 43-1 foi de 81,0 por cento. Por outro lado, calibradores de radionuclídeos com detector Geiger-Müller apresentaram desempenho inferior quando comparados com os dotados com câmara de ionização. CONCLU-SÃO: Nesta comparação, a avaliação do desempenho baseada nos critérios da ISO/IEC 43-1, os quais são aplicados a laboratórios analíticos, apesar de serem mais restritivas, foi bastante consistente com o critério de exatidão exigido pela norma nacional.

OBJECTIVE: To assess the performance of radionuclide calibrators in 55 Brazilian nuclear medicine services in the measurement of 99Tc m radiopharmaceutical activity. Proficiency tests were applied to data sets with 63 results originated from the comparison program developed by Laboratório Nacional de Metrologia das Radiações Ionizantes of Instituto de Radioproteção e Dosimetria. MATERIALS AND METHODS: The calibrators' performance was evaluated in compliance with the acceptance criterion of ±10 percent accuracy required by the Brazilian standards and also the criteria established by the ISO/IEC Guide 43-1, and classified as either "acceptable" or "non-acceptable". The samples of 99Tc m utilized in the comparison were supplied by some of the participants and calibrated at Laboratório Nacional de Metrologia das Radiações Ionizantes for determining the activity reference value. RESULTS: The present study utilizing 99Tc m has shown that 82.5 percent of the calibrators were considered as acceptable according to the Brazilian standards, while by the criteria established by ISO/IEC 43-1, 81.0 percent were considered as acceptable. On the other hand, radionuclide calibrators with Geiger-Müller detectors presented unsatisfactory performance when compared with calibrators with ionization chambers. CONCLUSION: The performance evaluation based on the ISO/IEC 43-1 criteria, which are applied to analytical laboratories, in spite of being more restrictive, has demonstrated to be quite consistent with the accuracy criterion established by the Brazilian standard.

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A identificação de variáveis que influenciam a proficiência em Língua Portuguesa é essencial para a elaboração de intervenções que visam melhorar o desempenho acadêmico dos alunos. Para tanto, os dados de 33.962 alunos da 3ª série de 1.661 escolas de Ensino Médio que fizeram o teste de Língua Portuguesa aplicado pelo SAEB em 2001 foram analisados utilizando análise multinível. Os resultados mostram que, depois do controle das variáveis relacionadas com a composição e seletividade da escola, o efeito escola está variando entre as regiões brasileiras de 0,10 para o Sul a 0,13 para o Norte. Estes valores indicam que mesmo depois da inserção das variáveis de controle, o conjunto de fatores escolares pode explicar entre 10 por cento e 13 por cento da variabilidade total do desempenho em português. As análises permitiram a identificação de três variáveis no nível da escola e dez variáveis no nível do aluno associados ao desempenho em Língua Portuguesa.(AU)

The identification of variables that affect proficiency in Portuguese Language is essential for the elaboration of interventions that seek to improve student achievement in Brazil. To achieve this goal, we analyzed the data of 33,962 third grade students of 1,661 secondary schools who took the Portuguese Language test of the National Basic Education System of Evaluation of Basic Education (SAEB) in 2001 using multilevel analysis. The results of this study showed that, after controlling the effect of variables related to the composition and selectivity of the schools, the intraclass correlation varied among the Brazilian regions between 0.10 for the South and 0.13 for the North. These figures indicate that even after the insertion of the control variables, school factors can explain between 10 percent and 13 percent of the total variability in Portuguese performance. Three variables on school level and ten variables on student level were identified as affecting proficiency in Portuguese Language.(AU)

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The participation in Interlaboratory Comparison Programme (IP) is a tool used by laboratories to ensure reliability of analytical results. In IPs the selection of a statistical treatment applied to the results can affect the estimation of the true value (assigned value) and its uncertainty, the acceptance range and the performance assessment of the participants laboratories. Using the results of the participant laboratories in the Proficiency Test Programme for lead in blood, coordinated by Instituto Adolfo Lutz, São Paulo, for different levels of concentration, seven statistical techniques were compared. The assigned value was calculated using the median, or the average value after the elimination of the dispersed results, employing Hampel, Grubbs, Dixon and Z-scores criteria. The acceptance range was calculated according to Z score,making use of the standard deviation or using Horwitzs equation or the Horwitzs one modified by Thompson. It was also used the current criterion applied to the Program, which considers Xdesignated ± 6, for concentrations [Pb-s] 40 g/100mL and Xdesignated ± 15% Xdesignated for concentrations > 40 g/ 100mL. It was verified that the assigned values obtained through the statistical techniques used did not present significant differences when the confidence level was 5%. However, the acceptance ranges obtained showed they were influenced by t

A participação em Programas de comparação Interlaboratorial (PI) é uma ferramenta utilizada pelos laboratórios para garantir a confiabilidade de seus resultados analíticos. Em PIs a escolha do tratamento estatístico aplicado aos resultados pode afetar a estimativa do valor verdadeiro (valor designado) e a incerteza associada, o intervalo de aceitação e a avaliação de desempenho dos laboratórios. Empregando resultados dos laboratórios participantes do Programa de Ensaio de Proficiência para chumbo em sangue (PEP-Pb-s), coordenado pelo Instituto Adolfo Lutz, São Paulo, para diferentes níveis de concentração, foram comparados sete critérios estatísticos. O valor designado foi calculado usando a mediana, ou a média após exclusão dos dispersos, empregando os critérios de Hampel, Grubbs, Dixon e Z-score. O intervalo de aceitação foi calculado pelo Z-score empregando o desvio padrão ou utilizando as equações de Horwitz ou de Horwitz modificada por Thompson. Foi também utilizado o critério atualmente empregado no Programa, que considera Xdesignado ± 6, para concentrações [Pb-s] 40 g/100mL e Xdesignado ± 15% Xdesignado para concentrações > 40 g/100mL. Verificou-se que os valores designados obtidos pelos critérios estatísticos empregados não apresentaram diferenças significantes em um nível de significância de 5%. Porém, os intervalos de aceitação obtidos mostraram-se influenciados