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2.
Arch. endocrinol. metab. (Online) ; 65(2): 237-241, Mar.-Apr. 2021. tab
Article in English | LILACS | ID: biblio-1248806

ABSTRACT

SUMMARY Falsely elevated estradiol is rare, may result from heterophile antibody interference, and can result in unnecessary investigation and intervention. We present the case of a 56-year-old female with falsely elevated estradiol levels inconsistent with her overall clinical picture, which ultimately led to an unnecessary surgical procedure. With the use of alternative analytical platforms and a heterophile antibody blocking agent, we determined the false elevation was due to heterophile antibody interference. Clinicians must suspect and investigate for laboratory error when the clinical picture contradicts laboratory results.


Subject(s)
Humans , Female , Antibodies, Heterophile , Estradiol , Immunoassay , False Positive Reactions , Middle Aged
3.
Rev. argent. salud publica ; 13(Suplemento COVID-19): 1-4, 2021.
Article in Spanish | LILACS, BINACIS, ARGMSAL | ID: biblio-1247637

ABSTRACT

La detección de genoma viral mediante la técnica de reacción en cadena de la polimerasa con transcripción inversa en tiempo real (rRTPCR) para detectar virus SARS CoV-2, se considera como referencia para la definición de caso de enfermedad por coronavirus 2019 (COVID-19) confirmado por laboratorio. Sin embargo, no es lo mismo detectar genoma viral que diagnosticar una enfermedad, y la sensibilidad de detección de la técnica puede exceder la significancia clínica. En microbiología, la jerarquización de un resultado positivo depende de factores como el contexto clínico y epidemiológico, el sitio de toma de muestra y, en muchos casos, la cuantificación del patógeno. Un parámetro fundamental de la rRT-PCR es el ciclo umbral. De su interpretación depende la clasificación de una persona como caso confirmado. Por otro lado, los valores predictivos de una prueba varían según la prevalencia de la patología buscada. Dado que las pruebas positivas obtenidas en diferentes escenarios se consideran de manera equivalente como casos confirmados, con independencia de los signos y síntomas, puede haberse producido una sobrestimación de los casos reales de COVID-19, principalmente en función de testeos realizados en población general. Es fundamental el entrenamiento del personal y la realización de controles de calidad en los laboratorios de diagnóstico, así como definir niveles de corte de ciclo umbral predictivos de infectividad en centros de referencia para minimizar el impacto de resultados falsos en la sociedad


Subject(s)
Predictive Value of Tests , Coronavirus Infections , False Positive Reactions , Real-Time Polymerase Chain Reaction , Betacoronavirus
4.
Rev. Paul. Pediatr. (Ed. Port., Online) ; 39: e2020231, 2021. tab, graf
Article in English | LILACS, SES-SP | ID: biblio-1136757

ABSTRACT

ABSTRACT Objective: To present the current evidence on clinical and laboratory characteristics of infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during childhood and adolescence. Data source: This is a narrative review conducted in the databases: Medical Literature Analysis and Retrieval System Online (MEDLINE/PubMed), Latin American and Caribbean Health Sciences Literature in the Virtual Health Library (LILACS/VHL), Scopus, Web of Science, Cochrane Library, portal of the Coordination for the Improvement of Higher Education Personnel (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES), Scientific Electronic Library Online (SciELO), ScienceDirect, and Cumulative Index to Nursing and Allied Health Literature (CINAHL). The terms used were SARS-CoV-2, COVID-19, novel coronavirus, child, newborn, and adolescent. Data synthesis: Unlike adults, most children infected by SARS-CoV-2 have mild or asymptomatic clinical presentations. Symptomatic children mainly have low fever and cough, with some associated gastrointestinal symptoms. Severe cases are rare and occur especially in infants under one year of age. Detection of viral particles in feces seems to be more persistent in children and can be used as a tool for diagnosis and control of the quarantine period. Different from adults, children can present distinct inflammatory responses, as has happened in new cases of Kawasaki-like syndrome associated with SARS-CoV-2 infection. Conclusions: Most children have asymptomatic or mild presentations, with a prevalence of fever, cough, and gastrointestinal symptoms. New cases with different systemic inflammatory reactions in children have been reported, with clinical manifestations distinct from those typically found in adults.


RESUMO Objetivo: Apresentar as atuais evidências sobre as características clínicas e laboratoriais da infecção pelo coronavírus da síndrome respiratória aguda grave 2 (SARS-CoV-2) durante a infância e a adolescência. Fonte de dados: Revisão narrativa realizada nas bases de dados Medical Literature Analysis and Retrieval System Online (MEDLINE/PubMed), Literatura Latino-Americana e do Caribe em Ciências da Saúde na Biblioteca Virtual em Saúde (LILACS/BVS), Scopus, Web of Science, Cochrane Library, portal da Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Scientific Electronic Library Online (SciELO), ScienceDirect e Cumulative Index to Nursing and Allied Health Literature (CINAHL), com o uso dos termos SARS-CoV-2, COVID-19 e novo coronavírus e criança, recém-nascido e adolescente. Síntese dos dados: Diferentemente dos adultos, as crianças infectadas pelo SARS-CoV-2 apresentam formas clínicas leves ou assintomáticas na maior parte dos casos. As crianças sintomáticas apresentam predominantemente febre baixa e tosse, com alguns sintomas gastrointestinais associados. Casos graves são a minoria e ocorrem especialmente abaixo de um ano de idade. A detecção de partículas virais em fezes parece ser mais persistente em crianças, podendo servir como ferramenta diagnóstica e de controle do tempo de quarentena. Diferentemente dos adultos, as crianças podem apresentar respostas inflamatórias distintas, como tem ocorrido nos novos casos de síndrome de Kawasaki-like associada à infecção pelo SARS-CoV-2. Conclusões: Crianças, na sua maioria, apresentam quadros assintomáticos ou leves, com predomínio de febre, tosse e sintomas gastrointestinais. Novos relatos de diferentes reações sistêmicas inflamatórias em crianças têm sido notados, com manifestações clínicas distintas daquelas tipicamente observadas em adultos.


Subject(s)
Humans , Female , Infant, Newborn , Infant , Child , Adolescent , Pneumonia, Viral/diagnosis , Coronavirus Infections/diagnosis , Clinical Laboratory Techniques/methods , Betacoronavirus , Severity of Illness Index , False Negative Reactions , False Positive Reactions , Pandemics , COVID-19 Testing , SARS-CoV-2 , COVID-19
5.
Rev. bras. ortop ; 55(5): 537-542, Sept.-Oct. 2020.
Article in English | LILACS | ID: biblio-1144207

ABSTRACT

Abstract The influence of genetic inheritance has been increasingly investigated in shoulder disorders, such as rotator cuff injury, instability and frozen shoulder. Although the initial findings are enlightening, it is necessary to progressively build a database of genetic markers to catalog genomic profiles that, later, may contribute for predicting the risk of the disease, as well as to the development of better diagnostic and treatment tools. The present article seeks to update what is evidence of genetic studies in the literature for these diseases, from polymorphism analyses, expression of candidate genes in tissues and broad genomic association studies (GWAS). However, it is necessary to point out that there is great difficulty in replicating and using the findings, mainly due to the lack of statistical power, the high rate of false-positive results and the large number of variables involved.


Resumo A influência da herança genética tem sido cada vez mais investigada nas afecções do ombro, como a lesão do manguito rotador, instabilidade e ombro congelado. Ainda que os achados iniciais sejam pouco esclarecedores, é necessário construir progressivamente um banco de marcadores genéticos para catalogar perfis genômicos que, mais adiante, poderão contribuir para a previsão do risco da doença, desenvolvimento de melhores ferramentas de diagnóstico e tratamento. O presente artigo busca atualizar o que há de evidências de estudos genéticos na literatura para essas doenças, desde análises de polimorfismos, expressão de genes candidatos em tecidos e estudos de associação genômica ampla (GWAS, na sigla em inglês). Porém, é necessário apontar que existe grande dificuldade na replicação e utilização dos achados, principalmente em razão da falta de poder estatístico, da alta taxa de resultados falso-positivos e da grande quantidade de variáveis envolvidas.


Subject(s)
Polymorphism, Genetic , Shoulder , Wounds and Injuries , Bursitis , Genetic Markers , Gene Expression , Incidence , Rotator Cuff , Heredity , Diagnosis , False Positive Reactions , Rotator Cuff Injuries
6.
Rev. Hosp. Ital. B. Aires (2004) ; 40(3): 117-125, sept. 2020. ilus, tab
Article in Spanish | LILACS | ID: biblio-1129078

ABSTRACT

En diciembre de 2019 se identificó el virus SARS-CoV-2, cuya rápida propagación global puso en estado de emergencia al mundo entero, llevando al ser humano a una situación sin antecedente cercano. El objetivo de esta revisión es describir los métodos diagnósticos utilizados actualmente para identificar la infección por SARS-CoV-2. Las manifestaciones clínicas y el espectro imagenológico de la enfermedad son muy inespecíficos y no permiten realizar un diagnóstico certero. Por esta razón, es esencial una apropiada toma de muestra respiratoria en el momento y sitio anatómico adecuado para un diagnóstico preciso de COVID-19. La técnica de muestreo más utilizada es el hisopado nasofaríngeo y la prueba diagnóstica más fiable se basa en la retrotranscripción seguida por reacción en cadena de la polimerasa en tiempo real (RT-PCR). No obstante, existen otras técnicas moleculares, como también tests serológicos para detectar anticuerpos o fragmentos antigénicos del SARS-CoV-2. Más allá de la precisión diagnóstica, es importante tener en cuenta la probabilidad basal (pretest) para interpretar correctamente el resultado obtenido y aislar aquellos posibles falsos negativos. Con el objetivo de evitar la saturación del sistema de salud es imprescindible contar con información y métodos diagnósticos precisos para detectar tempranamente los focos de infección y reducir la transmisión comunitaria, utilizando eficazmente los diferentes recursos diagnósticos. (AU)


In December 2019, the SARS-CoV-2 virus was identified for the first time, whose rapid global spread put the entire world in a state of emergency, leading humans to an unprecedented situation with no immediate history. The main purpose of this review is to describe the diagnostic methods currently used to identify SARS-CoV-2 infection. The clinical manifestations and the imaging spectrum of the disease are nonspecific and do not allow an accurate diagnosis to be made. For this reason, an appropriate respiratory sampling at the right time and anatomical site is essential for an accurate diagnosis of COVID-19. The most widely used sampling technique is nasopharyngeal swab, and the most reliable diagnostic test is by reverse transcription followed by real-time polymerase chain reaction (RT-PCR). However, there are other molecular techniques, as well as serological tests to detect antibodies or antigenic fragments of SARS-CoV-2. Beyond the diagnostic precision, it is important to take into account the baseline probability (pre-test) to correctly interpret the result obtained and isolate those possible false negatives. In order to avoid saturation of the health system, it is essential to have accurate information and diagnostic methods to detect outbreaks of infection in early stages and to reduce communitary transmission, making effective use of the various diagnostic resources. Coronavirus infections/diagnosis, viral/diagnosis, pandemics, clinical laboratory techniques, real-time polymerase chain reaction, antigens, viral/analysis. (AU)


Subject(s)
Humans , Serologic Tests/methods , Coronavirus Infections/diagnosis , Real-Time Polymerase Chain Reaction/methods , Argentina , Pneumonia, Viral/diagnosis , Serologic Tests/statistics & numerical data , Polymerase Chain Reaction/methods , Polymerase Chain Reaction/statistics & numerical data , Coronavirus Infections/physiopathology , Coronavirus Infections/prevention & control , Coronavirus Infections/diagnostic imaging , False Negative Reactions , False Positive Reactions , Real-Time Polymerase Chain Reaction/statistics & numerical data , Betacoronavirus
7.
Rev. argent. salud publica ; 12(Suplemento Covid-19): 1-7, 23 de Julio 2020.
Article in Spanish | LILACS, BINACIS, ARGMSAL | ID: biblio-1145389

ABSTRACT

El manejo de las infecciones virales respiratorias, tanto a nivel nacional como a nivel mundial, requiere resultados científicos de calidad. La reacción en cadena de la polimerasa de transcriptasa inversa (rRT-PCR, por su sigla en inglés) es considerada el "patrón de oro" para detectar el genoma del nuevo coronavirus 2 (SARS-CoV-2), agente causal de la enfermedad por el nuevo coronavirus (COVID-19) sobre todo en la fase aguda de la infección. Su uso es controvertido fuera de un contexto de exposición viral. El objetivo del presente trabajo es analizar escollos encontrados durante la detección del genoma del SARS-CoV-2 que pueden producir resultados falsos. Los falsos negativos de rRT-PCR pueden deberse al momento y la eficacia de la toma de la muestra, la congelación, el almacenamiento y la descongelación, y a la inactivación térmica de la virulencia. Además, las señales retardadas de los controles internos invalidan la negatividad. Por otra parte, las muestras con escaso material biológico llevan a conclusiones negativas falsas, por lo que determinar un umbral (número mínimo de células epiteliales) contribuirá a reducirlas. Sin embargo, la mayoría de los kits detectan ADN humano, pero no fueron calibrados para cuantificar carga celular. Los ácidos ribonucleicos nucleares (ARN) virales adheridos a guantes, tubos y gorros, -entre otros elementos-, son fuente de falsos positivos. Las farmacopeas sugieren que la contaminación externa se controle en series de 100 muestras con al menos una representatividad del 10%. Si se extrapola esta aproximación al laboratorio de análisis clínicos, en lugar de uno se deberían procesar al menos 10 controles negativos contiguos a 10 positivos cada 100 pruebas. Mejorar la detección por rRT-PCR implica un aumento de al menos 20% en el costo de los reactivos, por lo que se necesitan recursos adicionales.


Subject(s)
Coronavirus Infections , Reverse Transcriptase Polymerase Chain Reaction , False Negative Reactions , False Positive Reactions
8.
Rev. colomb. cardiol ; 27(3): 186-188, May-June 2020. tab
Article in Spanish | LILACS, COLNAL | ID: biblio-1289210

ABSTRACT

Resumen La troponina cardiaca es el marcador bioquímico más sensible y específico de daño/necrosis miocárdica, de ahí que desempeñe un papel crucial en el diagnóstico del síndrome coronario agudo. Sin embargo, en ocasiones, como en el caso clínico que se describirá, la elevación anormal de troponina no siempre obedece a un síndrome coronario agudo trombótico, sino a causa cardiaca sin enfermedad coronaria significativa, causa extracardiaca o alteración analítica (verdaderos falsos positivos). El interés de este caso radica en que siempre debería tenerse en mente la posibilidad de que se produzca un falso positivo de troponina por causa analítica, en especial en situaciones clínicas sin una razón obvia de daño miocárdico y cuando no sea evidente la confirmación de daño miocárdico mediante pruebas complementarias.


Abstract Cardiac troponin is the most sensitive and specific biochemical marker for myocardial damage / necrosis, and thus has a crucial role in the diagnosis of acute coronary syndrome. However, occasionally, as in the clinical case that will be described, the abnormal elevation of troponin does not always obey that of an acute coronary syndrome, but also to a cardiac cause with no significant coronary disease, extra-cardiac cause, or analytical change (true false positives). The interest in this case lies in that it should always be borne in mind that a false positive troponin can be produced due to an analytical cause. This can be the case in clinical situations with no obvious reason for myocardial damage and when the confirmation of myocardial damage may not be evident using complementary tests.


Subject(s)
Humans , Male , Middle Aged , Troponin I , False Positive Reactions , Lifting , Coronary Disease , Acute Coronary Syndrome
10.
Rev. Soc. Bras. Med. Trop ; 53: e20200351, 2020. graf
Article in English | LILACS, ColecionaSUS, SES-SP | ID: biblio-1136900

ABSTRACT

Abstract INTRODUCTION: Estimates of the number of individuals infected by severe acute respiratory syndrome coronavirus 2 are important for health planning and establishment of expectations regarding herd immunity. METHODS: Seven testing rounds of a serological survey were conducted at 1-week intervals between April 19 and May 31, 2020 in Teresina municipality. RESULTS Over the 7 weeks, serological positivity increased from 0.56% (95% confidence interval [CI]: 0.18%-1.30%) to 8.33% (95% CI: 6.61%-10.33%), representing 33-53 persons infected for each reported case. CONCLUSIONS: Serological screening may be an important tool for understanding the immunity of a population and planning community interventions.


Subject(s)
Humans , Pneumonia, Viral/epidemiology , Coronavirus Infections/epidemiology , Betacoronavirus/immunology , Pneumonia, Viral/diagnosis , Pneumonia, Viral/immunology , Brazil/epidemiology , Confidence Intervals , Seroepidemiologic Studies , Sensitivity and Specificity , Coronavirus Infections , Coronavirus Infections/diagnosis , Coronavirus Infections/immunology , Immunity, Herd , False Positive Reactions , Asymptomatic Diseases/epidemiology , Pandemics , Betacoronavirus
13.
Rev. chil. dermatol ; 35(4): 128-133, 2019. graf
Article in Spanish | LILACS | ID: biblio-1120273

ABSTRACT

Introducción: La sífilis gestacional continúa sien-do un problema de salud pública en el mundo. Produce severos efectos adversos en la madre y en el feto de no ser tratada. En Chile, el Ministerio de Salud ha establecido un tamizaje para esta infección cada 3 meses en el embarazo y al momento del parto. Un tratamiento adecuado y oportuno es capaz de prevenir todos los efectos adversos de la sífilis en el embarazo. Métodos: Este fue un estudio transversal retrospectivo que incluyó a 406 embarazadas controladas en la Unidad de Atención y Control en Salud Sexual (UNACESS) del Hospital San José (HSJ) entre los años 2010-2016. Resultados: Los resultados del estudio fueron que un 87,7% de las embarazadas eran chilenas y un 12,3% de otras nacionalidades. Las nacionalidades más frecuentes para el grupo de extranjeras fueron: 54% peruanas y 18% haitianas. Al ingreso al estudio, 47,5% de las embarazadas se encontraban en el segundo trimestre de embarazo. De todas las participantes, un 38,7% se encontraba en riesgo de sífilis congénita. Discusión: En total, un 23% de las participantes presentó un falso positivo biológico, cifra similar a la reportada en otros estudios. En este estudio encontramos que, en gestantes extranjeras, había mayor proporción de diagnóstico tardío en que chilenas. Esto podría deberse a dificultades para ingresar a la atención en salud. Conclusión: Pese a que en Chile contamos con buenas tasas de diagnóstico, el manejo de la sífilis gestacional podría ser mejorado con una detección y tratamiento temprano. Las extranjeras buscaron atención en salud más tarde que las chilenas, por lo tanto, recibieron tratamiento más tardío y con mayor riesgo de sífilis congénita. Esto se puede explicar por dificultades para ingresar al sistema de salud.


Introduction: Syphilis in pregnancy remains a global public health problem with severe outcomes if it is not treated properly. The Chilean Ministry of Health has established syphilis screening at three times during pregnancy, with a final retest is during labor. An adequate treatment can prevent all side effects of syphilis in pregnancy. Methods: This was a descriptive, transversal study which included 406 pregnant women who consulted for potential syphilis at the Control and Treatment of Sexual Health Unit (UNACESS in Spanish) of San José Hospital (HSJ) in Santiago, Chile from 2010 to 2016.Results: A 87,7% of the pregnant women were Chilean, while 12,3% had a different nationality. Among immigrants, the most frequent nationalities were: peruvian 54% and Haitian 18%. At enrol-ment, 47,5% of the pregnant women were in their second trimester. 38,4% was at risk of congenital syphilis.Discussion: Overall, 23,1% of the participants had a false positive test, which is congruent with pre-viously reported data. In this study, we found a higher rate of late diagnosis, mainly in the immigrant pregnant women, which could be due to difficulties in accessing healthcare and cultural matters. Conclusion: Despite a high overall treatment rate, antenatal syphilis management in this population could be improved by earlier detection and treatment. Immigrant women sought attention later in pregnancy, thus receiving delayed treatment with higher risk of congenital syphilis. This could be explained by obstacles in their access to healthcare.


Subject(s)
Humans , Female , Pregnancy , Adolescent , Adult , Pregnancy Complications, Infectious/diagnosis , Syphilis, Congenital/diagnosis , Syphilis/diagnosis , Pregnancy Complications, Infectious/epidemiology , Syphilis, Congenital/epidemiology , Syphilis/transmission , Syphilis/epidemiology , Chile , Mass Screening , Cross-Sectional Studies , Retrospective Studies , Age Distribution , Infectious Disease Transmission, Vertical/statistics & numerical data , False Positive Reactions , Emigrants and Immigrants/statistics & numerical data , Hospitals, Public
14.
Braz. oral res. (Online) ; 33: e007, 2019. tab
Article in English | LILACS | ID: biblio-989471

ABSTRACT

Abstract The aim of this study was to assess self-reported history of root canal treatment (SRHRCT) as a method for detecting the presence of root canal treatment (RCT) and apical periodontitis (AP) in a southern Brazilian subpopulation. In this cross-sectional study, 136 military police officers from the city of Porto Alegre, Brazil, were included. The participants were interviewed and full-mouth periapical radiographs were taken. A calibrated examiner determined the presence of RCT and AP by applying standardized criteria. The diagnostic accuracy of SRHRCT was calculated separately for RCT and AP. Accuracy, sensitivity, specificity, positive and negative predictive values (+PV and -PV), efficiency, and positive and negative likelihood ratios (+LR and -LR) were estimated. The mean age of the participants was 34.1 ± 10.4 years and 88.2% were males. Overall, SRHRCT demonstrated high sensitivity and specificity for RCT, but not for AP: sensitivity (RCT = 0.960, AP = 0.757) and specificity (RCT = 0.835, AP = 0.631). The estimated values for PV and LR were: +PV (RCT=0.777, AP=0.396), -PV (RCT = 0.972, AP = 0.890), +LR (RCT = 5.853, AP = 2.057), and -LR (RCT = 0.046, AP = 0.383). SRHRCT proved to be a good predictor of the presence of RCT, but a weak predictor of AP in this subpopulation.


Subject(s)
Humans , Male , Female , Adult , Periapical Periodontitis/epidemiology , Root Canal Therapy/statistics & numerical data , Self Report/standards , Periapical Periodontitis/diagnostic imaging , Reference Values , Brazil/epidemiology , Radiography, Dental , Prevalence , Cross-Sectional Studies , Reproducibility of Results , Sensitivity and Specificity , False Negative Reactions , False Positive Reactions , Middle Aged
16.
Rev. chil. endocrinol. diabetes ; 11(3): 103-107, jul. 2018. tab, ilus
Article in Spanish | LILACS | ID: biblio-915200

ABSTRACT

Abstract: Thyroid function is assessed by measuring thyrotropin and free and total thyroid hormone concentrations. There are interferences with the results of immunoassays that can lead to an incorrect diagnosis, of which the most frequent are the binding of thyroid hormones to heterophile antibodies, rheumatoid factor, anti-Ruthenium antibodies, the intake of biotin and anti-streptavidin antibodies. We present three cases of clinically euthyroid patients, with normal TSH, high free T4 and T3, and normal total T4 and T3 performed in a Roche Diagnostics ® COBAS 8000 device. When the test was repeated on a Siemens® Immulite device, the free and total hormones were within normal ranges. In the Roche Diagnostics ® assay, the presence of biotin or anti-Ruthenium or anti-streptavidin antibodies interferes with the formation of the complex responsible for the emission of light that allows inferring concentrations of thyroid hormones. The Siemens test works differently since the emission of light depends on the binding of T4 to an antibody conjugated with alkaline phosphatase not participating in the process biotin, streptavidin or ruthenium so this interference is avoided. This possible interference in immunoassays should be taken into account in case clinical manifestations differ from these laboratory determinations, to avoid a diagnosis and potential inappropriate treatment.


Resumen: La función tiroidea se evalúa midiendo tirotropina y concentraciones de hormonas tiroideas libres y totales. Existen interferencias con los resultados de inmunoensayos que pueden llevar a un diagnóstico incorrecto, de ellas, las más frecuentes son la unión de hormonas tiroideas a anticuerpos heterófilos, el factor reumatoide, anticuerpos anti Rutenio, la ingesta de biotina y anticuerpos anti estreptavidina. Se presentan tres casos de pacientes clínicamente eutiroideos, con TSH normal, T4 y T3 libres elevadas, y T4 y T3 totales normales realizadas en un equipo COBAS 8000 de Roche Diagnostics®. Cuando se repitió el ensayo en un equipo Immulite de Siemens®, las hormonas libres y totales estaban dentro de rangos normales. En el ensayo de Roche Diagnostics ®, la presencia de biotina o anticuerpos anti Rutenio o anti estreptavidina, interfiere con la formación del complejo responsable de la emisión de luz que permite inferir las concentraciones de las hormonas tiroideas. El ensayo de Siemens funciona de manera diferente ya que la emisión de luz depende de la unión de la T4 a un anticuerpo conjugado con fosfatasa alcalina no participando en el proceso biotina, estreptavidina o Rutenio por lo que se evita esta interferencia. Esta posible interferencia en inmunoensayos debe ser tenida en cuenta en caso de que las manifestaciones clínicas difieran de estas determinaciones de laboratorio, para evitar un diagnóstico y potencial tratamiento inadecuado.


Subject(s)
Humans , Female , Adult , Middle Aged , Thyroid Hormones/immunology , Thyroid Hormones/blood , Immunoassay/methods , Thyrotropin/immunology , Thyrotropin/blood , False Positive Reactions
17.
Rev. Soc. Bras. Med. Trop ; 51(3): 387-389, Apr.-June 2018. tab, graf
Article in English | LILACS | ID: biblio-1041461

ABSTRACT

Abstract INTRODUCTION: Several factors can cause false-positive results in the galactomannan (GM) test; however, others remain unknown. Presently, the impact of airborne contamination by Aspergillus conidia during enzyme-linked immunosorbent assay (ELISA) remains uninvestigated. METHODS: We studied 12 A. fumigatus isolates. Fungal conidia were serially diluted and tested for GM detection using the Platelia® Aspergillus enzyme immunoassay (EIA). RESULTS: The conidia concentration required for an EIA-positive result was 4.8 × 103 (median). CONCLUSIONS: This is the first study to evaluate the impact of environmental contamination on the Platelia® Aspergillus EIA assay. Only massive contamination can interfere with GM optical readings, suggesting that environmental contamination does not cause false-positive test results.


Subject(s)
Humans , Aspergillus fumigatus/isolation & purification , Spores, Fungal , Enzyme-Linked Immunosorbent Assay/adverse effects , False Positive Reactions , Mannans , Enzyme-Linked Immunosorbent Assay/methods
18.
Rev. Asoc. Méd. Argent ; 130(4): 4-10, dic. 2017. tab, ilus
Article in Spanish | LILACS | ID: biblio-973085

ABSTRACT

El método gold standar para el diagnóstico de la tuberculosis (TB) es el cultivo en medio sólido de Lowenstein-Jensen. Dado el alto costo y los requerimientos de infraestructura y personal entrenado que exige este método, tanto el programa nacional, como las recomendaciones de la Organización Mundial de la Salud (OMS), establecen que una baciloscopía positiva (BAAR +) confirma el diagnóstico de TB. Si bien el cultivo amplía la sensibilidad diagnóstica, tipifica los bacilos, y permite realizar pruebas de sensibilidad, no es un requisito operativo para la definición de confirmación bacteriológica de TB. En Argentina, el 1% de las BAAR (+) corresponden a otras etiologías3. Presentamos un caso comprendido en ese 1%, en el cual mostramos los problemas a los que se enfrenta un paciente (fundamentalmente demora diagnóstica y exposición innecesaria a drogas potencialmente tóxicas) cuando tiene un diagnóstico de TB de acuerdo con los stándares nacionales e internacionales y sin embargo no es TB.


The method gold standard for the diagnosis of tuberculosis (TB) is the culture in Lowenstein-Jensen’s solid way. In view of the high cost and the requirements of infrastructure and trained personnel that demands this method, both the national program, and the recommendations of the World Health Organization (WHO), they establish that a smear-positive confirms TB’s diagnosis. In addition, the culture increases the diagnostic sensitivity, typifies the bacillus and allows the sensitivity tests to be performed, but it is not an operative requirement for the definition of TB’s bacteriological confirmation. In Argentina, 1% of the BAAR (+) are due to other etiologies3. We present a case included in that 1%, in which we show the problems that a patient faces (basically diagnostic delay and unnecessary exposure to potentially toxic drugs) when it has TB’s diagnosis of agreement to the national and international standards and nevertheless it is not TB.


Subject(s)
Male , Humans , Middle Aged , Nontuberculous Mycobacteria/isolation & purification , Bacteriological Techniques , Tuberculosis, Pulmonary/microbiology , Tuberculosis, Pulmonary/diagnosis , Mycobacterium Infections, Nontuberculous/microbiology , Mycobacterium Infections, Nontuberculous/diagnosis , Tuberculosis, Pulmonary/diagnostic imaging , Radiography, Thoracic , False Positive Reactions , Mycobacterium Infections, Nontuberculous/drug therapy , Tomography, X-Ray Computed , Sputum/microbiology
19.
Electron. j. biotechnol ; 28: 20-26, July. 2017. tab, graf
Article in English | LILACS | ID: biblio-1015729

ABSTRACT

Background: Infectious Pancreatic Necrosis Virus (IPNV) is the etiological agent of a highly contagious disease that affects salmonids. In Chile, the second worldwide salmon producer, IPNV causes great economic loss and is one of the most frequently detected pathogens. Due to its high level of persistence and the lack of information about the efficiency of its diagnostic techniques, the National Reference Laboratory (NRL) for IPNV in Chile performed the first inter-laboratory ring trial, to evaluate the sensitivity, specificity and repeatability of the qRT-PCR detection methods used in the country. Results: Results showed 100% in sensitivity and specificity in most of the laboratories. Only three of the twelve participant laboratories presented problems in sensitivity and one in specificity. Problems in specificity (false positives) were most likely caused by cross contamination of the samples, while errors in sensitivity (false negatives) were due to detection problems of the least concentrated viral sample. Regarding repeatability, many of the laboratories presented great dispersion of the results (Ct values) for replicate samples over the three days of the trial. Moreover, large differences in the Ct values for each sample were detected among all the laboratories. Conclusions: Overall, the ring trial showed high values of sensitivity and specificity, with some problems of repeatability and inter-laboratory variability. This last issue needs to be addressed in order to allow harmonized diagnostic of IPNV within the country. We recommend the use of the NRL methods as validated and reliable qRT-PCR protocols for the detection of IPNV.


Subject(s)
Animals , Salmonidae/virology , Infectious pancreatic necrosis virus/isolation & purification , Birnaviridae Infections/diagnosis , Reverse Transcriptase Polymerase Chain Reaction/standards , Real-Time Polymerase Chain Reaction/standards , Fish Diseases/diagnosis , RNA, Viral/genetics , Observer Variation , Chile , Sensitivity and Specificity , Infectious pancreatic necrosis virus/genetics , Birnaviridae Infections/virology , Aquaculture , False Negative Reactions , False Positive Reactions , Fish Diseases/virology , Laboratories
20.
Med. leg. Costa Rica ; 34(1): 73-79, ene.-mar. 2017. tab, ilus
Article in Spanish | LILACS | ID: biblio-841428

ABSTRACT

Resumen:El carcinoma de mama representó el tumor en mujeres más frecuente en Costa Rica para el año 2013. La disección axilar en el cáncer de mama es una de las causas de mayor comorbilidad en las pacientes. La realización de un ganglio centinela para determinar si es necesario la disección axilar, ha resultado de gran ayuda, reduciendo las comorbilidades en las pacientes con cáncer de mama. La experiencia del cirujano en la realización de procedimiento y del patólogo, han reducido los falsos negativos en los ganglios centinelas por congelación hasta en un 4.5%.En este estudio se analizaron los ganglios centinelas por congelación que contaban con biopsia definitiva y se determinó que los falsos negativos para nuestro hospital eran del 1.2%, además en estos casos, se determinó la media de tipo histológico, el grado histológico y el tamaño del cáncer de mama. En conclusión, se determinó que una de las casusas principales asociadas a los falsos negativos es la presencia de tejido adiposo en el ganglio centinela.


AbstractBreast carcinoma represented de most frequent tumor in Costa Rica during 2013. The axillary dissection in pacients with breast cancer is one of the causes of the most frecuent comorbidity. Studying sentinel ganglion to decide if it is necesary to make an axillary dissection has become very useful in reducing comorbidity in pacients with breast cancer. The surgeon´s and de pathologist´s work experience with this procedure has reduced false positive results in the sentinel ganglion´s biopsies by frezzing method in 4,5%. During the current report the sentinel ganglions by freezing method that had a definite biopsy were studied and we arrived to the conclusion that for our hospital falsepositives were less than 1,2%. As well in this cases it was determined the histologic type, the histologic grade and the size of the breast cancer. In conclusion it was determined that one of the most frecuent causes associated with false positives is the presence of adipose tissue in the sentinel ganglion.


Subject(s)
Humans , Breast Neoplasms , Costa Rica , Sentinel Lymph Node Biopsy , False Positive Reactions , Sentinel Lymph Node , Lymph Node Excision
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