[Moyamoya in Aragon: epidemiology and self-perception of quality of life]. / Moyamoya en Aragón. Epidemiología y calidad de vida autopercibida.

INTRODUCTION: Moyamoya angiopathy is a vasculopathy caused by stenosis/occlusion of one or both intracranial internal carotid arteries. Although more common in Eastern countries, its prevalence is increasing in the West. An angioresonance or angiography is essential for its diagnosis. There are two options for treatment: conservative (medical) treatment or surgical bypass techniques. PATIENTS AND METHODS: Nineteen patients were selected using International Classification of Diseases codes, and their demographic characteristics and health outcomes were studied. They were administered a scale for the screening of anxious-depressive syndrome (the Hospital Anxiety and Depression Scale - HADS) and another scale for self-perceived quality of life (SF-36). After applying the inclusion/exclusion criteria, eight of these patients were studied. RESULTS: Nineteen patients were studied (52.63% male, 57.89% European) and the Aragonese prevalence was estimated at 1.37/100,000 inhabitants. The most frequent clinical presentation was ischaemic stroke (73.68%). The HADS detected two positive cases of anxiety and one case of depression. According to the SF-36, the worst self-rated aspects were vitality (median: 35/100) and general health (median: 42.5/100), while the best rated was physical function (mean: 93.57/100). CONCLUSIONS: This is the Spanish series with the highest prevalence and the only one that addresses self-perceived health and screening of the anxious-depressive syndrome. Further research is needed to address this entity and determine its true prevalence in the West.

TITLE: Moyamoya en Aragón. Epidemiología y calidad de vida autopercibida.Introducción. La angiopatía de moyamoya es una vasculopatía originada por la estenosis/oclusión de una o ambas carótidas internas intracraneales. Aunque es más frecuente en países orientales, está aumentando su prevalencia en Occidente. Para su diagnóstico es imprescindible una angiorresonancia o una angiografía. En su tratamiento hay dos opciones: el tratamiento conservador (médico) o las técnicas quirúrgicas de bypass. Pacientes y métodos. Se seleccionó a 19 pacientes mediante códigos de la Clasificación internacional de enfermedades, y se estudiaron sus características demográficas y resultados en salud. Se les administró una escala para el cribado de síndrome ansiosodepresivo ­escala de ansiedad y depresión hospitalaria (HADS)­ y otra de autopercepción de calidad de vida (SF-36). De estos pacientes, se estudió a ocho al aplicar los criterios de inclusión/exclusión. Resultados. Se estudió a 19 pacientes (52,63%, hombres; 57,89%, europeos) y se estimó la prevalencia aragonesa en 1,37/100.000 habitantes. La clínica más frecuente fue el ictus isquémico (73,68%). La HADS detectó dos casos positivos para ansiedad y un caso de depresión. Según el SF-36, los aspectos peor autopercibidos fueron la vitalidad (mediana: 35/100) y la salud general (mediana: 42,5/100); mientras que el mejor valorado fue la función física (media: 93,57/100). Conclusiones. Se trata de la serie española con mayor prevalencia y la única que aborda la salud autopercibida y el cribado del síndrome ansiosodepresivo. Son necesarios más estudios que permitan abordar esta entidad y cuál es la verdadera prevalencia en Occidente.

Moyamoya en Aragón. Epidemiología y calidad de vida autopercibida / Moyamoya in Aragon: epidemiology and self-perception of quality of life

Introducción La angiopatía de moyamoya es una vasculopatía originada por la estenosis/oclusión de una o ambas carótidas internas intracraneales. Aunque es más frecuente en países orientales, está aumentando su prevalencia en Occidente. Para su diagnóstico es imprescindible una angiorresonancia o una angiografía. En su tratamiento hay dos opciones: el tratamiento conservador (médico) o las técnicas quirúrgicas de bypass. Pacientes y métodos Se seleccionó a 19 pacientes mediante códigos de la Clasificación internacional de enfermedades, y se estudiaron sus características demográficas y resultados en salud. Se les administró una escala para el cribado de síndrome ansiosodepresivo –escala de ansiedad y depresión hospitalaria (HADS)– y otra de autopercepción de calidad de vida (SF-36). De estos pacientes, se estudió a ocho al aplicar los criterios de inclusión/exclusión. Resultados Se estudió a 19 pacientes (52,63%, hombres; 57,89%, europeos) y se estimó la prevalencia aragonesa en 1,37/100.000 habitantes. La clínica más frecuente fue el ictus isquémico (73,68%). La HADS detectó dos casos positivos para ansiedad y un caso de depresión. Según el SF-36, los aspectos peor autopercibidos fueron la vitalidad (mediana: 35/100) y la salud general (mediana: 42,5/100); mientras que el mejor valorado fue la función física (media: 93,57/100). Conclusiones Se trata de la serie española con mayor prevalencia y la única que aborda la salud autopercibida y el cribado del síndrome ansiosodepresivo. Son necesarios más estudios que permitan abordar esta entidad y cuál es la verdadera prevalencia en Occidente. (AU)

INTRODUCTION Moyamoya angiopathy is a vasculopathy caused by stenosis/occlusion of one or both intracranial internal carotid arteries. Although more common in Eastern countries, its prevalence is increasing in the West. An angioresonance or angiography is essential for its diagnosis. There are two options for treatment: conservative (medical) treatment or surgical bypass techniques. PATIENTS AND METHODS Nineteen patients were selected using International Classification of Diseases codes, and their demographic characteristics and health outcomes were studied. They were administered a scale for the screening of anxious-depressive syndrome (the Hospital Anxiety and Depression Scale – HADS) and another scale for self-perceived quality of life (SF-36). After applying the inclusion/exclusion criteria, eight of these patients were studied. RESULTS Nineteen patients were studied (52.63% male, 57.89% European) and the Aragonese prevalence was estimated at 1.37/100,000 inhabitants. The most frequent clinical presentation was ischaemic stroke (73.68%). The HADS detected two positive cases of anxiety and one case of depression. According to the SF-36, the worst self-rated aspects were vitality (median: 35/100) and general health (median: 42.5/100), while the best rated was physical function (mean: 93.57/100). CONCLUSIONS This is the Spanish series with the highest prevalence and the only one that addresses self-perceived health and screening of the anxious-depressive syndrome. Further research is needed to address this entity and determine its true prevalence in the West. (AU)

Prevention of Alzheimer's disease: a global challenge for next generation neuroscientists.

The incidence of dementia is rapidly increasing in developed countries due to social and demographic changes. This trend is expected to worsen in the coming decades, with the number of cases possibly even tripling in the next 25 years. Therefore Alzheimer's disease (AD) prevention is becoming a global health priority. Our knowledge of the pathophysiological process leading to the development of pathological brain lesions that characterize AD has increased exponentially in recent years. However, the phenotypic expression of AD not only depends on the development of senile plaques and neurofibrillary tangles but other factors also play a role. Thus, over the last few decades, epidemiological studies have revealed several risk factors for developing AD, such as vascular or lifestyle related factors. Having the current knowledge on AD, two different strategies have been developed for the prevention of AD: one is based on primary prevention by acting on modifiable risk factors, the other is a pathophysiology-driven approach aimed to identify individuals in a preclinical stage of the disease and treating them with drugs purporting to act on molecular targets of the amyloid cascade. Several promising trials with these approaches are currently ongoing and results are expected in the next few years. The intrinsic limitations in the design of preventive trials should be overcome through a global effort involving healthy population, healthcare professionals, governments, industry, and scientific institutions. This exertion will be more than compensated if we can make AD a preventable disease.

[Encephalitis associated to anti-NMDA receptor antibodies: a description of two cases in the child/youth population]. / Encefalitis asociada a anticuerpos antirreceptor de NMDA: descripcion de dos casos en poblacion infantojuvenil.

INTRODUCTION: The clinical diagnosis of encephalitis due to anti-glutamate receptor N-methyl D-aspartate (NMDA) antibodies (anti-NMDA encephalitis) is made more complex by the fact that psychiatric clinical features are usually predominant in the early stages. This can lead to a delay in the diagnosis, treatment and prognosis of the disease. CASE REPORTS: We report on two clinical cases attended by the Child/Youth Psychiatry Section of our hospital, in collaboration with the Paediatric and Neurology services. Case 1: a 4-year-old male who was referred owing to behavioural alterations and the regression of previously acquired skills. Case 2: a 13-year-old female who was admitted due to a behavioural disorder within the context of a possible initial psychotic episode. In both cases appropriate complementary tests were performed, including lumbar puncture and anti-NMDA antibodies, which were positive. Once the diagnosis of anti-NMDA encephalitis had been reached, treatment was started: in the first case, with intravenous perfusion of corticoids and immunoglobulins, while in the second rituximab had to be associated. Both patients progressed towards clinical improvement. CONCLUSIONS: Over the last two years there has been an increase in the number of cases of anti-NMDA encephalitis diagnosed in the child/youth population. It is a neuropsychiatric, autoimmune condition, which can correspond to a paraneoplastic syndrome. Follow-up and transvaginal ultrasonography as well as thoracoabdominal computerised axial tomography scans are recommended for at least two years after diagnosis. Early diagnosis and treatment are important, which means that a multi- and interdisciplinary approach is required.

Encefalitis asociada a anticuerpos antirreceptor de NMDA: descripción de dos casos en población infantojuvenil / Encephalitis associated to anti-NMDA receptor antibodies: a description of two cases in the child/youth population

Introducción. El diagnóstico clínico de encefalitis por anticuerpos antirreceptor de N-metil-D-aspartato (NMDA) del glutamato(encefalitis anti-NMDA) es complejo debido a que al inicio suele predominar la clínica psiquiátrica. Esto puede conllevar un retraso en el diagnóstico, tratamiento y pronóstico de la enfermedad.Casos clínicos. Presentamos dos casos clínicos atendidos por la Sección de Psiquiatría Infanto-Juvenil de nuestro hospital,en colaboración con los servicios de Pediatría y Neurología. Caso 1: varón de 4 años remitido por alteración de conducta y regresión de habilidades previamente adquiridas. Caso 2: mujer de 13 años ingresada por alteración de la conducta en un contexto de posible primer episodio psicótico. En ambos casos se hacen las pruebas complementarias oportunas,incluyendo punción lumbar y anticuerpos anti-NMDA, que son positivos. Una vez realizado el diagnóstico de encefalitisanti-NMDA, se inicia el tratamiento: en el primer caso, con perfusión intravenosa de corticoides e inmunoglobulinas y, en el segundo, es necesario asociar rituximab. La evolución de ambos fue hacia la mejoría clínica. Conclusiones. Se observa un aumento del diagnóstico de encefalitis anti-NMDA en población infantojuvenil en los dos últimos años. Se trata de un cuadro neuropsiquiátrico y autoinmune, que puede corresponder a un síndrome paraneoplásico.Se recomienda seguimiento y la realización de una ecografía transvaginal y tomografía computarizada toracoabdominaldurante al menos dos años tras el diagnóstico. Es importante realizar un diagnóstico y tratamiento precoces, por lo que resulta necesario un abordaje multi e interdisciplinar (AU)

Introduction. The clinical diagnosis of encephalitis due to anti-glutamate receptor N-methyl D-aspartate (NMDA) antibodies(anti-NMDA encephalitis) is made more complex by the fact that psychiatric clinical features are usually predominant in the early stages. This can lead to a delay in the diagnosis, treatment and prognosis of the disease.Case reports. We report on two clinical cases attended by the Child/Youth Psychiatry Section of our hospital, in collaborationwith the Paediatric and Neurology services. Case 1: a 4-year-old male who was referred owing to behavioural alterations andthe regression of previously acquired skills. Case 2: a 13-year-old female who was admitted due to a behavioural disorder within the context of a possible initial psychotic episode. In both cases appropriate complementary tests were performed, including lumbar puncture and anti-NMDA antibodies, which were positive. Once the diagnosis of anti-NMDA encephalitishad been reached, treatment was started: in the first case, with intravenous perfusion of corticoids and immunoglobulins, while in the second rituximab had to be associated. Both patients progressed towards clinical improvement. Conclusions. Over the last two years there has been an increase in the number of cases of anti-NMDA encephalitis diagnosedin the child/youth population. It is a neuropsychiatric, autoimmune condition, which can correspond to a paraneoplastic syndrome. Follow-up and transvaginal ultrasonography as well as thoracoabdominal computerised axial tomography scans are recommended for at least two years after diagnosis. Early diagnosis and treatment are important, which means that a multi- and interdisciplinary approach is required (AU)

Application of the Technology Web 2.0 in a drug information centre.

OBJECTIVE: To develop a Web 2.0 resource map and select those that may be useful in a Drug Information Centre at a Hospital Pharmacy Department (CIMSF). METHOD: A multidisciplinary working group under the Biomedical Information Commission selected some of the Web 2.0 resources included in the Guía d'usos i estil a les xarxes Socials guide of the Catalonian Government. RESULTS: Six resources were selected: Netvibes, Delicious, Google groups, Google Docs, Slideshare and Twitter. These tools were used for 5 months to manage biomedical information for the medical staff, and to provide external visibility by providing information to other health professionals. More than a thousand hits were recorded on the portal Netvibes and more than 100 professionals followed CIMSF on Twitter. CONCLUSIONS: The Web 2.0 offers useful, user-friendly and cost-efficient tools which could be implemented in a CIMSF, while also enabling participation in external networks of pharmacotherapeutic interest, increasing its visibility to other professionals.

Terapias eléctricas en vuelo / In-flight electrical therapy

Presentamos dos casos de terapias eléctricas instauradas en vuelo. El primer caso es un varón de 55 años con síndrome coronario agudo con elevación del ST. Tras la atención inicial sufre un episodio de fibrilación ventricular en vuelo que precisa de cuatro descargas entre 200 y 360 J. En el segundo caso se describe el uso en vuelo de un marcapasos transitorio en un varón de 78 años con diagnóstico electrocardiográfico de fibrilación auricular lenta que resultó ser secundario a un tratamiento con coliriobeta-bloqueante. En ambas atenciones participó un helicóptero A109-E® (año de fabricación:2003, horas de vuelo/año: 250), fabricado por Agusta, equipado con un monitor-desfibrilador (monofásico) Responder 3000®, fabricado por Marquette-Hellige. No se detectaron interferencias con el equipo electrónico del helicóptero ni durante el uso de dichas terapias ni en los minutos posteriores. Ambos pacientes recibieron tratamientos definitivos en su hospital terciario correspondiente, y pudieron ser dados de alta hospitalaria en los días siguientes (AU)

We report 2 cases in which electrical therapy was applied in flight. After a 55-year-old man with acute coronary syndrome with ST elevation was initially stabilized, he experienced ventricular fibrillation in flight and was given 4 shocks between 200 and 360 J. A 78-year-old man with an electrocardiographic diagnosis of slow atrial fibrillation, related to use of â-blocker eye drops, was treated with a temporary pacemaker in flight. Both cases were managed in an AgustaA109-E helicopter built in 2003 (250 flying hours per year) and equipped with a monophasic monitor-defibrillator(Responder 3000, Marquette-Hellige). No interference from the helicopter's electrical equipment was detected during therapy or afterwards. Both patients completed treatment in the corresponding tertiary care hospital and were discharged in the following days (AU)

Sodium balance during U. S. football training in the heat: cramp-prone vs. reference players.

U. S. football players with a history of heat cramps were evaluated for the effect of physical training, sodium intake, and loss of sweat sodium on whole blood sodium concentration (BNa). Athletes (n=14 males, 24+/-1 y) were recruited and studied based on medical history, age, and position. The reference group (R, n=8 without a cramping history) and cramp-prone group (C, n=6, history of whole-body cramps associated with extensive sweat loss during exercise in the heat) were measured for body mass and BNa (ISTAT) before and after team training of 2.2 h in hot conditions (WBGT=29-32 degrees C). Intake and loss of fluid and sodium were also measured to determine respective acute balance. In R, BNa was stable pre- to post-training (138.9+/-1.8 to 139.0+/-2.0 mmol/L) while it tended to decline in C (137.8+/-2.3 to 135.7+/-4.9 mmol/L), and three subjects in C had BNa values below 135 mmol/L (131.7+/-2.9 mmol/L). C consumed a greater percentage of total fluid as water (p<0.05). Mean sweat sodium concentration was (52.6+/-29.2 mmol/L for C and 38.3+/-18.3 mmol/L for R (p>0.05). Compared to R, C tended to experience a decline in BNa and greater acute sodium imbalance. These changes may place cramp-prone players at greater risks for developing acute sodium deficits during training.

[Mortality in patients with multiple injuries: analysis using the trauma and injury severity score in a referral hospital]. / Análisis de la mortalidad en los pacientes politraumatizados según la metodología TRISS en un hospital traumatológico de referencia.

BACKGROUND AND OBJECTIVES: A growing number of patients with multiple injuries are being treated. Injury severity scales can be used to assess outcomes objectively. This study aimed to assess our hospital's cases on the basis of the Trauma and Injury Severity Score (TRISS) and compare outcomes to those reported in the Major Trauma Outcome Study, as well as to determine preventable mortality and analyze causes of death and associated factors. PATIENTS AND METHODS: Data were extracted from the records of patients admitted with multiple injuries in 2005 and were used to calculate the Revised Trauma Score (RTS), the Injury Severity Score (ISS), and the TRISS or probability of survival. Hospital mortality was also calculated. A TRISS between 25 and 50 was considered to indicate a preventable avoidable death; a TRISS over 50 indicated a preventable death. Logistic regression analysis was used to identify factors associated with mortality. RESULTS: We studied the cases of 198 patients with a mean (SD) age of 43.9 (19) years. Ninety-three percent had suffered blunt trauma. The mean ISS, the prehospital RTS, and the TRISS were 16.9 (11.2), 10.8 (2.5), and 0.95 (0.2), respectively. Twenty-five patients died. Fifteen deaths were classified as preventable or potentially preventable. Factors related to exitus were head injury and age (odds ratios, 4.6 and 4.0, respectively). CONCLUSIONS: The rate of preventable death in our hospital was higher than expected. Mortality was strongly associated with head injury and age. The TRISS model can identify preventable deaths objectively.

Análisis de la mortalidad en los pacientes politraumatizados según la metodología TRISS en un hospital traumatológico de referencia / Mortality in patients with multiple injuries: analysis using the Trauma and Injury Severity Score in a referral hospital

OBJETIVOS: Los pacientes politraumatizados representanun grupo creciente. Las escalas de gravedad permitenuna valoración objetiva de los resultados. El objetivode este estudio ha sido comparar la evaluación de lospacientes atendidos en nuestro centro mediante la metodologíadel Trauma and Injury Severity Score (TRISS),con la Major Trauma Outcome Study (MTOS) y determinarla mortalidad evitable, analizando las causas demuerte y los factores asociados con la mortalidad.PACIENTES Y MÉTODOS: Mediante una base de datos delos pacientes politraumatizados ingresados en el año 2005se calculó de manera retrospectiva el Revised Trauma Score(RTS), el Injury Severity Score (ISS), el TRISS o probabilidadde supervivencia (Ps) y la mortalidad hospitalaria.Un valor de TRISS entre 25-50 se consideró “mortalidadpotencialmente evitable” y un valor mayor de 50 “mortalidadevitable”. Se aplicó el análisis de regresión logísticapara ver qué factores se asociaban a la mortalidad.RESULTADOS: Se estudiaron 198 pacientes con una edadpromedio de 43,9 ± 19. El 93% fueron traumatismos cerrados.El ISS, el RTS prehospitalario y el TRISS medio fueronde 16,9 ± 11,2; 10,8 ± 2,5 y 0,95 ± 0,2 respectivamente.Hubo 25 muertes de las cuales 15 se clasificaron como mortalidadevitable o potencialmente evitable. Los factoresrelacionados con el exitus fueron el traumatismo craneoencefálico(Odds ratio 4,6) y la edad (Odds ratio 4,0).CONCLUSIONES: Hallamos una mortalidad evitablemayor de la esperada y una fuerte asociación del traumatismocraneoencefálico y la edad con la mortalidad.El modelo TRISS puede definir de manera objetiva lamortalidad evitable(AU)

BACKGROUND AND OBJECTIVES: A growing number ofpatients with multiple injuries are being treated. Injuryseverity scales can be used to assess outcomesobjectively. This study aimed to assess our hospital’scases on the basis of the Trauma and Injury SeverityScore (TRISS) and compare outcomes to those reportedin the Major Trauma Outcome Study, as well as todetermine preventable mortality and analyze causes ofdeath and associated factors.PATIENTS AND METHODS: Data were extracted from therecords of patients admitted with multiple injuries in2005 and were used to calculate the Revised TraumaScore (RTS), the Injury Severity Score (ISS), and theTRISS or probability of survival. Hospital mortality wasalso calculated. A TRISS between 25 and 50 wasconsidered to indicate a preventable avoidable death; aTRISS over 50 indicated a preventable death. Logisticregression analysis was used to identify factorsassociated with mortality.RESULTS: We studied the cases of 198 patients with amean (SD) age of 43.9 (19) years. Ninety-three percenthad suffered blunt trauma. The mean ISS, theprehospital RTS, and the TRISS were 16.9 (11.2), 10.8(2.5), and 0.95 (0.2), respectively. Twenty-five patientsdied. Fifteen deaths were classified as preventable orpotentially preventable. Factors related to exitus werehead injury and age (odds ratios, 4.6 and 4.0,respectively).CONCLUSIONS: The rate of preventable death in ourhospital was higher than expected. Mortality wasstrongly associated with head injury and age. TheTRISS model can identify preventable deathsobjectively(AU)

Análisis y evaluación del helitransporte sanitario en Aragón / Analysis and evaluation of the helicopter emergency medical service in Aragon

Introducción: El uso del helicóptero para la atención sanitaria urgente en Aragón data del año 2000. Desde entonces 1.055 pacientes han sido atendidos por el equipo medicalizado del 112-SOS Aragón. Métodos: Se realiza un estudio descriptivo retrospectivo simple de los 999 últimos pacientes atendidos por el helicóptero sanitario desde el 10 de mayo de 2001 hasta el 12 de septiembre de 2005. Resultados: De los 999 pacientes analizados el 81,1% fueron atendidos en el lugar del suceso (servicio primario) y el 18,9% fue un traslado interhospitalario (servicio secundario). Las patologías más frecuentes estuvieron relacionadas con el accidente traumático (40,9% accidentes de tráfico y 12,7% accidente laboral) y con la emergencia cardiovascular en 12% de los pacientes. Estas dos patologías ocuparon casi el 70% de los pacientes atendidos. De los menores de 45 años, el 47% sufren accidentes de tráfico y de los mayores de 45, un 26% padecen eventos cardiovasculares (p < 0,001). Existen otras patologías atendidas como son accidentes deportivos (7,6%), domésticos (2,3%), emergencias neonatales (2,4%), respiratorias (2%), autólisis, agresiones o incendios, aunque con menor prevalencia. Conclusiones: El helicóptero 112 SOS Aragón representa un importante recurso dentro del sistema de emergencias sanitarias de la Comunidad Autónoma de Aragón. El estudio ha permitido determinar el perfil del paciente grave que recibe atención sanitaria urgente desde este servicio. El paciente crítico (traumatizado grave, neonato y cardiaco) es el que principalmente se beneficia del helitransporte sanitario, sobre todo, cuando se encuentran en áreas rurales distantes de un hospital de referencia (AU)

I ntroduction: The use of the helicopter for the sanitary urgent attention in Aragon dates from year 2000. Since then 1055 patients has been attended by the medical equipment of 112-SOS Aragon. Methods: there is realized a descriptive retrospective simple study of the last 999 patients attended by the sanitary helicopter from the 10 of May of 2001 to the 12 of September of 2005. Result: Of all 999 analyzed patients, 81,1% were taken care of in the place of the event (primary service) and 18,9% were a interhospital movement (secondary service). The most frequent pathologies related to the traumatic accident (40,9% traffic accidents and 12,7% labour accident) and the cardiovascular emergency with 12% of the patients. These two pathologies almost occupied 70% of treated patients. Of the minors of 45 years, 47% suffers traffic accidents and of the greater ones of 45 years, 26% suffers cardiovascular processes (p < 0.001). Other taken care of pathologies exists as they are sports accidents (7,6%), domestic accidents (2,3%), neonative emergencies (2,4%), respiratory (2%), autolisis, aggressions, fires… with smaller prevalence. Conclusions: The helicopter 112 SOS Aragon represents an important resource within the system of sanitary emergencies of the Autonomous Community of Aragon. The study has allowed determine the profile of the serious patient who received urgent sanitary attention from this service. The critical patient (traumatized serious, neonates and cardiac) is the one that mainly benefits from transports by helicopter, mainly, when they are in distant rural areas of a hospital of reference (AU)

Pre-metrological (pre-analytical) variation of some biochemical quantities.

It is customary to assume that pre-metrological variation is negligible if all pre-metrological sources of variation have been standardised. The aim of this study was to quantify the pre-metrological variation of some biochemical quantities frequently measured in clinical laboratories. The experimental design considers the different sources of pre-metrological variation that usually act day-to-day on samples from patients. The results demonstrate that, for many quantities, the pre-metrological variance is not negligible; consequently, it is suggested that these variances should be taken into account when estimating the uncertainty of measurement of patients' results.

Evaluation of the VALAB expert system.

The validation of a clinical laboratory report is a process that guarantees the results contained in the report have been obtained under satisfactory metrological conditions and that they are compatible with the information available on the patient. This validation is generally carried out manually by a clinical laboratory professional, but also may be done by an expert system properly programmed, such as the VALAB system. The evaluation presented in this article consists of comparing human and system decisions of validation for 500 randomly selected clinical laboratory reports from hospitalized patients. In this evaluation, 84.8% of the reports examined by the VALAB are accepted directly without any human aid, and only 15.2% require examination by clinical biochemists.

Multicentric reference values: shared reference limits.

In order to obtain shared reference limits, three laboratories in the same geographical area with a homogeneous population have developed a proposal to produce multicentric reference values. The strategy simulates a virtual laboratory, actually formed by the laboratories involved; the reference limits produced in the virtual laboratory are in fact derived from the blend of reference values obtained by each laboratory. Each laboratory has chosen its own reference sample and has measured the biochemical quantities under study. Reference individuals (n = 171) and 15 biochemical quantities among the most measured in clinical laboratories were selected. The reference values obtained in each laboratory were blended when permitted by the Harris & Boyd test (Clin Chem 1990; 36:265-70). The multicentric reference limits obtained by the virtual laboratory for each quantity were estimated according to the recommendations of the International Federation of Clinical Chemistry. For each quantity, each laboratory, with the results observed in their reference sample, estimated the diagnostic specificity, using as cut-off values the corresponding multicentric reference limits. Each observed value of diagnostic specificity was compared with the theoretical diagnostic specificity value, equal to 0.975, that should be observed when a reference limit is used as cut-off value. The multicentric reference limits obtained by the virtual laboratory are valid in all cases with the exception of the upper reference limit for the concentrations of calcium(II) and urate in serum in one of the laboratories.