Macroprolactin: From laboratory to clinical practice.

Prolactin measurement is very common in standard clinical practice. It is indicated not only in the study of pituitary adenomas, but also when there are problems with fertility, decreased libido, or menstrual disorders, among other problems. Inadequate interpretation of prolactin levels without contextualizing the laboratory results with the clinical, pharmacological, and gynecological/urological history of patients leads to erroneous diagnoses and, thus, to poorly based studies and treatments. Macroprolactinemia, defined as hyperprolactinemia due to excess macroprolactin (an isoform of a greater molecular weight than prolactin but with less biological activity), is one of the main causes of such erroneous diagnoses, resulting in poor patient management when not recognized. There is no unanimous agreement as to when macroprolactin screening is required in patients with hyperprolactinemia. At some institutions, macroprolactin testing by polyethylene glycol (PEG) precipitation is routinely performed in all patients with hyperprolactinemia, while others use a clinically based approach. There is also no consensus on how to express the results of prolactin/macroprolactin levels after PEG, which in some cases may lead to an erroneous interpretation of the results. The objectives of this study were: 1. To establish the strategy for macroprolactin screening by serum precipitation with PEG in patients with hyperprolactinemia: universal screening versus a strategy guided by the alert generated by the clinician based on the absence or presence of clinical symptoms or by the laboratory when hyperprolactinemia is detected. 2. To create a consensus document that standardizes the reporting of prolactin results after precipitation with PEG to minimize errors in the interpretation of the results, in line with international standards.

Macroprolactin: From laboratory to clinical practice. / Macroprolactina: del laboratorio a la práctica clínica. Recomendaciones del grupo de trabajo de laboratorio de la SEEN y de la comisión de hormonas de la SEQCML sobre la medición e informe del resultado de la macroprolactina.

Prolactin measurement is very common in standard clinical practice. It is indicated not only in the study of pituitary adenomas, but also when there are problems with fertility, decreased libido, or menstrual disorders, among other problems. Inadequate interpretation of prolactin levels without contextualizing the laboratory results with the clinical, pharmacological, and gynecological/urological history of patients leads to erroneous diagnoses and, thus, to poorly based studies and treatments. Macroprolactinemia, defined as hyperprolactinemia due to excess macroprolactin (an isoform of a greater molecular weight than prolactin but with less biological activity), is one of the main causes of such erroneous diagnoses, resulting in poor patient management when not recognized. There is no unanimous agreement as to when macroprolactin screening is required in patients with hyperprolactinemia. At some institutions, macroprolactin testing by polyethylene glycol (PEG) precipitation is routinely performed in all patients with hyperprolactinemia, while others use a clinically based approach. There is also no consensus on how to express the results of prolactin/macroprolactin levels after PEG, which in some cases may lead to an erroneous interpretation of the results. The objectives of this study were: 1. To establish the strategy for macroprolactin screening by serum precipitation with PEG in patients with hyperprolactinemia: universal screening versus a strategy guided by the alert generated by the clinician based on the absence or presence of clinical symptoms or by the laboratory when hyperprolactinemia is detected. 2. To create a consensus document that standardizes the reporting of prolactin results after precipitation with PEG to minimize errors in the interpretation of the results, in line with international standards.

Estrategia para el diagnóstico de las dislipidemias. Recomendación 2018 / Strategy for the diagnosis of dyslipidaemias

Las dislipidemias son alteraciones del metabolismo lipídico que cursan con concentraciones de lípidos alteradas, tanto por exceso como por defecto. Estas alteraciones están fuertemente asociadas con el proceso aterosclerótico, y se ha demostrado que el control de dichas alteraciones consigue disminuir la incidencia de episodios de origen isquémico. Diagnosticar las dislipidemias desde un punto de vista etiológico es muy importante, ya que el riesgo cardiovascular al que predispone cada una de ellas es diferente, dependiendo del tipo de lipoproteína que esté alterada y de su concentración. Por ello es de gran utilidad disponer de algoritmos diagnósticos sencillos que incluyan magnitudes del metabolismo lipídico disponibles en la mayoría de los laboratorios clínicos, con el fin de realizar el diagnóstico inicial del tipo de dislipidemia, en caso de poseer las herramientas diagnósticas adecuadas identificarla y, en caso contrario, disponer de la información apropiada para recomendar la ampliación del estudio en otro centro que disponga de los recursos necesarios para establecer el diagnóstico

Dyslipidaemias are alterations in lipid metabolism that involve an excess, as well as a deficit, in lipid concentrations. These alterations are strongly associated with atherosclerosis, and it has been shown that its control reduces the incidence of episodes of ischaemic origin. Diagnosing dyslipidaemias from an aetiological point of view is very important, since the cardiovascular risk to which each one predisposes is different, and depends on the type of lipoprotein that is altered and its concentration. For this reason, it is very useful to have simple diagnostic algorithms that include the measurements of lipid metabolism that are available in most clinical laboratories in order to make the initial diagnosis of the type of dyslipidaemia. In the case of having the right diagnostic tools, identify it; and if not, to have the appropriate information to recommend the extension of the study in another centre with resources to establish the diagnosis

Recomendaciones para la estandarización de la medida de lípidos y lipoproteínas. Recomendación (2018) / Recommendations for the standardisation of lipids and lipoproteins measurements. Recommendation (2018)

Este documento describe recomendaciones para la estandarización de la medida de las magnitudes lipídicas, puesto que resultan críticas para la toma de decisiones clínicas. Deben emplearse métodos recomendados validados frente a un método de referencia o definitivo, y materiales de control que cumplan con la Directiva Europea sobre Diagnóstico in vitro; deben cumplir también los objetivos recomendados por el National Cholesterol Education Program (NCEP) y la Sociedad Española de Medicina del Laboratorio (SEQCML). La determinación de colesterol de HDL por métodos homogéneos en equipos automatizados se considera aceptable para la práctica rutinaria, y la fórmula de Friedewald utilizable para estimar la concentración de colesterol de LDL siempre que las concentraciones de triglicéridos sean iguales o inferiores a 200mg/dL (2,3mmol/L); en otro caso, se recomienda utilizar la concentración de colesterol-no-HDL. La cuantificación rutinaria de apolipoproteínas A1 y B, y lipoproteína (a), puede efectuarse por métodos de inmunonefelometría e inmunoturbidimetría, con calibradores trazables a materiales de referencia

Some recommendations are presented for standardising the measurement of lipids and lipoproteins, as they are critical for clinical decisions making. Recommended methods validated against a reference or definitive method should be employed, as well as the use of control materials that comply with European Directives on in vitro diagnostics. Additionally, the chosen methods must comply with the objectives set forth by the National Cholesterol Education Program (NCEP) and by the Spanish Society of Laboratory Medicine (SEQCML). Determination of HDL cholesterol using automatic homogenous methods is considered acceptable for normal clinical practice, and the Friedewald Formula is considered to be usable to estimate LDL cholesterol concentration when triglyceride concentrations are below 200mg/dL (2.3mmol/L). If this should not be the case, the use of non-HDL cholesterol is recommended. Routine quantification of apolipoproteins A1 and B, and lipoprotein (a) can be measured using immunonephelometric or immunoturbidimetric methods, with calibrators that are traceable to reference materials

Removing Lipemia in Serum/Plasma Samples: A Multicenter Study.

BACKGROUND: Lipemia, a significant source of analytical errors in clinical laboratory settings, should be removed prior to measuring biochemical parameters. We investigated whether lipemia in serum/plasma samples can be removed using a method that is easier and more practicable than ultracentrifugation, the current reference method. METHODS: Seven hospital laboratories in Spain participated in this study. We first compared the effectiveness of ultracentrifugation (108,200×g) and high-speed centrifugation (10,000×g for 15 minutes) in removing lipemia. Second, we compared high-speed centrifugation with two liquid-liquid extraction methods-LipoClear (StatSpin, Norwood, USA), and 1,1,2-trichlorotrifluoroethane (Merck, Darmstadt, Germany). We assessed 14 biochemical parameters: serum/plasma concentrations of sodium ion, potassium ion, chloride ion, glucose, total protein, albumin, creatinine, urea, alkaline phosphatase, gamma-glutamyl transferase, alanine aminotransferase, aspartate-aminotransferase, calcium, and bilirubin. We analyzed whether the differences between lipemia removal methods exceeded the limit for clinically significant interference (LCSI). RESULTS: When ultracentrifugation and high-speed centrifugation were compared, no parameter had a difference that exceeded the LCSI. When high-speed centrifugation was compared with the two liquid-liquid extraction methods, we found differences exceeding the LCSI in protein, calcium, and aspartate aminotransferase in the comparison with 1,1,2-trichlorotrifluoroethane, and in protein, albumin, and calcium in the comparison with LipoClear. Differences in other parameters did not exceed the LCSI. CONCLUSIONS: High-speed centrifugation (10,000×g for 15 minutes) can be used instead of ultracentrifugation to remove lipemia in serum/plasma samples. LipoClear and 1,1,2-trichlorotrifluoroethane are unsuitable as they interfere with the measurement of certain parameters.

El informe analítico ideal del perfil lipídico. Necesidad de un consenso / The ideal lipid report: a need for consensus

No disponible

Homogeneización de los valores del perfil lipídico / Homogenization of the lipid profile values

Los informes analíticos del laboratorio clínico son claves para orientar a los médicos clínicos sobre qué valores del perfil lipídico se han de considerar alterados y, por tanto, requieren intervención. Desafortunadamente, existe una gran heterogeneidad en los valores de lípidos que los laboratorios clínicos reportan como «normales, deseables, recomendables o de referencia». Ello puede dificultar la toma de decisiones clínicas y ser una barrera para la consecución de los objetivos terapéuticos en prevención cardiovascular. Una reciente recomendación internacional añade un nuevo factor de heterogeneidad en la interpretación del perfil lipídico, como es la posibilidad de medirlo sin ayuno previo. Todo ello justifica la necesidad de desarrollar un documento que adapte el conocimiento existente a la práctica clínica de nuestro sistema sanitario. En este sentido, profesionales de diferentes sociedades científicas implicadas en la medida y utilización de los datos del perfil lipídico han desarrollado el presente documento para establecer unas recomendaciones que faciliten la homogenización del mismo (AU)

Analytical reports from the clinical laboratory are essential to guide clinicians about what lipid profile values should be considered altered and, therefore, require intervention. Unfortunately, there is a great heterogeneity in the lipid values reported as "normal, desirable, recommended or referenced" by clinical laboratories. This can difficult clinical decisions and be a barrier to achieve the therapeutic goals for cardiovascular prevention. A recent international recommendation has added a new heterogeneity factor for the interpretation of lipid profile, such as the possibility of measuring it without previous fasting. All this justifies the need to develop a document that adapts the existing knowledge to the clinical practice of our health system. In this regard, professionals from different scientific societies involved in the measurement and use of lipid profile data have developed this document to establish recommendations that facilitate their homogenization (AU)

Homogenization of the lipid profile values. / Homogeneización de los valores del perfil lipídico.

Analytical reports from the clinical laboratory are essential to guide clinicians about what lipid profile values should be considered altered and, therefore, require intervention. Unfortunately, there is a great heterogeneity in the lipid values reported as "normal, desirable, recommended or referenced" by clinical laboratories. This can difficult clinical decisions and be a barrier to achieve the therapeutic goals for cardiovascular prevention. A recent international recommendation has added a new heterogeneity factor for the interpretation of lipid profile, such as the possibility of measuring it without previous fasting. All this justifies the need to develop a document that adapts the existing knowledge to the clinical practice of our health system. In this regard, professionals from different scientific societies involved in the measurement and use of lipid profile data have developed this document to establish recommendations that facilitate their homogenization.

Proteomic analysis of intraluminal thrombus highlights complement activation in human abdominal aortic aneurysms.

OBJECTIVE: To identify proteins related to intraluminal thrombus biological activities that could help to find novel pathological mechanisms and therapeutic targets for human abdominal aortic aneurysm (AAA). APPROACH AND RESULTS: Tissue-conditioned media from patients with AAA were analyzed by a mass spectrometry-based strategy using liquid chromatography coupled to tandem mass spectrometry. Global pathway analysis by Ingenuity software highlighted the presence of several circulating proteins, among them were proteins from the complement system. Complement C3 concentration and activation were assessed in plasma from AAA patients (small AAA, AAA diameter=3-5 cm and large AAA, AAA diameter >5 cm), showing decreased C3 levels and activation in large AAA patients. No association of a combination of single-nucleotide polymorphisms in complement genes between large and small AAA patients was observed. Intense extracellular C3 inmunostaining, along with C9, was observed in AAA thrombus. Analysis of C3 in AAA tissue homogenates and tissue-conditioned media showed increased levels of C3 in AAA thrombus, as well as proteolytic fragments (C3a/C3c/C3dg), suggesting its local deposition and activation. Finally, the functional role of local complement activation in polymorphonuclear (PMN) cell activation was tested, showing that C3 blockade by anti-C3 antibody was able to decrease thrombus-induced neutrophil chemotaxis and reactive oxygen species production. CONCLUSIONS: A decrease of systemic C3 concentration and activity in the later stages of AAA associated with local complement retention, consumption, and proteolysis in the thrombus could induce PMN chemotaxis and activation, playing a detrimental role in AAA progression.

¿Podemos utilizar la apolipoproteína B en la toma de decisiones para la intervención en el riesgo cardiovascular de pacientes con triglicéridos elevados? / Can apolipoprotein B be used for making decisions on cardiovascular risk prevention in patients with raised triglycerides?

Objetivo. Analizar el valor predictivo de diversas aproximaciones: cuantificación de la concentración de apolipoproteína B (apoB), estimación del cLDLf y estimación del no-cHDL, como predictivos de elevaciones de la magnitud de la concentración de cLDL. Material y métodos. Estudio multicéntrico transversal en el que se han analizado las muestras rutinarias de 6.094 pacientes consecutivos. En cada paciente se ha cuantificado el cLDL mediante una técnica de ultracentrifugación de rutina (cLDLu) y la concentración de apoB por uno de los métodos inmunológicos estandarizados y se ha estimado el cLDLf y el no-cHDL. Las magnitudes obtenidas han sido utilizadas para analizar sus valores predictivos del cLDLu en función de tres grupos de concentración de Tg (<200, entre 200 y 400 y más de 400mg/dL) y los grupos de riesgo definidos por el ATPIII (cLDL>70, 100, 130 o 160mg/dL). Resultados y conclusiones. Con todas las magnitudes analizadas se obtiene un buen valor predictivo positivo, variable para las diferentes concentraciones de Tg y que es máximo para la apoB con puntos de corte de alta especificidad (AE). Las estimaciones con cLDLf infraestiman la situación de riesgo del paciente, mientras que las que utilizan el no-cHDL la sobreestiman. Conclusión. En pacientes con Tg<200mg/dL puede utilizarse prácticamente sin riesgo la fórmula de Friedewald; en pacientes con Tg elevados es recomendable la apoB (puntos de corte de AE) como predictor positivo y el no-cHDL como predictor negativo (AU)

Objective. To analyse the predictive value of several approaches to cardiovascular risk prevention: measuring apolipoprotein B concentrations (apoB), estimation of fractionated LDL cholesterol (cLDLf) and non-HDL cholesterol (HDLc), to predict increases in LDL cholesterol. Material and Methods. Cross-sectional multicentre study in which routine samples from 6094 consecutive patients were analysed. In each patient, LDLc was quantified by routine ultracentrifugation technique (LDLu) and apoB concentrations by a standard immunological method. We also estimated the LDLf and non-HDLc. The values obtained were used to analyse the predictive values of unfractionated LDL cholesterol (cLDLu) into three groups according to their triglyceride concentration (<200, between 200 and 400 and 400mg/dL) and risk groups as defined by the Adult Treatment Panel (ATP) III guidelines (LDL-C> 70, 100, 130 or 160mg/dL). Results and conclusions. With all the variables analysed we obtained a good positive predictive value, which varied according to the triglyceride concentrations, with the highest values being obtained for apoB with high specificity cut-off points (AE). Calculations with LDLf values underestimate the patient's risk, while those using non-HDLc overestimate it. Conclusion. The Friedewald formula can be used practically without risk in patients with triglycerides below 200mg/dL. In patients with elevated triglycerides, apoB (AE cut-off points) is recommended as a positive predictor, and non-HDLc as a negative predictor (AU)

Evaluación de la medición de bilirrubina total en el analizador GEM(R) Premier(TM) 4000 / Evaluation of Total Bilirubin measurements on the GEM(R) Premier(TM) 4000 blood gas analyser

Introducción. La medición exacta y precisa de bilirrubina es fundamental en el diagnóstico y tratamiento de la ictericia neonatal. Objetivos. Evaluar la medición de bilirrubina total en el módulo de cooximetría del analizador Gem(R) Premier(TM) 4000 (Instrumentation Laboratory) con el propósito de utilizarlo de forma rutinaria en nuestro hospital. Material y método. Se han estudiado muestras de suero (n=113) y de sangre (n=90) procedentes de recién nacidos y 111 muestras de suero y 64 de sangre de adultos con bilirrubina total entre 2-20 y 1,5-42mg/dL respectivamente y se han comparado los resultados con el método de 2,5-diclorofenildiazonio en el analizador Cobas(R) 711 (Roche Diagnostics). La comparación de procedimientos se realizó con el análisis de regresión lineal según Passing-Bablok y la concordancia de resultados se analizó con las gráficas de Bland-Altman. Resultados. La imprecisión obtenida (CV) es menor a 4%. En el estudio de muestras de adultos no encontramos diferencias significativas. En las muestras de recién nacidos las pendientes de las rectas de regresión son 1,076 (1,035-1,097) en muestras de suero y 1,093 (1,028-1,148) en muestras de sangre. Las diferencias absolutas entre los métodos son de 0,6 (-1,3 a 2,6) mg/dL en suero y 0,3 (-1,3 a 1,9) mg/dL en sangre. Conclusiones. Las diferencias encontradas entre los procedimientos evaluados no son significativas en muestras de adultos. En muestras de sangre de RN se observa un error proporcional del 9,3% con diferencias de > 2 mg/dL respecto al método habitual en el 3,3% de ellas. El analizador GEM(R) Premier(TM) 4000 puede ser una alternativa adecuada para la medición de bilirrubina total en muestras de sangre de recién nacidos en las unidades de neonatología y en los laboratorios clínicos (AU)

Introduction. The exact and precise measurement of bilirubin is fundamental in the diagnosis and treatment of neonatal jaundice. Objective. To evaluate the measurement of total bilirubin on the co-oximetry module of the Gem(R) Premier(TM) 4000 analyser (Instrumentation Laboratory), in order to use it in our hospital. A total of 113 samples of serum and 90 of blood from new-borns (NB), and 111 serum and 64 blood samples from adults, with a range of total bilirubin between 2-20 and 1.5-42 mgldL respectively, were measured. The results were compared with the 2,5-dichlorophenyldiazonium method on the Cobas(R) 711 analyser (Roche Diagnostics). Comparisons of procedures were calculated with linear regression analysis according to the Passing-Bablok equation and the assessment agreement of methods was analyzed with the Bland-Altman plots. Results. The total imprecision (CV) was less than 4%. No significant differences were found in the study of the adult samplesIn samples of newborns the slopes of the regression lines were 1.076 (1.035 to 1.097) in the newborn serum samples and 1.093 (1.028 to 1.148) in blood samples. The absolute difference between the methods was 0.6 (-1.3 to 2.6) mg/dL in serum and 0.3 (-1.3 to 1.9) mg/dL in blood. Conclusions. There were no significant differences between the procedures evaluated in adult samples. In NB whole blood samples the proportional error was 9,3%, with discrepancies > 2 mg/dL compared to the routine method in 3,3% of them. The GEM(R) Premier(TM) 4000 analyzer could be a suitable alternative for the quantification of bilirubin in blood samples from new-borns in the neonatal units and clinical laboratories (AU)

Evaluación multicéntrica de distintos métodos para la determinación de colesterol HDL directo con respecto al colesterol HDL de precipitación / Multicentre evaluation of different methods for the determination of direct HDL-cholesterol compared to the precipitation method

Introducción. Los resultados de los programas de garantía de calidad indican que existen diferencias significativas entre los métodos homogéneos disponibles para la medición del colesterol HDL. Sin embargo, la posible influencia de efectos matriz en las muestras liofilizadas empleadas y la ausencia de un valor verdadero en estas muestras, hace difícil la valoración completa de estos métodos. En este estudio experimental multicéntrico hemos comparado los métodos homogéneos más utilizados en nuestro medio, con respecto al de precipitación de ácido fosfotúngstico-MgCl2. Material y métodos. Cada laboratorio procesó unas 100 muestras de suero de pacientes por uno o dos métodos homogéneos y envió alícuotas congeladas de las muestras analizadas al laboratorio central donde se procesaron por el método de precipitación. Resultados. Las imprecisiones de los métodos homogéneos fueron buenas e inferiores a las de precipitación, que cumplía las especificaciones de calidad para sesgo y error total (ET). Sin embargo, no todos los métodos homogéneos cumplían los objetivos de calidad mínimos, pues algunos procedimientos producían sesgos positivos muy altos (en relación al método de comparación) y uno un sesgo negativo muy bajo. El estudio de la concordancia, realizado estratificando a los pacientes según las concentraciones de colesterol HDL, mostró diferencias entre los métodos. Conclusiones. Estos resultados sugieren que existen discrepancias en la valoración de las magnitudes obtenidas con los métodos homogéneos, probablemente generada por una elevada inexactitud en algunos de ellos y que es conveniente que los laboratorios conozcan las caracteristicas de imprecisión y sesgo del metodo directo que utilizan con respecto al de referencia (AU)

Introduction. The results of quality assurance programs suggest that there are significant differences between the homogeneous methods available for the measurement of HDL cholesterol. However, the possible influence of matrix effects in the lyophilized samples used and the absence of a true value in these samples means that a full assessment of these methods cannot be made. In this multicentre pilot study we compared the most used homogeneous methods in our country with the phosphotungstic acid-MgCl2 method. Material and methods. Each laboratory processed about one hundred serum samples from patients with one or two homogeneous methods and sent frozen aliquots of the samples in special packaging with dry ice to the central laboratory where they were processed by the precipitation method. Results. The imprecision of homogeneous methods were good and lower than those of the precipitation method, and met the quality specifications for bias and total error (TE). However, not all homogeneous methods met the minimum quality objectives, as some procedures produced a very high positive bias (relative to the comparison method) and one, a low negative bias. In addition, the study of the agreement between methods, made by stratifying patients according to HDL cholesterol concentrations, showed differences. Conclusions. These results suggest that there are discrepancies in the assessment of the levels obtained with homogeneous methods, probably due to a high inaccuracy in some of them, and it is advised that the laboratories be aware of the characteristics of inaccuracy and bias of the direct method used compared to the reference method (AU)

Valor pronóstico de marcadores inflamatorios y perfil lipídico en pacientes con claudicación intermitente. Estudio piloto / Prognostic value of inflammatory markers and lipid profile in patients suffering from intermittent claudication – a pilot study

Fundamento y objetivo: Analizar variables clínicas y serológicas (perfil lipídico, marcadores inflamatorios) como potenciales factores de riesgo para el desarrollo de eventos cardiovasculares y mortalidad a corto plazo en pacientes con claudicación intermitente. Pacientes y método: Incluimos todos los pacientes con diagnóstico inicial de claudicación intermitente vascular en nuestro centro durante 2005-2006. Analizamos datos clínicos, parámetros serológicos (creatinina, colesterol total, colesterol unido a lipoproteínas de baja densidad [colesterol LDL], colesterol unido a lipoproteínas de alta densidad [colesterol HDL], apolipoproteína A1, apolipoproteína B100, lipoproteína(a), homocisteína, proteína C reactiva, velocidad de sedimentación globular [VSG], fibrinógeno), eventos cardiovasculares y mortalidad durante el seguimiento a 1-3 años. Resultados:Incluimos 162 pacientes, de los que 143 (88,3%) eran varones. La edad media (DE) fue de 66 (10,4) años (extremos 41-86), 76 (46,9%) eran fumadores activos, 96 (59,3%) hipertensos, 56 (34,6%) diabéticos y 129 (79,6%) hipercolesterolémicos. Registramos 16 (9,9%) eventos coronarios/cerebrovasculares, 18 (11,1%) eventos vasculares en extremidades inferiores y 9 (5,9%) muertes tardías durante el seguimiento (media de 18,2 [8] meses). La hipertensión arterial fue el único predictor de eventos coronarios o cerebrovasculares (p=0,013); la cardiopatía y el colesterol HDL<45mg/dL se asociaron de forma independiente a eventos vasculares de extremidades inferiores (p=0,021 y 0,049), y la VSG>20mm/h a mortalidad (p=0,008). Conclusiones: Las cifras reducidas de colesterol HDL y elevadas de VSG han resultado factores de riesgo independientes para eventos vasculares periféricos y mortalidad a corto plazo (AU)

Background and objective: To analyse clinical and serological variables (lipid profile, inflammatory biomarkers) as potential risk factors for the development of short-term cardiovascular events and mortality in patients suffering from intermittent claudication. Patients and methods: We included all patients with a first-time diagnosis of vascular intermittent claudication in our center during 2005-2006. We analysed clinical data, serological parameters (creatinine, total cholesterol, LDL-cholesterol, HDL-cholesterol, ApolipoproteinA1, ApolipoproteinB100, lipoprotein(a), homocysteine, C-reactive protein, erythrocyte sedimentation rate [ESR], fibrinogen), cardiovascular events and mortality during 1-3 year follow-up.Results: We included 162 patients: 143 (88.3%) men, mean (SD) age 66 (10.4) (41-86) years, 76 (46.9%) active smokers, 96 (59.3%) hypertensive, 56 (34.6%) diabetic, 129 (79.6%) hypercholesterolemic. We registered 16 (9.9%) coronary/cerebrovascular events, 18 (11.1%) lower limb vascular events and 9 (5.9%) late deaths during follow-up (mean [SD] 18.2 [8] months). Hypertension was the only predictor of coronary or cerebrovascular events (p=0.013); heart disease and HDL-cholesterol<45mg/dL were independent risk factors for lower limb vascular events (p=0.021 and 0.049), and ESR>20mm/h was associated with all-cause death (p=0.008). Conclusions: Reduced HDL-cholesterol and elevated ESR have emerged as independent risk factors for short-term lower limb vascular events and death

Multicentric evaluation of the homogeneous LDL-cholesterol Plus assay: comparison with beta-quantification and Friedewald formula.

OBJECTIVES: To evaluate the analytical and clinical performance of a new version of the LDL-C Plus assay and compare it with the beta-quantification (BQ) method in a multicenter study. DESIGN AND METHODS: Direct LDL-C was measured in 169 fresh pooled samples and in 830 clinical samples with known LDL-C by BQ. The reactivity of lipoproteins and the effect of hemoglobin, bilirubin and chylomicrons (CM) were studied. RESULTS: Direct LDL-C total imprecision was <2.2%; inaccuracy <+/-2.5% (unaffected by triglycerides up to 9.5 mmol/L); and total error 9.8%. Direct assay reacted with 95%, 50% and 25% of the cholesterol in the LDL, intermediate (IDL) and VLDL fractions, respectively. A significant association was observed with BQ. Icteric samples showed a negative bias and the effect of CM was variable. A positive bias was observed when VLDL-cholesterol/triglyceride ratio was >0.57. CONCLUSIONS: LDL-C Plus assay represents a valid alternative to BQ for clinical laboratories.