ABSTRACT
Resumen La determinación de anticuerpos anti-dsDNA es de utilidad para el diagnóstico y seguimiento clínico de pacientes con lupus eritematoso sistémico (LES) y es uno de los criterios de clasificación del SLICC-2012. El objetivo del estudio fue verificar el desempeño del inmunoensayo quimioluminiscente (CLIA) QUANTA Flash dsDNA y compararlo con el método en uso de inmunofluorescencia indirecta en Crithidia luciliae (CLIFT). Se analizaron con ambos métodos 195 pacientes con diagnóstico de enfermedades del tejido conectivo y solicitud de anticuerpos anti-dsDNA. Se obtuvieron 38 sueros positivos, 133 negativos y 24 (12,3%) discordantes. Entre estos resultados discordantes, hubo 17 que correspondieron a pacientes con LES y se agruparon en 16 CLIA+/CLIFT- y 1 CLIA-/CLIFT+. Se verificó el desempeño para precisión siguiendo el protocolo EP15-A2 y la linealidad. Se estudió la concordancia mediante el coeficiente Kappa y la correlación con el coeficiente Rho de Spearman. Se observó mayor sensibilidad diagnóstica para CLIA. El grado de acuerdo fue moderado y se obtuvo buena correlación entre los valores cuantitativos de CLIA y los títulos de CLIFT. De acuerdo al buen desempeño encontrado y a los resultados discordantes analizados, la mejor estrategia para la implementación de CLIA sería utilizarla en combinación con CLIFT, lo que aumentaría la sensibilidad diagnóstica sin perder especificidad.
Abstract The detection of anti-dsDNA antibodies is useful for diagnosis and clinical monitoring of patients with systemic lupus erythematosus (SLE) and it is part of the classification criteria according to SLICC 2012. The purpose of this study was to verify the performance of the chemiluminescent immunoassay (CLIA) QUANTA Flash dsDNA and to compare it with the method currently in use, i.e the indirect immunofluorescence in Crithidia luciliae (CLIFT). One hundred and ninety five patients, who presented connective tissue diseases and required the study of anti-dsDNA antibodies, were analyzed. Thirty eight positive serum samples were obtained, 133 were negative and 24 (12.3%) in disagreement. Within the discordant results, there were 17 that corresponded to patients with SLE and they were grouped in 16 CLIA+/CLIFT- and 1 CLIA-/CLIFT+. The accuracy performance was assessed according to the EP15-A2 protocol and linearity. Concordance and correlation were calculated with the Kappa and Spearman's Rho coefficient, respectively. Based on the good performance observed and the discordant results analyzed, the best strategy for CLIA implementation would be to combine it with CLIFT, which would increase the diagnostic sensitivity without losing specificity.
Resumo A determinação dos anticorpos anti-dsDNA é de utilidade para o diagnóstico e seguimento clinico de pacientes com lúpus eritematoso sistêmico (LES) e é um dos critérios de classificação do SLICC 2012. O objetivo do estudo foi verificar o desempenho do imunoensaio quimioluminescente (CLIA) QUANTA Flash dsDNA e compará-lo com o método em uso imunofluorescência indireta em Crithidia luciliae (CLIFT). Foram analisados com os dois métodos, 195 pacientes com diagnóstico de doenças do tecido conjuntivo e solicitude de anticorpos anti-dsDNA. Os resultados foram agrupados em 38 soros positivos, 133 negativos e 24 (12,3%) discordantes. Entre esses resultados discordantes, 17 corresponderam a pacientes com LES e se agruparam em 16 CLIA+/CLIFT- e 1 CLIA-/CLIFT+. Foi verificado o desempenho para precisão seguindo o protocolo EP15-A2 e a linearidade. Foi estudada a concordância mediante o coeficiente Kappa e correlação com o coeficiente Rho de Spearman. Observou-se maior sensibilidade diagnóstica para CLIA. O grau de acordo foi moderado e boa correlação foi observada entre os valores quantitativos de CLIA e os títulos de CLIFT. Com base no bom desempenho encontrado e nos resultados discordantes analisados, a melhor estratégia para implementar o CLIA seria utilizá-lo em combinação com o CLIFT, o que aumentaria a sensibilidade do diagnóstico sem perder a especificidade.
ABSTRACT
BACKGROUND: Syphilis remains a public health concern worldwide, the accuracy of diagnostic tests is critical for its successful control. Currently, there are two approaches to the diagnosis of syphilis using serological tests: the traditional algorithm and the reverse algorithm. AIM: The goal of this study was to analyse the advantages and disadvantages in the implementation of the syphilis reverse-screening algorithm in an outpatient clinical laboratory. METHODS: An observational cross-sectional study was carried out analyzing 246 reactive sera from a total of 14700 requests for syphilis serology. Chemiluminescent assay ARCHITECT Syphilis TP, V.D.R.L. and FTA-Abs were performed. RESULTS: Among 246 reactive sera by ARCHITECT Syphilis TP, 129 were reactive and 117 were non-reactive by V.D.R.L. the last mentioned resulted in 97 reactive and 20 non-reactive by FTA-Abs, suggesting false positives (0.13%). Two patients with primary infection were detected, that were not detected by V.D.R.L. and one pregnant woman with primary infection with a high value S/CO and V.D.R.L.:1 dils. CONCLUSIONS: Among the advantages of using a reverse algorithm were greater sensitivity in the detection of patients with primary syphilis; automation, complete traceability of the samples; objective interpretation and conclusive results.
Subject(s)
Mass Screening/methods , Syphilis Serodiagnosis/methods , Syphilis/diagnosis , Treponema pallidum/isolation & purification , Adolescent , Adult , Aged , Aged, 80 and over , Algorithms , Cross-Sectional Studies , Female , Humans , Luminescent Measurements , Male , Middle Aged , Pregnancy , Sensitivity and Specificity , Treponema pallidum/immunology , Young AdultABSTRACT
Resumen Introducción: La sífilis sigue siendo un problema de salud pública en todo el mundo; la precisión de las pruebas de diagnóstico es fundamental para el éxito de su control. Actualmente, hay dos enfoques para el diagnóstico serológico de la sífilis: el algoritmo tradicional y el algoritmo reverso. Objetivo: Analizar las ventajas y desventajas en la implementación del cribado para sífilis con el algoritmo reverso en un laboratorio clínico de pacientes ambulatorios. Materiales y Métodos: Se realizó un estudio de corte transversal analizando 246 sueros reactivos en el cribado sobre un total de 14.700 solicitudes de serología para sífilis. Se utilizaron los ensayos ARCHITECT SyphilisTP, V.D.R.L. y FTA-Abs. Resultados: De los 246 sueros reactivos por ARCHITECT Syphilis TP, 129 fueron reactivos y 117 no reactivos con V.D.R.L., éstos últimos resultaron 97 reactivos y 20 no reactivos por FTA-Abs, sugiriendo falsos positivos (0,13%). Se detectaron dos casos de infección primaria, no detectados con V.D.R.L y un caso de infección primaria en una gestante con un valor alto S/CO y V.D.R.L. de 1 dils. Conclusiones: Entre las ventajas de utilizar el algoritmo reverso se encontró mayor sensibilidad en la detección de sífilis primaria; automatización, trazabilidad, interpretación objetiva y resultados concluyentes.
Background: Syphilis remains a public health concern worldwide, the accuracy of diagnostic tests is critical for its successful control. Currently, there are two approaches to the diagnosis of syphilis using serological tests: the traditional algorithm and the reverse algorithm. Aim: The goal of this study was to analyse the advantages and disadvantages in the implementation of the syphilis reverse-screening algorithm in an outpatient clinical laboratory. Methods: An observational cross-sectional study was carried out analyzing 246 reactive sera from a total of 14700 requests for syphilis serology. Chemiluminescent assay ARCHITECT Syphilis TP, V.D.R.L. and FTA-Abs were performed. Results: Among 246 reactive sera by ARCHITECT Syphilis TP, 129 were reactive and 117 were non-reactive by V.D.R.L. the last mentioned resulted in 97 reactive and 20 non-reactive by FTA-Abs, suggesting false positives (0.13%). Two patients with primary infection were detected, that were not detected by V.D.R.L. and one pregnant woman with primary infection with a high value S/CO and V.D.R.L.:1 dils. Conclusions: Among the advantages of using a reverse algorithm were greater sensitivity in the detection of patients with primary syphilis; automation, complete traceability of the samples; objective interpretation and conclusive results.
Subject(s)
Humans , Male , Female , Pregnancy , Adolescent , Adult , Middle Aged , Aged , Aged, 80 and over , Young Adult , Treponema pallidum/isolation & purification , Syphilis Serodiagnosis/methods , Syphilis/diagnosis , Mass Screening/methods , Treponema pallidum/immunology , Algorithms , Cross-Sectional Studies , Sensitivity and Specificity , Luminescent MeasurementsABSTRACT
Introducción: El laboratorio debe garantizar la estabilidad de las muestras conservadas con la finalidad de una eventual confirmación de resultados o corregir posibles errores u omisiones al ingresar las solicitudes médicas. Con este objetivo se comparó la estabilidad de los analitos de muestras conservadas en el tubo primario selladas con film contra cierre con tapa plástica. Material y métodos: Veinticuatro muestras de sangre fueron alicuotadas en dos tubos primarios, uno cerrado con tapa plástica y otro con film. A ambas alícuotas se les midieron 26 analitos de química clínica durante siete días consecutivos, en un autoanalizador Cobas c 501 de Roche y se conservaron en refrigerador a 2-8°C. Se calcularon los coeficientes de variación y el error total. Los resultados obtenidos se compararon con el requisito de calidad respectivo establecido por el laboratorio. Conclusiones: Se observó una mayor variabilidad en los tubos cerrados con film respecto de los cerrados con tapa plástica. Todas las enzimas evaluadas cumplieron el requisito de calidad durante 4 días. A excepción del hierro todos los iones fueron estables solo un día. Los metabolitos fueron estables durante una semana a excepción de glucosa, proteínas totales, ácido úrico y albúmina. Se recomienda que cada laboratorio evalúe la estabilidad de los analitos en base a su forma de trabajo
Introduction: The laboratory must be able to guarantee the stability of stored patient samples for confirmation of results or errors in the interpretation of the medical request. The aim of this study was to evaluate the stability of the blood analytes preserved in tubes sealed with film versus a plastic cap. Material and methods: A total of 24 blood samples were aliquoted into two tubes; one sealed with film, and the other with a plastic cap. Twenty-six clinical chemistry analytes were measured for 7 consecutive days using a Roche Cobas c 501 autoanalyser. The samples were stored in a refrigerator between 2-8C. The total error and coefficient of variation were calculated, and the results were compared against the quality requirements of the laboratory. Conclusions: The variation was higher in the tubes sealed with film than in those with a plastic cap. Enzymes remained within the quality requirements for four days, and ions, apart from iron, were stable for only one day. The metabolites were stable for seven days excluding glucose, uric acid, total proteins, and albumin. It is suggested that each laboratory must evaluate the stability of analytes based on its workflow
Subject(s)
Humans , Preservation of Water Samples/methods , Reactivity-Stability , Clinical Laboratory Techniques/standards , Blood Preservation/standards , 34002 , Laboratory Proficiency Testing/methodsABSTRACT
El objetivo del presente trabajo fue estudiar la presencia de reactividad cruzada de la prueba de tamizaje htTG/DGP para enfermedad celíaca (EC) con otros autoanticuerpos presentes en altos títulos en diferentes enfermedades autoinmunes (EA). Se realizó un estudio de corte transversal donde se seleccionaron 100 pacientes no celíacos, de ambos sexos (15 hombres, 85 mujeres) con edades entre 4 y 86 años que presentaban diversas EA. Para estudiar presencia de EC se realizaron por ELISA los ensayos QUANTALite® (INOVA Diagnostics, EE.UU.): htTG/DGPScreen, htTG IgA e IgG, Gliadina IgAII e IgGII. Los autoanticuerpos de otras EA se determinaron por inmunofluorescencia indirecta y por electroquimioluminiscencia. La reactividad cruzada encontrada con autoanticuerpos no específicos de EC fue de 2,0%. Las dos muestras positivas con la prueba de tamizaje (23,0 U y 24,9 U) presentaron anticuerpos anti-centrómero y anti-nucleares, con títulos 1/1280 y 1/640 respectivamente. Las mismas fueron analizadas para los marcadores de celiaquía y sólo una resultó positiva débil (21,8 U) para anti-Gliadina IgAII. La baja reactividad cruzada hallada con el ensayo de tamizaje htTG/DGP en presencia de otros autoanticuerpos permite concluir que dicha prueba constituye una herramienta de gran utilidad para la pesquisa de EC en pacientes con diferentes enfermedades autoinmunes.
The goal of this study was to show the presence of cross-reactivity screening test htTG/DGP for celiac disease (CD) with other autoantibodies present in high titers in different autoimmune diseases (AD). A cross-sectional study was performed for which 100 patients of both sexes (15 men, 85 women), aged between 4 and 86 years without CD who had different autoimmune pathologies were selected. To study the presence of CD, QUANTALite® (INOVA Diagnostics, USA): htTG/DGP Screen, htTG IgA and IgG, Gliadin IgAII and IgGII tests by ELISA were used. Other autoantibodies from AD were determined by indirect immunofluorescence and by electrochemiluminescence. Cross-reactivity with non-specific autoantibodies found in EC was 2.0%. The two positive samples of screening test (23,0 U and 24,9 U) had anti-centromere antibodies 1/1280 and anti-nuclear antibodies 1/640 respectively. They were analyzed for celiac disease markers and only one was weak positive (21,8 U) for anti-Gliadin IgAII. The low cross reactivity found with screening test htTG/DGP in the presence of other autoantibodies made it possible to conclude that this test is a useful tool for screening of CD in patients with different autoimmune diseases.
O objetivo deste trabalho foi estudar a presença de reatividade cruzada do teste de screening htTG/ DGP para a doença celíaca (DC) com outros autoanticorpos presentes em altos títulos em diferentes doenças autoimunes (DA). Foi realizado um estudo transversal para o qual foram selecionados 100 pacientes não-celíacos, de ambos os sexos (15 homens, 85 mulheres), com idades entre 4 e 86 anos que apresentavam diferentes patologias autoimunes (DA). Para estudar a presença de DC, realizaram-se por ELISA os ensaios QUANTALite® (INOVA Diagnostics, EUA): htTG/DGPScreen, htTG IgA e IgG, Gliadina IgAII e Gliadina IgGII por ELISA. Os autoanticorpos das outras DA foram determinados por imunofluorescência indireta e por eletroquimioluminescência. A reatividade cruzada encontrada com outros autoanticorpos não específicos de DC foi de 2,0%. As duas amostras positivas para o teste de screening (23,0 U e 24,9 U) apresentaram anticorpos anticentrômeros e antinucleares, com títulos 1/1280 e 1/640 respectivamente. Elas foram analisadas para os marcadores de doença celíaca e apenas uma resultou positiva fraca (21,8 U) para anti-Gliadina IgAII. A baixa reatividade cruzada encontrada com o teste de screening htTG/DGP em presença de outros autoanticorpos, permite concluir que este teste constitui um instrumento de grande utilidade para a pesquisa de doença celíaca em pacientes com diferentes doenças autoimunes.
Subject(s)
Humans , Male , Female , Child, Preschool , Child , Adolescent , Adult , Middle Aged , Aged , Aged, 80 and over , Celiac Disease , Cross-Priming , Autoantibodies/analysis , Autoimmune Diseases , Straining of Liquids/methodsABSTRACT
El objetivo del trabajo consistió en evaluar la relación entre los niveles de lípidos y parámetros que definen el estado de insulinorresistencia con la edad, el estado menopáusico (EM) y el índice de masa corporal (IMC) en la pre- y postmenopausia. En este estudio de corte transversal se seleccionaron 89 mujeres: 42 premenopáusicas (Pre) y 47 postmenopáusicas (Post). Se midieron: FSH, LH, estradiol e insulina por MEIA, colesterol total (CT), triglicéridos (TG), colesterol de lipoproteínas de baja densidad (C-LDL), colesterol de lipoproteínas de alta densidad (C-HDL) y glucosa por métodos químicos convencionales. El colesterol de LDL pequeñas y densas (C-LDLpyd) se obtuvo por cálculo. Las pacientes Post mostraron niveles más elevados de CT (p<0,0001), C-LDL (p<0,0001), C-HDL (p=0,0283), TG (p=0,0014), C-LDLpyd (p=0,0001), CT/C-HDL (p=0,0016) y glucosa (p=0,0048) que las Pre. No se hallaron diferencias significativas en los valores de insulina ni del índice TG/C-HDL. El análisis de regresión múltiple mostró que los valores de CT, C-LDL y C-HDL se relacionaron lineal y positivamente con la edad. Los niveles de C-LDL medido, TG, CT/C-HDL, C-LDLpyd, glucosa, insulina y TG/C-HDL se asociaron positivamente con IMC. C-HDL se relacionó negativamente con IMC. Sólo el C-LDLpyd presentó linealidad positiva con el EM.
The purpose of this study was to evaluate the relationship between lipid levels and insulin resistance parameters with age, menopausal status (MS) and body mass index (BMI) in pre- and postmenopausal women. This cross-sectional study included 89 women: 42 premenopausal (Pre) and 47 postmenopausal (Post). FSH, LH, estradiol and insulin were measured by MEIA. Total-cholesterol (TC), triglycerides (TG), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), and glucose were measured by conventional clinical chemistry methods. Small and dense LDL-C (sdLDL-C) was estimated by calculation. Post women showed higher values of TC (p<0.0001), LDL-C (p<0.0001), HDL-C (p=0.0283), TG (p=0.0014), sdLDL-C (p=0.0001), TC/HDL-C ratio (p=0.0016) and glucose (p=0.0048) than Pre. Insuline and TG/HDL-C ratio were not different between groups. Multiple regression analysis showed TC, LDL-C and HDL-C levels to be linearly and positively associated to age. Measured LDL-C, TG, TC/HDL-C ratio, sdLDL-C, glucose, insulin and TG/HDL-C ratio showed linear and positive relationship with BMI. HDL-C was negatively associated to IMC. Only sdLDL-C concentrations were associated positively to MS.
O objetivo deste trabalho é avaliar a relação entre os níveis de lipídios e parâmetros que definem o estado de resistência à insulina com a idade, estado menopausal (EM) e índice de massa corporal (IMC) na pré- e pós-menopausa. Neste estudo de corte transversal, foram selecionadas 89 mulheres: 42 pré-menopausa (Pré) e 47 pós-menopausa (Pós). Foram medidos: FSH, LH, estradiol e insulina pelo MEIA. Colesterol total (CT), triglicerídeos (TG), colesterol de lipoproteínas de baixa densidade (C-LDL), colesterol de lipoproteínas de alta densidade (C-HDL) e glicose através de métodos químicos convencionais. O colesterol de LDL pequenas e densas (C-LDLpyd) foi obtido por cálculo. Pacientes Pós-menopausa apresentaram níveis mais altos de CT (p<0,0001), C-LDL (p<0,0001), C-HDL (p=0,0283), TG (p=0,0014), C-LDLpyd (p=0,0001), CT/C-HDL (p=0,0016) e glicose (p=0,0048) do que as Pré-menopausa. Não foram encontradas diferenças significativas nos valores de insulina nem do índice de TG/C-HDL. A análise de regressão múltipla mostrou que os valores de CT, C-LDL e C-HDL foram linear e positivamente relacionados com a idade. Os níveis de C-LDL medido, TG, CT/C-HDL, C-LDLpyd, glicose, insulina e TG/C-HDL foram associados positivamente com IMC. C-HDL se relacionou negativamente com IMC. Apenas o C-LDLpyd apresentou linearidade positiva com o EM.
Subject(s)
Humans , Female , Middle Aged , Aged , Body Mass Index , Insulin Resistance , Postmenopause , Premenopause , Evaluation StudyABSTRACT
El valor de referencia del cambio (VRC) es el valor máximo que es permisible cambie el resultado de un analito entre dos mediciones sucesivas en un mismo paciente, sin que esta diferencia sea de relevancia clínica. Incluye critérios basados en la variabilidad biológica intraindividual (CVI) y la imprecisión analítica (CVA). La principal utilidad de los marcadores tumorales (MT) es el monitoreo de pacientes, resultando más apropiado informar el VRC que evaluar un resultado con su valor de referencia, como lo indica su bajo índice de individualidad. El objetivo fue evaluar la utilidad del VRC para detectar un cambio significativo entre resultados sucesivos en los principales MT. Se analizaron datos de sueros de controles de calidad de MT desde mayo de 2010 a febrero de 2014, se calculó el CVA%, y los datos de CVI % fueron obtenidos de bibliografía. Se calcularon los VRC para cada MT. Para los MT evaluados: AFP, CEA, CA125, CA15-3, CA19-9, PSA y tiroglobulina, los VRC fueron: 29.7, 32.3, 58.0, 16.3, 38.3, 42.7 y 34.2% respectivamente (p<0.05). Estos valores se compararon con datos bibliográficos. El VRC es un dato útil para el médico ya que colabora en la correcta interpretación de resultados seriados durante el seguimiento de pacientes, en la evaluación del tratamiento o en la estimación de recurrencias. Le permite saber si la diferencia encontrada entre dos valores consecutivos representa un cambio em el estado de salud del paciente. Nuestros VRC resultaron comparables con los de literatura
The reference change value (RCV) is the maximum allowable change between two consecutive results with no meaningful clinical relevance. It is analyzed within individual biological variability (CVI ) and analytical imprecision (CVA) criteria. For tumor markers (TM) monitoring is more appropriate to report RCV than reference interval due to their low individuality index. The aim of the study was to evaluate the usefulness of RCV to indicate a significant change between two consecutives TM results. Data from MT quality control serums (QC) were analyzed from May 2010 to February 2014, the imprecision was calculated as CVA% and CVI % data was obtained from literature. The RCV for each MT was calculated. The RCV for AFP, CEA, CA125, CA15-3, CA19-9, PSA and thyroglobulin were 29.7, 32.3, 58.0, 16.3, 38.3, 42.7 and 34.2% respectively (p < 0.05). These values were compared with literature data. The RCV is an appropriate tool for the clinicians and aids for the correct interpretation of results in the monitoring of patients, in treatment evaluation or estimation of recurrence. Physicians can determine whether the differences found between two successive values represent a change in the health status of the patient. The RCV calculated were comparable with those obtained in literature
