Análisis del nivel de desempeño de indicadores preanalíticos en las áreas de química clínica y hematología del Laboratorio del Hospital Distrital Inmaculada Concepción de Caaguazú, Paraguay / Analysis of the performance level of pre-analytical indicators in the areas of clinical chemistry and hematology at the Laboratory of the Inmaculada Concepción District Hospital in Caaguazú, Paraguay

Introducción. La fase pre-analítica es un componente esencial en el algoritmo de análisis clínicos, que conlleva una serie de pasos y procedimientos. Objetivo. Describir el nivel de cumplimiento de los indicadores preanalíticos en las áreas de química y hematología del laboratorio clínico del Hospital Distrital Inmaculada Concepción. Materiales y método. Se aplicó un diseño no experimental con un enfoque mixto de corte transversal y alcance descriptivo. Se incluyeron tres bioquímicos y cien pacientes mediante un muestreo por conveniencia. Los datos fueron obtenidos por observación estructurada a pacientes y entrevista semiestructurada a los funcionarios del hospital. Resultados. El nivel de desempeño de los bioquímicos con relación a los indicadores preanalíticos presenta aspectos tanto positivos como negativos, de los cuales resalta el aspecto positivo en un 61% y el 39% corresponde a aspectos considerados como deficientes. Las dificultades existentes son la identificación correcta del paciente y la comunicación entre el médico tratante y/o técnico con ellos, los cuales en su gran mayoría no tienen conocimiento de las condiciones en las cuales deben presentarse para un examen médico. Conclusión. La adecuada realización de las acciones correctas, como la calidad de las mismas, en la fase pre-analítica se relaciona de manera directa con los resultados que se obtienen, que luego serán utilizados por los profesionales solicitantes para toma de decisiones, por lo que es un eslabón inicial que afecta a todo el proceso posterior. Palabras clave: calidad de atención en salud; laboratorio; fase preanalítica

Introduction. The pre-analytical phase is a vital component of the clinical analysis algorithm. This involves a series of steps and procedures. Objective. To describe the level of compliance with the preanalytical indicators in the areas of chemistry and haematology ofthe clinical laboratory at a local Hospital in Caaguazú. Materiales y método. Anon-experimental design and a mixed cross-sectional approach were applied. Three biochemists and one hundred patients were includer. Results. Our data was obtained by structured observation to patients and semi-structured interviews tothree biochemists. The level of performance of the biochemists about the pre-analytical indicators presents both positive and negative aspects, of which the positive aspect stands out in 61% and 39% corresponds to aspects considered as deficient. The existing difficulties are the correct identification of the patient and the communication between the treating physician and/or technician, most of whom are unaware ofthe conditions in which they should present themselves for a medical examination. Conclusion. The correct performance, as well as their quality, in the pre-analytical phase, is directly related to the results obtained, which the requesting professionals will later use for decision-making, so it is an initial link that affects the entire subsequent process and must always be considered essential. Keywords: quality of health care; laboratories; pre-analytical phase

Estrategias para la reconversión del ejercicio profesional: Proyecto Bioquímico Nexo / Strategies for the reconversion of professional practice: Biochemical Nexus Project

El avance de la ciencia y la tecnología en el área de la bioquímica clínica ha ocasionado la necesidad de reflexionar acerca de una reingeniería de la práctica profesional. El proceso diagnóstico es complejo y dinámico, requiere del trabajo interdisciplinario y de la comunicación efectiva, además de un cambio en el accionar profesional, con el eje centrado en el paciente y en un laboratorio "a puertas abiertas". En este marco se planteó el Proyecto Bioquímico Nexo (BN) con el propósito de lograr las competencias y habilidades necesarias para formar profesionales bioquímicos clínicos integrales que puedan cumplir con este nuevo rol sobre la base de una construcción colectiva de los saberes (AU)

Advances in science and technology in the area of clinical biochemistry have prompted the need to reflect on the reengineering of professional practice. The diagnostic process is complex and dynamic, requiring interdisciplinary work and effective communication, as well as a change in professional action, with the focus on the patient and an "open-door" laboratory. Within this framework, the Biochemical Nexus Project (BN) was proposed with the purpose of achieving the competencies and skills necessary to comprehensively train clinical biochemists who can fulfill this new role based on a collective construction of knowledge (AU)

Tomar mate previo a la flebotomía no interfiere en las pruebas bioquímicas de rutina / Drinking mate prior to phlebotomy does not interfere with routine biochemical tests

En este estudio se evaluó el efecto de tomar mate en las pruebas bioquímicas de rutina. Se extrajo sangre a 32 mujeres voluntarias luego de 12 horas de ayuno y a la hora (T1), dos horas (T2) y tres horas (T3) posteriores a la toma de 5 mates. Se estudiaron parámetros hematológicos y analitos de química clínica. Los resultados se analizaron empleando pruebas estadísticas para muestras relacionadas. Se calculó la diferencia porcentual media (DM%) de cada analito en cada hora respecto del valor basal y se comparó con el valor de referencia del cambio (VRC). Una DM% mayor que el VRC se consideró clínicamente significativa. En T1, T2 y T3 los recuentos de neutrófilos, eosinófilos y linfocitos fueron más bajos que en T0, también los niveles de glucosa, urea, creatinina y cistatina C fueron más bajos que en T0, mientras que los valores de proteínas totales, colesterol transportado por lipoproteínas de baja densidad y la actividad enzimática de lactato deshidrogenasa fueron más altos que en T0. En todos los casos los cambios fueron estadísticamente significativos, aunque no lo fueron desde el punto de vista clínico. Tomar 5 mates antes de la flebotomía no interfiere en los resultados de las pruebas bioquímicas de rutina.

In the present study the effect of drinking mate in routine biochemical tests was evaluated. Blood was collected from 32 female volunteers after a 12 h fasting period. In addition, 1 hour (T1), 2 hours (T2), and 3 hours (T3) after drinking 5 mates, blood was collected again. Hematological parameters and clinical chemistry analytes were studied. The results were analyzed using statistical tests for related samples. Mean difference % (MD%) was calculated for each analyte and was further compared with reference change value (RCV). The MDs% higher than RCV were considered clinically significant. At T1, T2, and T3 the count neutrophils, eosinophils and lymphocytes were lower than at T0. Also glucose, urea, creatinine, and cystatin C values were lower than at T0 whereas total proteins, LDL-C, and LD enzymatic activity values were higher than at T0. In all cases, variability was statistically significant but not clinically significant. Drinking 5 mates prior to phlebotomy does not interfere with the results of routine biochemical tests.

Neste trabalho, o efeito de beber chimarrão foi avaliado em testes bioquímicos de rotina. O sangue foi extraído de 32 mulheres voluntárias após 12 horas de jejum, e uma hora (T1), duas horas (T2) e três horas (T3) após a tomada de 5 chimarrões. Parâmetros hematológicos e analitos de química clínica foram estudados. Os resultados foram analisados utilizando testes estatísticos para amostras relacionadas. A diferença percentual média% (DM%) de cada analito em cada hora foi calculada em relação ao valor basal e comparada com o valor de referência da modificação (VRM). Uma DM% maior que o VRM foi considerada clinicamente significativa. Em T1, T2 e T3 as contagens de neutrófilos, eosinófilos e linfócitos foram mais baixas que em T0, Também os níveis de glicose, ureia, creatinina e cistatina C foram mais baixos que em T0, ao passo que os valores de proteínas totais, colesterol transportado por lipoproteínas de baixa densidade e a atividade enzimática de lactato desidrogenase foram mais altos que em T0. Em todos os casos as alterações foram estatisticamente significativas, embora do ponto de vista clínico não o tenham sido. Tomar 5 chimarrões antes da flebotomia não interfere nos resultados dos testes bioquímicos de rotina.

EQA-based evaluation of metrological traceability of clinical chemistry test results in Argentina / EQA-based evaluation of metrological traceability of clinical chemistry test results in Argentina

Equivalence of results among laboratories is a major mission for medical laboratories. In the Netherlands, medical laboratories only use homogenous, commercial for general chemistry analytes, whereas in Argentina heterogenous, home brew test applications are common. The effect of this practice difference on test accuracy is studied using key features of the accuracy-based EQA program of the Netherlands. Six frozen, human-based, commutable poolsera, covering the (patho) physiological measuring range for 17 general chemistry analytes, were assayed by ~75 Argentinian labs and ~200 Dutch laboratories in 2014. After removal of outliers, harmonization status among laboratories was evaluated by calculating overall mean interlaboratory coefficients of variation (CVs, %) per analyte and per country for all 6 levels. Evenso, standardization status was evaluated after removal of outliers by calculating overall mean recoveries (%) as compared to the assigned target values per analyte per country for all 6 levels. Absolute median biases were compared to (minimal/desirable) biases derived from biological variation criteria. For serum enzymes interlaboratory CVs in the Argentinian laboratories ranged between 10 and 22%, as compared to 3-6% in the Netherlands. For serum uric acid, creatinine, glucose and total protein, interlaboratory CVs varied between 4.3 and 13.1% in Argentinian labs, as compared to <3.5% in the Netherlands. For serum electrolytes, interlaboratory CVs ranged between 1.8 and 3.8% for Na+; 2.9-5.8% for Cl-; 3.8-7.5% for K+; 9.4-10.4% for Ca2+ and 16.2-22.3% for Mg2+ as compared to ≤2% (Na+, K+, Cl-, Ca2+) and ≤3% (Mg2+) in the Netherlands. Mean recoveries in Argentinian laboratories for e.g. serum creatinine, glucose, CK, Ca2+ and Na+ were 95-119%; 95-104%; 98-102%; 98-102% and 96-100% respectively, whereas min-max recovery ranges were 65-155%; 58-126%; 47-132%; 66-132% and 85-115%. In the Netherlands, absolute mean recoveries were overall 98.9% with a SD of 2.0%. Median biases in Argentinian laboratories ranged from -2.9 to 18.2%; -3.1 - 2.6%; -3.3 - 0.5%; -1.1 - 3.8% and -4.3-0% for serum creatinine, glucose, CK, Ca2+ and Na+. In the Netherlands overall mean/median biases were 1.1% (SD=2.0%). Exchange of commutable, value- assigned EQA-materials was helpful for studying the harmonization and standardization status of medical tests in Argentina, and for revealing the future harmonization and standardization potential. The results clearly demonstrate that metrological traceability of test results in Argentina is on average in line with what is expected; yet, the spreading among laboratories is far too high and should be improved.

La equivalencia de resultados entre laboratorios es una mision importante para los laboratorios medicos. En los Paises Bajos, los laboratorios medicos solo usan aplicaciones comerciales homogeneas, regulatoriamente aprobadas (CE-IVD) para analitos quimicos, mientras que en la Argentina son comunes las aplicaciones heterogeneas caseras. El efecto de esta diferencia practica en la precision de la prueba se estudia utilizando caracteristicas clave del programa EQA, basado en la precision, de los Paises Bajos. Se ensayaron seis pools de sueros, congelados, de origen humano, conmutables, que cubrian el rango de medidas (pato)fisiologicas para 17 analitos de quimica clinica. Estos analitos de quimica clinica fueron analizados por ~75 laboratorios argentinos y ~200 laboratorios holandeses en 2014. Despues de eliminar los valores atipicos, el estado de armonizacion entre los laboratorios fue evaluado calculando los coeficientes de variacion interlaboratorios medios globales (CV%) por analito y por pais para los 6 niveles. No obstante, el estado de estandarizacion se evaluo despues de la eliminacion de valores atipicos mediante el calculo de recuperaciones medias generales (%) en comparacion con los valores asignados por analito por pais para los 6 niveles. Los sesgos medios absolutos se compararon con los sesgos (minimos / deseables) derivados de los criterios de variacion biologica. Para enzimas sericas los CV interlaboratorio en los laboratorios argentinos oscilaron entre 10 y 22%, en comparacion con 3-6% en los Paises Bajos. Para el acido urico serico, creatinina, glucosa y proteinas totales, los CV entre laboratorios variaron entre 4,3 y 13,1% en los laboratorios argentinos, en comparacion con <3,5% en los Paises Bajos. Para los electrolitos sericos, los CV interlaboratorios oscilaron entre 1,8 y 3,8% para Na+; 2,9-5,8% para Cl-; 3,8-7,5% para K+; 9,4-10,4% para Ca2+ y 16,2-22,3% para Mg2+ en comparacion a ≤2% (Na+, K+, Cl-, Ca2+) y ≤3% (Mg2+) en los Paises Bajos. Las recuperaciones medias en laboratorios argentinos para, p.ej. la creatinina serica, glucosa, CK, Ca2+ y Na+ fueron 95-119%; 95-104%; 98-102%; 98-102% y 96-100% respectivamente, mientras que los rangos de recuperacion min-max fueron 65-155%; 58-126%; 47-132%; 66-132% y 85-115%. En los Paises Bajos, las recuperaciones medias absolutas fueron en general del 98,9% con una desviacion estandar (DE) del 2,0%. La mediana de los sesgos medios de los laboratorios argentinos oscilo entre -2,9 y 18,2%; -3,1 - 2,6%; -3,3 - 0,5%; -1,1 - 3,8% y -4,3-0% para creatinina serica, glucosa, CK, Ca2+ y Na+. En los Paises Bajos, las medias / medianas en general fueron de 1,1% (DE=2,0%). El intercambio de los valores asignados a los materiales EQA, conmutables fue de gran ayuda para la armonizacion y estandarizacion de los ensayos medicos en la Argentina y para revelar el potencial futuro de armonizacion y estandarizacion. Estos resultados claramente demuestran que la trazabilidad metrologica de los resultados de las pruebas en la Argentina esta, en promedio, de acuerdo con lo esperable; sin embargo, la dispersion entre laboratorios es muy grande y deberia ser mejorada.

A equivalencia de resultados entre laboratorios e uma missao importante para os laboratorios medicos. Nos Paises Baixos, os laboratorios medicos so utilizam aplicacoes comerciais homogeneas, aprovadas por regulacoes (CE-IVD) para analitos quimicos, ao passo que na Argentina sao comuns as aplicacoes heterogeneas caseiras. O efeito desta diferenca pratica na exatidao do teste e estudado utilizando caracteristicas essenciais do programa EQA, dos Paises Baixos, baseado na exatidao. Foram ensaiados seis pools de soros, congelados, de origem humana, comutaveis, que abrangiam a faixa de medidas (pato)fisiologicas para 17 analitos quimicos gerais. Esses analitos quimicos foram analisados por ~75 laboratorios argentinos e ~200 laboratorios holandeses em 2014. Apos eliminar os valores atipicos, o estado de harmonizacao entre os laboratorios foi avaliado atraves do calculo dos coeficientes de variacao interlaboratorio meios globais (CV%) por analito e por pais para os 6 niveis. Nao obstante, o estado de padronizacao foi avaliado depois da eliminacao de valores atipicos pelo calculo de recuperacoes medias gerais (%) se comparados com os valores atribuidos por analito por pais para os 6 niveis. Os vieses medios absolutos foram comparados com os vieses (minimos / desejaveis) decorrentes dos criterios de variacao biologica. Para enzimas sericas, os CV interlaboratorio nos laboratorios argentinos oscilaram entre 10 e 22%, em comparacao com 3-6% nos Paises Baixos. Para o acido urico serico, creatinina, glicose e proteinas totais, os CV entre laboratorios variaram entre 4,3 e 13,1% nos laboratorios argentinos, em comparacao com <3,5% nos Paises Baixos para os eletrolitos sericos, os CV interlaboratorios oscilaram entre 1,8 e 3,8% para Na+; 2,9-5,8% para Cl-; 3,8-7,5% para K+; 9,4-10,4% para Ca2+ e 16,2-22,3% para Mg2+ em comparacao com ≤2% (Na+, K+, Cl-, Ca2+) e ≤3% (Mg2+) nos Paises Baixos. As recuperacoes medias em laboratorios argentinos para, p.ex. a creatinina serica, glicose, CK, Ca2+ e Na+ foram 95-119%; 95-104%; 98-102%; 98-102% e 96-100% respectivamente, enquanto que os intervalos de recuperacao min-max. foram 65-155%; 58-126%; 47-132%; 66-132% e 85-115%. Nos Paises Baixos, as recuperacoes medias absolutas foram em geral de 98,9% com um desvio padrao (DE) de 2,0%. A mediana dos vieses medios dos laboratorios argentinos oscilou entre -2,9 e 18,2%; -3,1 - 2,6%; -3,3 - 0,5%; -1,1 - 3,8% e -4,3-0% para creatinina serica, glicose, CK, Ca2+ e Na+. Nos Paises Baixos, as medias / medianas em geral foram de 1,1% (DE=2,0%). O intercambio dos valores atribuidos aos materiais EQA, comutaveis, foi de grande ajuda para a harmonizacao e padronizacao dos ensaios medicos na Argentina e para revelar o potencial futuro de harmonizacao e padronizacao. Esses resultados demonstram as claras que a rastreabilidade metrologica dos resultados dos testes na Argentina esta de acordo com o esperavel; a dispersao entre laboratorios ainda e muito grande e deveria ser melhorada.

Programa de Evaluación Externa de la Calidad "Prof. Dr. Daniel Mazziotta": una nueva etapa asegurando la mejora continua de la calidad / External Quality Assessment Program "Prof. Dr. Daniel Mazziotta ": a new stage ensuring continuous quality improvement

Las determinaciones de los laboratorios clínicos tienen un papel muy importante en la evaluación, diagnóstico, tratamiento y evolución del estado de salud de las personas. La confiabilidad de sus resultados se logra a través del aseguramiento de la calidad y mejora continua. El Programa de Evaluación Externa de la Calidad "Prof. Dr. Daniel Mazziotta" acompaña a los laboratorios de análisis clínicos desde hace 31 años brindando distintas herramientas para garantizar la calidad analítica. Ofrece los servicios de evaluación externa de la calidad, suministro de material para control de calidad interno para determinaciones en Química Clínica y soluciones para control de instrumental y pruebas de suficiencia. Desde la creación del programa se establecieron objetivos estratégicos a desarrollarse en tres etapas: establecimiento, consolidación y apoyo a la gestión de la calidad. Se genera ahora una nueva etapa, cuyo objetivo final es la acreditación. Como primer paso de este ciclo, se implementó un sistema de gestión de la calidad (SGC) de acuerdo a los requisitos establecidos en la norma argentina IRAM-ISO 9001:2015. En agosto de 2019, el Instituto Argentino de Normalización y Certificación (IRAM), representante en Argentina de la International Organization for Standarization (ISO), certificó que el SGC del programa cumple lo establecido en dicha norma. Su aplicación tiene como objetivo asegurar que los servicios ofrecidos satisfagan las necesidades de los laboratorios clínicos cumpliendo los requisitos legales requeridos y asegurando la mejora continua. El objetivo de este trabajo fue describir las acciones realizadas en la implementación del SGC y la posterior certificación de IRAM-ISO 9001:2015, por el IRAM.

Clinical laboratory determinations have a very important role in the evaluation, diagnosis, treatment and evolution of the health status of people. The reliability of their results is achieved through quality assurance and continuous improvement. The External Quality Assessment Programme Prof. Dr. Daniel Mazziotta has been accompanying clinical analysis laboratories for 31 years offering different tools to ensure analytical quality. It provides the services of external quality assessment, supply of material for internal quality control for determinations in Clinical Chemistry and solutions for instrumental control and sufficiency tests. Since the creation of the program, strategic objectives have been established to be developed in three stages: establishment, consolidation and support for quality management. A new stage is now being generated, whose final objective is accreditation. As a first step of this cycle, a quality management system (QMS) was implemented according to the requirements established in the IRAM Argentina standard-ISO 9001:2015. In August 2019, the Argentine Institute for Standardization and Certification (IRAM), representative in Argentina of the International Organization for Standardization (ISO), certified that the Programme's QMS complies with the provisions of said standard. Its application aims to ensure that the services offered meet the needs of clinical laboratories by fulfilling the legal requirements and ensuring continuous improvement. The objective of this work is to describe the actions carried out in the implementation of the QMS and the subsequent IRAM-ISO 9001: 2015 certification by the IRAM.

As determinações laboratoriais clínicas têm um papel muito importante na avaliação, diagnóstico, tratamento e evolução do estado de saúde das pessoas. A confiabilidade de seus resultados é alcançada através da garantia de qualidade e melhoria contínua. O Programa de Avaliação da Qualidade Externa "Prof. Dr. Daniel Mazziotta" apoia os laboratórios de análises clínicas há 31 anos, oferecendo diferentes ferramentas para garantir a qualidade analítica. Oferece os serviços de: avaliação externa de qualidade, fornecimento de material de controle interno de qualidade para determinações em Química Clínica e soluções para controle instrumental e testes de suficiência. Desde a criação do programa, os objetivos estratégicos foram estabelecidos para serem desenvolvidos em três etapas: estabelecimento, consolidação e suporte para a gestão da qualidade. Uma nova etapa é agora gerada, cujo objetivo final é a Acreditação. Como primeira etapa desse ciclo, um sistema de gestão da qualidade (SGQ) foi implementado de acordo com os requisitos estabelecidos na norma IRAM Argentina - ISO 9001:2015. Em agosto de 2019, o Instituto Argentino de Normalização e Certificação (IRAM), representante na Argentina da Organização Internacional de Normalização (ISO), certificou que o SGC do programa está em conformidade com as disposições da referida norma. Sua aplicação visa garantir que os serviços oferecidos satisfaçam as necessidades dos laboratórios clínicos, atendendo aos requisitos legais exigidos e garantindo a melhoria contínua. O objetivo deste trabalho é descrever as ações realizadas na implementação do SGQ e a subsequente certificação da IRAM-ISO 9001:2015, pela IRAM.

Aplicación de Seis Sigma en el Laboratorio Clínico / Six Sigma Application in the Clinical Laboratory

Seis Sigma es un método de mejora de procesos que se focaliza en disminuir la variabilidad de los mismos. El enfoque más común es contar los defectos, determinar el porcentaje, convertirlos a una tasa de defectos por millón y luego usar una tabla para buscar la métrica sigma apropiada. El segundo enfoque consiste en utilizar la medida de la variación del proceso para estimar la métrica sigma. En el laboratorio clínico se pueden aplicar ambos conceptos según la etapa del laboratorio en la cual se pretenda usar la métrica sigma. Para ambos enfoques un proceso de 6 sigmas es considerado un proceso eficiente, de alta calidad. En este trabajo se planteó para la etapa preanalítica una meta mínima de 4 sigmas. Algunos procesos muestran un buen desempeño con indicadores de calidad con sigmas mayores de 4. Sin embargo, varios de ellos tienen sigmas menores que la meta propuesta demostrando ser los más vulnerables. En Química Clínica y Hematología, la elección del requisito de calidad es el punto clave para armonizar la métrica sigma junto a la estrategia para la obtención del error sistemático y aleatorio. En este trabajo se muestran las diferentes estrategias para relacionar el desempeño basado en el sigma del proceso analítico con las reglas de validación de las corridas analíticas.

Six Sigma is a method for improvement of processes that focuses on reducing their variability. The most common approach is to count the defects, determine the percentage, convert them to a defect rate per million and then use a table to find the appropriate sigma metric. The second approach consists of using the process variation measure to estimate the sigma metric. In the clinical laboratory, both concepts can be applied according to the stage of the laboratory in which the sigma metric is intended to be used. For both approaches, a 6 sigma process is considered an efficient, high quality process. In this work, a minimum goal of 4 sigma was raised for the preanalytical stage. Some processes show good performance with quality indicators with sigma greater than 4. However, several of them have sigma lower than the proposed goal proving to be the most vulnerable. In Clinical Chemistry and Hematology, the choice of the quality requirement is the key point to harmonize the Sigma metric together with the strategy to obtain systematic and random error. This paper shows the different strategies to relate the performance based on the sigma of the analytical process with the validation rules of the analytical runs.

Seis Sigma é um método de melhoria de processos focado na redução da sua variabilidade. A abordagem mais comum é contar os defeitos, determinar a porcentagem, convertê-los numa taxa de defeitos por milhão e, depois disso, usar uma tabela para procurar a métrica sigma apropriada. A segunda abordagem consiste em usar a medida da variação do processo para estimar a métrica sigma. No laboratório clínico, podem ser aplicados os dois conceitos de acordo com a fase do laboratório em que se pretenda usar a métrica sigma. Para ambas as abordagens, um processo de 6-sigmas é considerado um processo eficiente e de alta qualidade. Neste trabalho, uma meta mínima de 4 sigmas foi definida para o estágio pré-analítico. Alguns processos mostram bom desempenho com indicadores de qualidade com sigmas maiores que 4. No entanto, vários deles têm sigmas menores que a meta proposta provando ser os mais vulneráveis. Em Química Clínica e Hematologia, a escolha do requisito de qualidade é o ponto chave para harmonizar a métrica sigma juntamente com a estratégia para obter o erro sistemático e aleatório. Este artigo mostra as diferentes estratégias para relacionar o desempenho baseado no sigma do processo analítico com as regras de validação das execuções analíticas.

Determination of vitamin D in tears of healthy individuals by the electrochemiluminescence method.

BACKGROUND: Vitamin D is a fat-soluble steroid hormone which can be converted into various forms and is of extreme physiological importance to our body. However, its functions and local metabolic pathways in some organs, such as the eye, have not yet been well studied. We aimed to verify the correlation between vitamin D levels in blood and tear fluid and the possibility of using tear fluid as a biological material for monitoring eye disorders in the future. METHODS: The electrochemiluminescence method was used to examine blood and tear samples collected with Schirmer test strips from 21 individuals without ocular disease. RESULTS: At the 95% confidence interval, mean tear fluid vitamin D = 37.8 ± 3.6 ng/mL, which is higher than the serum level, with a mean of 30.3 ± 7.7 ng/mL; Lin's concordance correlation coefficient = -0.018 (-0.174; 0.139), Pearson's coefficient = -0.070, and the Bland-Altman coefficient = -11.12 (-30.40; 8.16). Results were obtained using the program Stata version 11.0. CONCLUSION: It is possible to determine vitamin D levels in tear fluid using the electrochemiluminescence method, and as the results do not correlate with blood, there is possibility of using tear fluid as a biological matrix for detection of vitamin D, which may increase the possibilities of new studies in eye disorders.

Fasting conditions: Influence of water intake on clinical chemistry analytes.

INTRODUCTION: Currently available recommendations regarding fasting requirements before phlebotomy do not specify any maximum water intake volume permitted during the fasting period. The aim was to study the effects of 300 mL water intake 1 h before phlebotomy on specific analytes. MATERIALS AND METHODS: Blood was collected from 20 women (median age (min-max): 24 (22 - 50) years) in basal state (T0) and 1 h after 300 mL water intake (T1). Glucose, total proteins (TP), urea, creatinine, cystatin C, total bilirubin (BT), total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides (Tg), uric acid (UA), high-sensitivity C-reactive protein, gamma-glutamyl transferase (GGT), aspartate-aminotransferase (AST), alanine-aminotransferase and lactate-dehydrogenase (LD) were studied. Results were analyzed using Wilcoxon test. Mean difference (%) was calculated for each analyte and was further compared with reference change value (RCV). Only mean differences (%) higher than RCV were considered clinically significant. RESULTS: Significant differences (median T0vs median T1, P) were observed for TP (73 vs 74 g/L, 0.001); urea (4.08 vs 4.16 mmol/L, 0.010); BT (12 vs 13 µmol/L, 0.021); total cholesterol (4.9 vs 4.9 mmol/L, 0.042); Tg (1.05 vs 1.06 mmol/L, 0.002); UA (260 vs 270 µmol/L, 0.006); GGT (12 vs 12 U/L, 0.046); AST (22 vs 24 U/L, 0.001); and LD (364 vs 386 U/L, 0.001). Although the differences observed were statistically significant, they were not indicative of clinically significant changes. CONCLUSIONS: A water intake of 300 mL 1 h prior to phlebotomy does not interfere with the analytes studied in the present work.

Clinical, molecular and serological outcomes of the Chikungunya outbreak in Grenada

OBJECTIVE: This study evaluated the clinical utility of Chikungunya (CHIKV) test results and clinical symptoms in patients with suspected CHIKV infection. DESIGN AND METHODS: Patients with CHIKV symptoms who presented at a health facility in Grenada during the recent outbreak had a CHIKV diagnostic test form completed by a health professional and a blood sample was drawn. The serum sample was stored at -80oC, shipped to the Naval Infectious Diseases Diagnostic Lab (NIDDL) on dry ice and tested for CHIKV and Dengue (DENV) using PCR real-time assay for viral RNA, and IgM detection by ELISA. RESULTS: Sera from more than 600 patients collected from mid September till mid October, 2014 were drawn and had a CHIKV diagnostic form completed. At the time of writing 112 patients sera have been tested at the NIDDL. 90% of patients had a positive test. PCR only was positive in 8% of patients. IgM only was positive in 83%, and both PCR and IgM were positive in 9% of patients. The major symptoms presented by patients were joint pain (84%), fever (81%), body pain (74%), headache (62%), chills (54%) and rash (49%). CONCLUSION: IgM testing detected 92% of test positive patients while PCR alone detected 17%. The IgM assay was clinically most useful. In an outbreak where dengue is ruled out and CHIKV is the cause, patients with the constellation of symptoms above could be considered positive for CHIKV infection with a 98% accuracy without confirmatory testing.

Determination of insulin-like growth factor-I reference values using an immunoradiometric assay in a Brazilian adult population.

BACKGROUND: Serum levels of total insulin-like growth factor I (IGF-I) reflect endogenous growth hormone (GH) secretion in healthy adults, which makes it a good diagnostic marker for screening of GH-related disorders. Studies also have supported a possible relation between IGF-I levels and the risk and prognostic for some malignancies, besides a relation between IGF-I levels and mortality. OBJECTIVE: As the determination of the IGF-I normal values for local populations is strongly desired, the aim of this investigation was to determine reference values for IGF-I using an immunoradiometric assay (IRMA) in an adult Brazilian population of Rio de Janeiro city, since there is no other study using this methodology in Brazilian population, and that this method is widely used in Brazil and worldwide. MATERIALS AND METHODS: The study included samples of blood taken from 484 healthy subjects (251 men and 233 women) aged 18-70. The subjects agreed with this study, approved by the Ethical Committee of the Instituto Estadual de Hematologia Arthur de Siqueira Cavalcanti, Rio de Janeiro, Brazil. The samples were analyzed using a Diagnostic System Laboratories kit. For data analysis, age- and sex-specific figures were fitted after transformation of IGF-I values. RESULTS: In adulthood, a slow age-dependent decrease was found. There was no significant difference in IGF-I values between men and women. CONCLUSION: This study established age-specific IGF-I reference values, for a healthy Brazilian adult population, determined by a widely IGF-I, IRMA used currently in Brazil.

The coming of age of liquid chromatography coupled to tandem mass spectrometry in the endocrinology laboratory.

Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) has been rapidly incorporated in the routine of the endocrinology laboratory. Most endocrinologists are aware of the benefits afforded by this technique and tandem mass spectrometers are clearly no longer a mere research method but an important tool widely used for diagnosis. In the last 15 years, LC-MS/MS has replaced techniques such as immunoassay and HPLC for the analysis of hormones because it provides higher specificity and good sensitivity. Also, it permits simultaneous measurement of several analytes and sample preparation and acquisition are fast and simple. Although several strategies based on LC-MS/MS have been described in the last 15 years, there is still room for improvement. The impact of matrix effects and isobaric interferences have been addressed by only a few studies, and standardization with reference materials is available for a limited number of analytes. This review summarizes the application of LC-MS/MS in analyzing three classes of hormones: steroids, derivatives of the aromatic amino acids, and peptides and proteins. The benefits and current limitations of LC-MS/MS will be discussed for these hormone categories.

Analytical interference of quinolone antibiotics and quinine derived drugs on urinary protein determined by reagent strips and the pyrogallol red-molybdate protein assay.

OBJECTIVES: To investigate the analytical interference of drugs in urinary protein and to estimate the lowest interfering concentrations. DESIGN AND METHODS: Drug supplemented urine samples were compared to the control with two reagent strips and the total protein was determined using Pyrogallol Red-Molybdate (PRM). RESULTS: False-positive interferences occurred with Multistix 10 SG for hydroxychloroquine, levofloxacin and ofloxacin. No interference was observed with Combur 10 Test M. Statistically significant false-positive interferences were observed in the PRM assay with all tested drugs, and lowest interfering concentrations were mostly above estimated therapeutic concentrations. The PRM assay "confirmed" the results of the Multistix dipstick, so a real proteinuria could be presumed from the double analytical interference. CONCLUSIONS: This is the first report of analytical interference by quinolone and quinine derivatives in the PRM assay. Special attention to patients using these drugs is needed to minimize errors in the interpretation of urinary protein results.

Errores más usuales en la sección Química Clínica del Laboratorio Clínico / Most common errors of the Clinical Chemistry section of the Clinical Pathology Laboratory

Fundamento: Minimizar los errores en el laboratorio clínico es premisa fundamental del trabajo diario por la alta incidencia sobre la morbilidad y mortalidad. Objetivo: Contribuir a la actualización sobre los errores en la sección Química Clínica, así como reflexionar sobre posibles pautas para el trabajo. Desarrollo: Se presentan los errores que competen a las fases de trabajo en el laboratorio clínico: preanalítica, analítica y posanalítica, independientemente del nivel de atención y el equipamiento con el cual cuentan en la sección Química Clínica. Conclusiones: La prevención de los errores sobre la base de mecanismos de control debe constituir parte importante del trabajo diario en el laboratorio lo cual redundará en un mejor manejo de la salud del paciente(AU)

Background: To minimize errors in the clinical pathology laboratory is a fundamental requisite of daily work due to its high influence on morbidity and mortality. Objective: Contributing to update on the errors in the Clinical Chemistry Section, and reflect on possible guidelines for this job. Development: A presentation is made of errors corresponding to stages of work in the clinical pathology laboratory: preanalytical, analytical and posanalytical, regardless of the level of care and equipment available for the Clinical Chemistry section. Conclusions: The prevention of errors on the basis of control mechanisms should be an important part of daily work in the pathology laboratory which will result in a better management of the patient's health. Keywords: Errors, clinical chemistry, clinical chemistry, clinical laboratory, preanalytical, analytical, posanalítica(AU)

A simple and inexpensive automated technique for measurement of serum nitrite/nitrate.

OBJECTIVE: We described an automated technique for measurement of serum nitrite/nitrate (NO(x)) using the Cobas Mira clinical chemistry analyzer. DESIGN AND METHODS: NO(x) was measured by the modified Griess method. Precision, accuracy, linearity, instrument carry-over and lower limit of quantitation (LLOQ) were assessed. RESULTS: The automated technique for measurement of serum NO(x) was linear, precise, and accurate. It has a LLOQ of 2.0 µmol/L. CONCLUSION: Serum NO(x) measured by the modified Griess method can be applied easily to the Cobas Mira clinical chemistry analyzer.

Impacto del Programa de Evaluación Externa de la Calidad en Química Clínica en México de 2004 a 2008 / Impact of the Program of External Quality Assessment in Clinical Chemistry in Mexico from 2004 to 2008 / Impacto do Programa de Avaliação Qualidade Externa em Química Clínica no México de 2004 a 2008

Se valoró el impacto del Programa de Evaluación Externa de la Calidad, aplicable a laboratorios clínicos en el área de Química Clínica, en México, con base en resultados obtenidos por los laboratorios durante el ciclo marzo 2008-febrero 2009 y el periodo 2004-2008, mediante un estudio analítico, longitudinal y retrospectivo de los resultados obtenidos por los laboratorios que participaron en el Programa de Evaluación Externa de la Calidad de la Facultad de Ciencias Químicas, Universidad Autónoma de San Luis Potosí. El análisis estadístico se realizó con los programas Microsoft® Office Excel y Epi Info T. El porcentaje de laboratorios clínicos con desempeño aceptable (excelente y bueno) por analito, durante el ciclo de evaluación marzo 2008-febrero 2009, fue del 75% al 82%, que aumentó cuando se utilizaron métodos automatizados y semiautomatizados. Para el periodo 2004-2008, los laboratorios en 2004 tuvieron 3,02 veces mayor riesgo de no calificar con desempeño aceptable (p<0,05) que en 2008. En conclusión, el Programa de Evaluación Externa de la Calidad de la Facultad de Ciencias Químicas, Universidad Autónoma de San Luis Potosí, ha tenido un impacto favorable en el desempeño global de los laboratorios clínicos, que permite asegurar su calidad analítica.

The impact of the External Quality Assessment Program, applicable to clinical laboratories in the area of Clinical Chemistry in Mexico, was studied, based on laboratory results during the March 2008-February 2009 cycle and the 2004-2008 period, through analytical, longitudinal, retrospective analyses of the results obtained by the laboratories that participated in the External Quality Assessment Program of the School of Chemical Sciences of Universidad Autónoma de San Luis Potosí. Statistical analysis was performed with Microsoft® Office Excel and Epi Info T programs. The percentage of clínical laboratories with acceptable performance (excellent and good) by analyte during the evaluation cycle in March 2008-February 2009 was 75% to 82%, whích íncreased when automated and semíautomated methods were used. For the 2004-2008 period, the laboratories, in 2004, had 3.02 times greatet risk of not qualifying with acceptable performance (p<0.05) than in 2008. In conclusión, the External Qualíty Assessment of the School of Chemícal Sciences of Universidad Autónoma de San Luis Potosí has had a strong impact on the overall performance of clinical laboratories, whích ensures the latter's qualíty.

17alpha-hydroxyprogesterone and cortisol serum levels in neonates and young children: influence of age, gestational age, gender and methodological procedures.

To determine the influence of age, gestational age, gender and methodological protocol on serum 17OHP and cortisol concentrations. 17OHP in non-extracted (NE) and extracted (E) sera was measured by RIA in 319 full-term (FT) (1 d-5 yr) infants, 38 pre-term (PT) and in 19 neonates with classical CAH at diagnosis. 17OHP (NE- and E-) decreased with age in normal children. The extraction procedure significantly reduced 17OHP by eliminating interfering steroids in children < 1 year. Sexual dimorphism was only observed in NE-17OHP. 17OHP in PT was always higher than in FT up to 2 months of age (p < 0.001). Neither NE- nor E-17OHP in CAH overlapped with those of FT or PT (p < 0.001) allowing to omit the extraction procedure to confirm CAH diagnosis. Cortisol levels were within normal range in neonates with CAH, thus not adding useful information about adrenal function. Chronological and gestational age, gender, and extraction for 17OHP measurement are important factors to know when assessing adrenal function during the first year of life.