Discussed the influence of the stability that laboratory repeated use the HIV quality control serum during the cold storage / 国际检验医学杂志

Objective To investigate the effect of repeated use on the stability of HIV quality control serum during cold storage , and put forward measures to deal with .Methods Ten HIV serum from -20 degrees celsius freezer room temperature balance out , 30 minutes to make it completely melted ,randomly arranged in the patient sample ,added sample testing according to the normal sample ,after the end of time to save 2 to 8 degrees celsius refrigerator .The next day ,the above quality control products from 2 to 8 degrees celsius refrigerator ,after 30 minutes at room temperature ,randomly arranged in the patient sample ,add sample testing ac-cording to the normal sample ,after the end of time to save 2 to 8 degrees celsius refrigerator ,repeat the above activities to seventh days .Using repeated measure ,at the same time ,took the average 10 quality control of product values on the same day as a check-pointcompared with daily quality control chart ,observe changes .Results It suggested that in different measurement on the num-ber of days the difference was statistically significant(F=48 .515 ,P<0 .01) ,combined with the quality control chart found ,which was starting from the fourth day quality value warningstatus ,began to appear and the drift of fell out of control .Conclusion HIV quality-control serum at 2 to 8 degrees celsius refrigerator ,used repeatedly during 3 days late stability is affected ,the change of quality control diagram appear drift ,even is out of control .

Bilirubin of biochemical testing quality control serum and calibration items stability analysis / 国际检验医学杂志

Objective To grasp bilirubin in the quality control serum and calibration items in the same batch the variation law of the designed to ensure that the test quality and the use of reasonable quality control serum and calibration items ,control testing cost .Methods laboratories use The double level quality control serum and calibration items after dilution is divided into five groups ,with automatic biochemical analyzer test for 12 weeks and recorded results of TBIL ,DBIL .use SPSS 17 .0 to calculate the mean ,standard deviation ,coefficient of variation ,Normal distribution analysis and make the results trend line chart to observe any changes .Results RANDOX normal concentration quality control serum TBIL and DBIL values variation RCV% 26 .0% ,48 .2% , more than CLIA bilirubin projects allow 1/3 of the total error value(6 .67% ) .Normal distribution test ,P value was 0 .006 ,0 .012 , less than 0 .05 ,do not obey the normal distribution ,test results line chart is on the decline .LEADMAN high concentration quality control serum and bilirubin calibration items TBIL and DBIL variation RCV% 0 .05 ,obey the normal distribution ,test results no trend line chart .Conclusion Through the experiment observation to the quality control ser‐um and calibration items bilirubin in the variation law of 12 weeks .Experimenter can be used according to the actual situation to ad‐just ,not only to ensure the quality of the bilirubin test ,and to get the most out of the quality control serum and calibration items use efficiency ,reduce the test cost .

Estabilidade dos soros para o controle de qualidade interno de testes imunodiagnósticos de HIV/AIDS / Study on the stability of internal quality control sera for HIV/AIDS immunodiagnostic tests

Introduction: The use of reference materials in order to assure and perform the quality control of analytical measurements is a requirement in clinical laboratories. Objectives: Stability of serum samples, kept frozen at -20°C for long-term storage and at varied temperatures during short periods, was evaluated by investigating the persistency of anti-human immunodeficiency virus (HIV) antibodies reactivity on enzyme-linked immunosorbent assay/enzyme immunoassay (ELISA/EIA), Western blot and indirect immunofluorescence assays. Method: The analyzed sera were part of serum panels (comprised of anti-HIV positive and negative samples), produced at the Immunology Center of Instituto Adolfo Lutz, which have been the reference specimens for producing the internal quality assurance sera of HIV/acquired immunodeficiency syndrome (AIDS) immunodiagnostic assays. Sera stability was assessed in samples stored at -20°C for 56 weeks, and at various temperature conditions: from 2°C to 8°C (refrigerator), from 15°C to 25°C (room temperature), at 37°C (incubator) and at -80°C (freezer) for 24 and 48 hours. The statistical analyses on HIV-negative serum samples (long-term storage) were significant (p < 0.05), and neither adverse effects on these samples as the occurrence of false-positive results nor false-negative results in HIV antibody positive sera were found in both studies. Conclusion: It was possible to conclude that the reference material remained stable for 48 hours at different temperatures (short-term) and it remained stable at -20°C for 56 weeks (long-term)...

Introdução: A utilização de materiais de referência para assegurar e desempenhar o papel de controle de qualidade das medições analíticas é requisito em laboratórios clínicos. Objetivo: O presente estudo avaliou a estabilidade das amostras de soro, armazenadas a -20°C por um longo período de tempo e durante curto prazo em diferentes temperaturas, quanto à invariabilidade da reatividade de anticorpos contra o vírus da imunodeficiência humana (HIV), por meio de enzyme-linked immunosorbent assay/enzyme immunoassay (ELISA/EIA), Western blot e imunofluorescência indireta. Método: As amostras analisadas foram provenientes de painéis de soros (constituídos de amostras anti-HIV positivo e negativo), produzidos no Centro de Imunologia do Instituto Adolfo Lutz (IAL), os quais têm sido material de referência para o preparo de amostras do controle de qualidade interno de testes imunodiagnósticos de HIV/síndrome da imunodeficiência adquirida (AIDS). A avaliação da estabilidade dos soros foi efetuada em amostras armazenadas a -20°C por 56 semanas e nas diferentes condições de temperaturas: de 2°C a 8°C (geladeira), de 15°C a 25°C (ambiente), 37°C (estufa) e -80°C (freezer), durante 24 e 48 horas. Os resultados das análises de tendência das amostras de soro HIV negativo (armazenamento de longo prazo) foram significantes (p < 0,05) e nenhum efeito adverso foi observado nessas amostras, como a ocorrência de resultados falso-positivos, tampouco foram detectados resultados falso-negativos em amostras de soro positivas para detecção de anticorpos anti-HIV em ambas as avaliações. Conclusão: Foi possível concluir que o material de referência manteve-se estável por 48 horas nas diferentes temperaturas (curto prazo) e permaneceu estável a -20°C por 56 semanas (longo prazo)...

Estabilidad de un suero control multienzimático utilizado como material de referencia en los laboratorios clínicos / Stability of a multienzyme control serum used as reference material in clinical laboratories

Una de las vías fundamentales para garantizar la calidad de los ensayos realizados en los laboratorios clínicos es mediante el uso de materiales de referencia. Una problemática a la que nos enfrentamos es la escasez de estos productos en el mercado nacional dado su alto costo. Objetivo: evaluar la estabilidad de un suero bovino adulto enriquecido con las enzimas alanina aminotransferasa (ALAT/TGP), aspartato aminotransferasa (ASAT/TGP), fosfatasa alcalina (FA) y amilasa. Métodos: se evaluó la estabilidad a tiempo real de la matriz enriquecida con las diferentes enzimas durante 12 meses a 2 temperaturas (refrigeración y congelación). Se evaluó el efecto del glicerol sobre la actividad enzimática de los extractos, así como el efecto de los preservantes propilenglicol y etilenglicol en la estabilidad de las enzimas. Resultados: los extractos enzimáticos obtenidos comenzaron a perder la actividad biológica a partir de los 15 días, independientemente de la temperatura de almacenamiento y de la presencia o no de glicerol. Los resultados del ensayo a tiempo real realizados a la matriz enriquecida, mostraron que la estabilidad varió con el tiempo y con el tipo de enzima, independientemente del preservante ensayado, disminuyendo por debajo de los límites aceptables de actividad enzimática luego de 3 meses de almacenamiento del producto a 4 ºC. Conclusiones: se logró un material de referencia multienzimático estable por un período de 3 meses

A fundamental method to assure the quality of clinical laboratory tests is the use of reference materials. A problem we are faced with is the scarcity of these products in the domestic market, due their high cost. Objective: Evaluate the stability of an adult bovine serum enriched with the enzymes alanine aminotransferase (ALT, GPT), aspartate aminotransferase (AST, GPT), alkaline phosphatase (AP) and amylase. Methods: This enzyme-enriched matrix underwent real-time stability assessment during 12 months at two temperatures (refrigerated and frozen). An evaluation was made of the effect of glycerol on the enzymatic activity of extracts, as well as the effect of the preservatives propylene glycol and ethylene glycol on enzymatic stability. Results: The enzyme extracts obtained began to lose their biological activity at 15 days, irrespective of the storage temperature and the presence or absence of glycerol. The real time assessment of the enriched matrix showed that stability varied with time and enzyme type, irrespective of the preservative tested, and fell below acceptable limits of enzymatic activity after three months of storage at 4 ºC. Conclusions: A multienzyme reference material was obtained which was stable for a period of 3 months

Long-term consistency of 19-biochemical tests of home-made lyophilzed control serum.

Two batches of lyophilized control serum, LYOPHIL (M.Tech. Diagnostics, Thailand) and VALIDATE (General Diagnostics, USA) were distributed weekly as blind internal quality control for our central clinical chemistry laboratory. The precision of 19 biochemical tests was studied. We found that the routine condition variance (RCV) of most tests was not greater than the RCV claimed by Wilding at al except for the test of chloride and amylase. Chisquare test and Youden plot were used to analyze the two batches of control serum. The results show good correlation for both in and out control except for creatinine and phosphate. Consistency of the biochemical tests in both batches was evaluated by analysis of variance (ANOVA) of sets of consecutive 10-week period means for 1 year. Most of the mean values of each test in LYOPHIL and VALIDATE were not significantly different except those of bilirubin and creatinine (p>0.05).