Reference Intervals of Hematology and Clinical Chemistry Analytes for 1-Year-Old Korean Children

BACKGROUND: Reference intervals need to be established according to age. We established reference intervals of hematology and chemistry from community-based healthy 1-yr-old children and analyzed their iron status according to the feeding methods during the first six months after birth. METHODS: A total of 887 children who received a medical check-up between 2010 and 2014 at Boramae Hospital (Seoul, Korea) were enrolled. A total of 534 children (247 boys and 287 girls) were enrolled as reference individuals after the exclusion of data obtained from children with suspected iron deficiency. Hematology and clinical chemistry analytes were measured, and the reference value of each analyte was estimated by using parametric (mean±2 SD) or nonparametric methods (2.5-97.5th percentile). Iron, total iron-binding capacity, and ferritin were measured, and transferrin saturation was calculated. RESULTS: As there were no differences in the mean values between boys and girls, we established the reference intervals for 1-yr-old children regardless of sex. The analysis of serum iron status according to feeding methods during the first six months revealed higher iron, ferritin, and transferrin saturation levels in children exclusively or mainly fed formula than in children exclusively or mainly fed breast milk. CONCLUSIONS: We established reference intervals of hematology and clinical chemistry analytes from community-based healthy children at one year of age. These reference intervals will be useful for interpreting results of medical check-ups at one year of age.

¿Cuándo dos exámenes seriados de laboratorio representan un cambio en el estado de salud de un paciente? / When two consecutive laboratory results indicate a change in health status in a patient?

Sources of variation between two serial tests must be considered in interpreting if there was a clinically significant change. The main causes of variation are the biological variation coefficient (CVB) of the test in question, which must be obtained from the literature, and the analytical coefficient of variation (CVA) of the same test, which must be obtained from the internal quality control laboratory data. With both data we can calculate the critical difference or “reference change value” which helps us to decide whether there was a real change in the patient’s health.

A simple, cost-effective quality assurance model for measurement of lipids in a large epidemiological study.

Background. Laboratory measurements are an integral part of epidemiological studies in cardiovascular disease. Standardization and quality assurance is of utmost importance in the context of multicentre studies. Methods. We evaluated a simple and cost-effective method of quality assurance for measurement of total cholesterol, high density lipoprotein (HDL) cholesterol and triglycerides in a study involving 10 centres. Three methods for quality assessment were used for the study that involved measurement of cholesterol, triglycerides and HDL cholesterol and included internal quality control, external quality control and 10% repeat analysis in addition to a uniform standardized protocol developed for the 10 centres. External quality control material was prepared and circulated by the coordinating laboratory. Results. External quality control material was distributed 20 times during the study. The mean variance index suggested a substantial improvement in the performance of participating laboratories over a period of time for cholesterol and triglycerides. This was also evident in the improvement in per cent technical error as a measure of bias and a higher correlation between replicates of samples analysed in the coordinating laboratory and the participating centres for cholesterol, triglycerides and HDL cholesterol. Conclusion. A cost-effective quality assurance model for laboratory measurement using local capacities was developed and implemented in a multicentre epidemiology study. Such a programme would be useful for developing countries where cost-cutting is important.

Fortalecimiento de la calidad: uso apropiado de la tecnología del laboratorio de análisis clínicos / Strengthning of the quality: appropriate use of the technology of the laboratory of clinical analysis

En el momento actual, en el que prevalece un fuerte gradiente en la evolución de la tecnología, los bioquímicos clínicos nos vemos a veces superados por la velocidad con la que debemos actualizar nuestros conocimientos y habilidades en el uso de las técnicas más apropiadas para la creciente demanda. Al mismo tiempo, debemos recomendar al equipo médico nuestros criterios sobre el uso más conveniente de las mismas, dado que la cantidad de determinaciones diferentes es cada vez mayor y en muchos casos, su interpretación, más compleja. Tanto el funcionamiento como las aplicaciones de estas tecnologías no siempre son suficientemente conocidas por el equipo de salud, por lo cual su utilización no genera los beneficios esperados e inversamente, en ocasiones, se hace uso incorrecto de la metodología disponible, indicando en primera instancia análisis clínicos como en otros servicios de soporte diagnóstico, no debe ser sobrevalorada y se debe usar en su justa medida, de la menor hacia la mayor complejidad, de acuerdo al oportuno criterio profesional, no limitando el uso sino la utilización innecesaria, evitando el derroche y con máxima eficiencia. Para el cumplimiento de esta propuesta, es necesario hacer un uso criterioso de la tecnología disponible, tanto cualitativa como cuantitativamente, por lo cual estas acciones resultarán en mejores servicios para nuestros pacientes, acortamiento de los tiempos de atención y una disminución de los costos operativos, cuyos recursos podrán ser utilizados para mejorar otros procesos.

[Evaluation of HDL-C determination methods]

Following confirmation of the role of HDL-C role in cardiovascular disease, its measurement has become a fixed requirement by physicians. Today serum HDL-C is measured using different methods from simple outdated precipitation methods to the latest of homogenous assays used for HDL-C determination. However, the precision, accuracy and performance, standardization, and evaluation for those methods are controversial. This paper briefly discusses the methodology of various HDL-C determination methods e.g ultra centrifugation, electrophoresis, precipitation and homogenous assays, and advantages of homogenous methods. Human expertise, time consuming and high cost instrumentation of ultra centrifugation, quantitative electrophoresis, nuclear magnetic resonance and chromatographic methods are key factors that make the methods undesirable for clinical laboratories. Precipitation and manual separation steps of non homogenous HDL-C determination methods, reduces their precision, and causes them to be replaced by more precise methods such as homogenous assays; however more time is needed for their costs to be more competitive

Normalización en el sector químico clínico: I) El contexto internacional / Standardization in clinical chemistry: I) The international environment

Durante los últimos 40 años, el esfuerzo de normalización del laboratorio clínico se ha basado en la convicción de ésta profesión de proporcionar servicios analíticos confiables y oportunos. En términos prácticos, la normalización del laboratorio clínico tiene distintas orientaciones y resultados. Dentro del proceso de normalización se incluye el desarrollo de materiales y métodos de referencia, la expedición de leyes, reglamentos y normas técnicas, así como el establecimiento de recomendaciones y lineamientos profesionales. El nivel y las actividades de normalización de la química clínica, no obstante, no se conocen de modo suficiente y claro. El objetivo de ésta serie de artículos es hacer una síntesis de los aspectos más relevantes del asunto en el mundo (primer parte) y en México (segunda parte), en modo de contar con un documento de referencia que pueda facilitar la actualización de los químicos clínicos en ésta materia y la modernización de los laboratorios clínicos de éste país acorde con el concierto internacional

Report of NEQAP--the ten years growth success.

External quality assessment forms a vital aspect of health laboratory service. Decisionto start National External quality assessment Programme (NEQAP) under IAPM was taken at the Annual conference at Bombay in December, 1989 to be run from Varanasi at the initiative of the author. It has been running now for more than ten years and is unique in that it does not have financial backing from government or any institution and runs by contributions from participants and help from IAPM from time to time. Another unique feature is that it is truly multiparametric including clinical chemistry, hematology, microbiology and cytology. It covers about 300 labs from all corners of India. Details of the IAPM-NEQAP programme made during successful running for ten years (1990-1999) and recommendations for further action are given.

Reference methods in clinical chemistry.

For the measurements of analyses such as glucose, creatinine etc, in clinical chemistry, definitive methods and standard reference materials are available. On the other hand, for the measurements of the catalytic activity concentration of enzymes, various methods have been developed and those methods have generated a variety of results and reference ranges, difficulties in the interpretation of results, and difficulties in external quality assessment programs. Therefore, for the measurement of the catalytic activity of an enzyme, reference method is very important as the first start to obtain an accurate and precise result. We report the present situation of standardization for the measurement of the catalytic activity of enzymes and the comparison of reference methods including standards or consensus methods for the representative enzymes recommended by International Federation of Clinical Chemistry and the representative societies of clinical chemistry, and the survey results produced by Japan Medical Association.

Quality assessment in clinical chemistry: a Thailand experience.

A Thailand quality assessment program called "The External Quality Assessment in Clinical Chemistry, EQAC" was found in 1986. Ablind lyophilized control serum is monthly-cycle distributed to the participants and the returned test-report values are evaluated by a computed program. Evaluated report Variance Index Scores (VIS) and grades of test and mean score of all tests are posted back to the participants including a back of "The Newsletter of the EQAC". The development has been indicated by an increasing number of active participants and an improvement due to decreasing Variance Index Scores. In 1998 the program was applied by 324 laboratory participants of which 59% of general hospital and community health hospital laboratory, 29% of private hospital laboratory including polyclinics, and 12% of the others. By now as many as 144 trials of 23 biochemistry tests at different methods were assessed from the EQAC program. Participant communication, knowledge update and enhanced quality encouragement have been managed by mean of participants' VIS from 120 to 93 during 1987-1998.

External quality assurance in Malaysia.

An activity supportive of the MOH QA Programme, the National EQAS for clinical chemistry monitors for analytical performance in core routine biochemical testing by the pathology laboratories, with unsatisfactory performance scores serving to alert against deficiencies or problems and the scores in subsequent challenges providing the feedback of effectiveness of remedial actions taken. While unacceptable individual analyte performance score (variance index score, VIS) indicated problems in instruments, reagent and calibrators, or the use of inherently poorer methods, repeated occurrence of unsatisfactory OMRVIS was traceable to generally poor laboratory management of usually inadequately-equipment small laboratories. The outcome has been one of slow but gradual improvement in the overall performance of participating laboratories, with a move towards methods upgrading and standardization to achieve greater concordance of results. Presently, the programme is limited to 61 government and 4 private hospital laboratories in the country for 12 commonly assayed clinical biochemistry analytes. It is hoped that the NEQAS could be extended to the other private laboratories and that of academic institutions. However, this is dependent to a large extent on the manpower and financial support obtainable by the organizing body of the programme in the future. Belk and Sunderman, 1947 demonstrated that laboratories participating in an quality assessment scheme could rapidly and dramatically improve their analytical performance. In some countries, participation has become mandatory, and acceptable performance is a requirement in laboratory accreditation. The need and value of the NEQAP is, therefore, evident. While there may be limitations in the national programme. efforts are being made at improving the programme within the means and resources of the organising body. The goals of the NEQAP are not just to monitor performance but also to educate. On this, matters related to and supportive of these goals have also been pursued. The annual workshop/forum on quality controls had allowed exchange of information between representatives of participating laboratories and the organising body. Recently in the 1997 MOH Quality Improvement evaluation, Quality Control has been evaluated together with the other 17 such activities. The study on knowledge, attitude and practice has provided the necessary feedback and will be used for future planning in making efforts at increasing the effectiveness and benefits of the all QC activities including this NEQAP for clinical chemistry. In addition, there is a need to look into areas such as selection of methods and test systems, and improvement of continuing education, training as well as research in quality improvement as suggested by the Quality Improvement evaluation.

Interpretaçäo rápida e precisa de resultados de exames / Rapid and precise interpretation of tests results

A contribuição dada por um teste para a formulação do diagnóstico nem sempre está clara para o médico. A estimativa da probabilidade do diagnóstico após a realização de testes através da aplicação da razão de verossimilhança é um método simples, rapido e preciso. Apresentam as seis etapas do método e um exemplo simples para melhor compreensão. Uma vez que a sensibilidade e a especificidade são propriedades estáveis dos exames, a melhor maneira de se aprimorar a estimativa da probabilidade pós-teste é uma criteriosa avaliação clínica antes dos exames serem solicitados. Foram elaborados cinco exercícios para permitir que os leitores possam aplicar o método