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Biochem Med (Zagreb) ; 29(2): 021001, 2019 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-31223267


Introduction: Measurement of high-sensitivity troponin T (hs-TnT) has become an essential step in the diagnosis of acute myocardial infarction. This high-sensitivity method allows quantifying the concentration of troponin T in blood of healthy subjects with a lower inaccuracy compared to previous reagent generations. However, the presence of certain compounds in the sample may interfere with the result. We present a patient who had repeatedly high concentrations of hs-TnT in the serum sample that did not agreed with the signs and symptoms. In addition, ultrasensitive troponin I concentration was undetectable. Materials and methods: To investigate the presence of an interfering compound, different analysis were carried out. In order to discard macro complexes in the sample, the serum was precipitated with polyethylene glycol. In addition, the serum was incubated with Scantibodies Heterophilic Blocking Tube, which can block heterophilic antibodies. Finally, a size exclusion chromatography of the sample was performed by the manufacturer. What happened: The interfering substance was allocated into fractions with proteins of 150kDa, corresponding to high molecular weight proteins like immunoglobulin G (IgG). This compound was responsible for the falsely elevated hs-TnT results and it affected only the high-sensitivity methods. Main lesson: The detected interfering compound was probably an IgG. This type of interference must be kept in mind in front of discordant results, even if they are extremely rare. Therefore, interdisciplinary cooperation between clinicians, laboratory and manufacturer is essential.

Troponina T/sangue , Criança , Humanos , Masculino , Polietilenoglicóis/química , Sensibilidade e Especificidade
Rev. lab. clín ; 12(2): 93-97, abr.-jun. 2019. graf
Artigo em Espanhol | IBECS-Express | ID: ibc-ET1-4160


Los intervalos de referencia biológicos no proporcionan información suficiente para la interpretación de un cambio entre dos valores medidos consecutivos debido a que, para la gran mayoría de las magnitudes, la variabilidad biológica intraindividual es menor que la variabilidad biológica interindividual. Teniendo en cuenta esta situación, el laboratorio podría proporcionar, conjuntamente con los intervalos de referencia, información adicional que permita estimar de manera objetiva la significación de un cambio en los valores de una magnitud biológica para un mismo individuo. En este sentido, la manera más adecuada para interpretar un cambio debe realizarse en función del concepto de incertidumbre, ya que permite considerar todas las posibles fuentes de variación a las que están sometidos los valores medidos. Este documento, basado en guías de ámbito nacional e internacional se describe un procedimiento para la interpretación de un cambio entre dos valores consecutivos de una magnitud biológica, basado en el estudio de las diversas fuentes de incertidumbre que le afectan

Biological reference intervals do not provide sufficient information for the interpretation of a change between two consecutive measured values of a biological quantity because, for the vast majority of quantities, the intra-individual biological variability is smaller than the inter-individual biological variability. Taking into account this situation, the laboratory could provide, in conjunction with the reference intervals, additional information to objectively estimate the significance of a change in the values of a biological quantity. In this sense, the most adequate way to interpret the change must be made on the basis of the uncertainty concept, since it allows taking into account all the possible sources of variation to which the measured values are subjected. This document, based on national and international guidelines, describes a procedure for the interpretation of a change between two consecutive values of a biological quantity, based on the study of the various sources of uncertainty that affect it

Biochem Med (Zagreb) ; 29(1): 010704, 2019 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-30591814


Introduction: The aim of this study was to analyse critical value data from our laboratory and compare our critical value reporting policy with others in the literature. Materials and methods: Analysis of critical values was performed on data obtained over a 6-month period in a tertiary university hospital. Results: We identified 5723 critical values, of which approximately 80% came from STAT testing (4577), 15% from routine inpatients testing (884) and 5% from routine outpatients testing (262). The highest proportion of critical values corresponded to oxygen partial pressure (17.7%), followed by potassium ion (17.6%) concentrations. The parameters associated with the highest critical value notification percentage in emergency patients were pH, haematocrit, glucose, potassium ion and haemoglobin concentrations. In inpatients, these parameters were glucose, phosphate, haemoglobin, sodium ion and potassium ion concentrations. In outpatients, they were calcium and potassium concentrations. Conclusions: The analysis of critical values in our hospital is in accordance with that reported in the literature. Our findings demonstrate the importance of incorporating improvement actions not only in critical value notification, but especially in the registration of this activity.

Hospitais Universitários , Laboratórios Hospitalares , Valores Críticos Laboratoriais , Centros de Atenção Terciária , Plaquetas/química , Cálcio/sangue , Eritrócitos/química , Glucose/análise , Hemoglobinas/análise , Humanos , Fosfatos/sangue , Potássio/sangue , Sódio/sangue , Espanha
J Clin Lab Anal ; 32(8): e22566, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29732606


BACKGROUND: Patients with dyslipidemia are often treated with statins to reduce lipids and hence cardiovascular risk, but treatment response is variable, partly due to genetic factors. METHODS: We studied the influence of 6 gene variants (APOE c.526C > T (APOE2), APOE c.388T > C (APOE4), SLCO1B1 c.521T > C, CYP3A4 c.-392G > A, HMGCR c.1564-106A > G, and LPA c.3947 + 467T > C) on statin efficacy assessing 2 indicators: the percent reduction in total cholesterol (TC) and non-HDL cholesterol (non-HDL), as well as the achievement of therapeutic goals. The study was performed in a group of patients (n = 100) without previous pharmacological treatment. Multiple regression models were used to calculate the percentage of explanation in response variability added by every variant to a basal model constructed with significant nongenetic control variables. RESULTS: The most influential variant was HMGCR c.1564-106A > G (rs3846662), and carriers showed a significantly lower reduction in TC and non-HDL. This variant is related to an alternative splicing involving exon 13, which is also regulated by lipid concentrations in patients without the variant. Concerning therapeutic goals, HMGCR c.1564-106A > G hindered the achievement of TC targets on patients. CONCLUSIONS: The HMGCR c.1564-106A > G variant was associated with less statin efficacy to decrease cholesterol.

Colesterol/sangue , Dislipidemias/tratamento farmacológico , Dislipidemias/genética , Hidroximetilglutaril-CoA Redutases/genética , Inibidores de Hidroximetilglutaril-CoA Redutases/uso terapêutico , Polimorfismo de Nucleotídeo Único/genética , Adulto , Dislipidemias/sangue , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Análise de Regressão , Resultado do Tratamento
Cytometry B Clin Cytom ; 94(5): 680-688, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-28834596


BACKGROUND: Hematological cytometers with a biological fluid module could potentially correct the limitations of the manual chamber method. This study evaluates the agreement between the manual technique and the Sysmex XN-1000 analyzer for white blood cell (WBC) and red blood cell (RBC) counts, as well as for leukocyte differentiation in different types of fluids. This study also evaluates the advantages of incorporating the technique in routine laboratory work. METHODS: One hundred and three fluid samples examined were 45 ascite (AF), 21 synovial (SF), 33 pleural (PF), and 31 cerebrospinal (CSF) fluid samples. All cell counting was performed with a Sysmex XN-1000 and a Fuchs-Rosenthal counting chamber. May Gründwald-Giemsa stain was used for manual WBC differentiation. The manual analysis data were obtained in duplicate by the same two observers. Passing-Bablok regression and the Kappa index were used to evaluate the interchangeability and concordance. RESULTS: Good agreement was observed for WBC differentiation in all fluids and for WBC counts in SF and PF. An optimal Kappa index was obtained, which indicated agreement and clinical significance for WBC and RBC counts in CSF and for RBC counts in PF. There was disagreement for WBC and RBC analysis in AF, with significantly higher results from the Sysmex XN-1000 than from the manual method. A reduction in laboratory response time was observed when using the automatic method. CONCLUSIONS: Except for AF, the Sysmex XN-1000 results agree with those of the manual method, although to different degrees depending on the fluid type. © 2017 International Clinical Cytometry Society.

Automação , Líquidos Corporais/química , Testes Hematológicos/instrumentação , Leucócitos/patologia , Contagem de Células Sanguíneas , Diferenciação Celular , Humanos
Clin Chem Lab Med ; 50(1): 31-4, 2011 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-21942895


To date not much importance has been given to the sorting of examined properties ("tests") in clinical laboratory reports. The present article contains a proposal about sorting the examined properties of clinical laboratory reports, in order to facilitate their interpretation to the requesting physicians. This proposal is mainly based on clinical and patho-physiological criteria. A set of groups of properties has been established according to the main clinical indications of each property. Some of these properties have several clinical indications and, consequently, have been included in more than one group. Some of these groups have been associated to other groups, so that the properties conforming them will always appear consecutively, since they are patho-physiologically related. Finally, an association between each group with the different medical specialities or areas of knowledge has been made, according to the clinical indications of each property. The groups of properties proposed are in concordance with their main clinical indications and their patho-physiological relationship. This ordering system gives priority, first, to the alarm (critical) values and, second, to the medical speciality or knowledge area of the requesting physician. This proposal can help the requesting physician to see first of all the most relevant clinical laboratory information related to her/his patient.

Química Clínica/métodos , Química Clínica/normas , Relatório de Pesquisa/normas , Alergia e Imunologia , Bioquímica , Humanos , Microbiologia
Rev. lab. clín ; 4(2): 84-89, abr.-jun. 2011.
Artigo em Espanhol | IBECS | ID: ibc-88076


La medida en suero de la concentración de tirotropina y tiroxina es la base para la evaluación bioquímica de la función tiroidea. Con frecuencia, el intervalo de referencia de la tirotropina sirve como cribado inicial para valorar la necesidad de añadir la medida de tiroxina. Este trabajo se ha realizado con el objetivo de mejorar la sensibilidad diagnóstica del cribado. Se seleccionaron todos los resultados de tirotropina y tiroxina solicitados de manera simultánea a pacientes de consultas externas: para la primera parte del estudio se usaron los del año 2008 (n=10.900) y para la segunda parte, los de pacientes del año 2009 sin seguimiento en el año previo (n=5.367). Se realizaron dos curvas ROC para delimitar el intervalo de decisión del algoritmo con una sensibilidad del 90% y se contabilizó el número de resultados falsos negativos obtenidos. Los intervalos de tirotropina obtenidos en el primer y segundo estudio fueron (2,11-3,50) mint.u./L y (2,04-3,41) mint.u/L respectivamente. En ambos estudios la sensibilidad aumentó aproximadamente de un 70% de media con el intervalo de referencia a un 90% con el intervalo del algoritmo. El número de falsos negativos se redujo de 75 a 30 en el primer caso, y de 37 a 13 en el segundo. La aplicación de un intervalo de tirotropina calculado para la evaluación de la función tiroidea, en pacientes ambulatorios con o sin seguimiento previo, supone un aumento en la sensibilidad diagnóstica, respecto al empleo del intervalo de referencia de tirotropina (AU)

The measurement of thyrotropin and thyroxine concentrations in serum is the basis of the biochemical evaluation of thyroid function. The reference interval of thyrotropin is frequently used as an initial screening to assess the need for thyroxine measurement. This study was carried out to obtain a different and more adjusted interval of thyrotropin, in order to improve the diagnostic sensitivity. All of the results of thyrotropin and thyroxine requested at the same time on outpatients were selected: for the first part of the study, those from year 2008 (n=10,900), and for the second part, those from 2009 with no follow-up in the previous year (n=5,367). Two ROC curves were used to define the algorithm decision interval with a sensitivity of 90% and the number of false negative results was calculated. The thyrotropin intervals obtained in the first and second studies were (2.11-3.50) mIU/L and (2.04-3.41) mIU/L, respectively. In both studies, the sensitivity increased approximately from an average of 70% to 90% of the confidence interval using the algorithm interval. The number of false negatives was reduced from 75 to 30 in the first case, and from 37 to 13 in the second case. The application of a calculated thyrotropin interval to assess thyroid function in outpatients with or without prior monitoring, leads to an increase of the diagnostic sensitivity with regard to the use of the thyrotropin reference interval (AU)

Humanos , Masculino , Feminino , Sensibilidade e Especificidade , Testes de Função Tireóidea/métodos , Testes de Função Tireóidea , Programas de Rastreamento/métodos , Testes de Função Tireóidea/tendências , Receptores da Tireotropina/análise , Tireotropina/análise , Tiroxina/análise , Tiroxina , Curva ROC