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Abstract

Objectives

Non-invasive prenatal screening (NIPS) is a test for the detection of major fetal chromosomal abnormalities in maternal blood during pregnancy. The purpose of this study was to assess the performance of NIPS implemented within the framework of the Screening Program for Congenital Abnormalities of the Andalusian Health System.

Methods

A retrospective observational study was undertaken to determine the number of NIPS tests performed since its introduction. The number of invasive diagnostic tests done after the implementation of NIPS in the patients included in the program between March 2016 and August 2017 was also quantified.

Results

A total of 6,258 combined first- and second trimester screening tests were performed, covering 95% of the population. In total, 250 subjects were identified as high risk, of whom 200 underwent NIPS after loss to follow-up. NIPS showed a sensitivity of 100% (95% CI: 76.84–100%) and a specificity of 99.46% (95% CI: 97.04–99.99%).

Conclusions

This test has proven to have a very high sensitivity and specificity. The results obtained demonstrate that the incorporation of NIPS in clinical practice minimizes the rate of miscarriages and reduces the frequency of invasive procedures by 70%.

Resumen

El eje hipotálamo-hipófiso-testicular es activo en la vida fetal y durante los primeros meses de la vida posnatal: la hipófisis secreta hormona luteinizante (LH) y folículo-estimulante (FSH), mientras que el testículo produce testosterona y factor insulino-símil 3 (INSL3) en las células de Leydig y hormona anti-Mülleriana (AMH) e inhibina B en las células de Sertoli. En la infancia, los niveles séricos de gonadotrofinas, testosterona y factor INSL3 disminuyen a valores prácticamente indetectables, pero los de AMH e inhibina B permanecen altos. En la pubertad, se reactivan las gonadotrofinas y la producción de testosterona e INSL3, aumenta la inhibina y disminuye la AMH, como signo de maduración de la célula de Sertoli. Sobre la base del conocimiento de la fisiología del desarrollo del eje, es posible utilizar clínicamente estos biomarcadores para interpretar la fisiopatología y diagnosticar las diferentes formas de hipogonadismo que pueden presentarse en la infancia y la adolescencia.

Abstract

Objectives

The objective of this review was to characterize the use of biomarkers of male hypogonadism in childhood and adolescence.

Contents

The hypothalamic-pituitary-gonadal (HPG) axis is active during fetal life and over the first months of postnatal life. The pituitary gland secretes follicle stimulating hormone (FSH) and luteinizing hormone (LH), whereas the testes induce Leydig cells to produce testosterone and insulin-like factor 3 (INSL), and drive Sertoli cells to secrete anti-Müllerian hormone (AMH) and inhibin B. During childhood, serum levels of gonadotropins, testosterone and insulin-like 3 (INSL3) decline to undetectable levels, whereas levels of AMH and inhibin B remain high. During puberty, the production of gonadotropins, testosterone, and INSL3 is reactivated, inhibin B increases, and AMH decreases as a sign of Sertoli cell maturation.

Summary and outlook

Based on our knowledge of the developmental physiology of the HPG axis, these biomarkers can be used in clinical practice to interpret the physiopathology of hypogonadism. Additionally, these markers can have diagnostic value in different forms of hypogonadism that may appear during childhood and adolescence.

Resumen

Objetivos

Demostrar la importancia de la realización del estudio del sedimento urinario con la correcta interpretación y tipificación de los cristales como herramienta diagnóstica en el laboratorio clínico, así como de la elaboración de protocolos que determinen la necesidad de realizar este tipo de exámenes microscópicos de sedimento urinario de forma rutinaria.

Caso clínico

Se trata de un paciente varón de edad avanzada sin antecedentes personales ni familiares de interés. Se presenta con dolor fijo y sin irradiar de tres días de duración en fosa iliaca izquierda, siendo la primera que vez que padece episodios de dolor de este tipo. El sistemático de orina revela proteinuria, hematuria y el sedimento muestra abundantes cristales hexagonales y planos, típicos de cistina. El análisis de aminoácidos confirma el hallazgo encontrándose concentraciones elevadas de aminoácidos aminoácidos dibásicos y de cistina.

Conclusiónes

El estudio del sedimento urinario por parte del laboratorio clínico pone de manifiesto la presencia de un caso de cistinuria por la aparición en él de cristales patognomónicos de dicha patología en una edad avanzada y sin antecedentes previos. Este caso clínico tiene especial interés al demostrar la importancia del sedimento urinario como herramienta diagnóstica en la evaluación de una enfermedad genética, que se pone de manifiesto como un simple cólico nefrítico.

Abstract

Objectives

To demonstrate the importance of carrying out the urinary sediment study with the correct interpretation and crystals typification as a clinical laboratory diagnostic tool, as well as the elaboration of protocols that determine the need to realize this type of microscopic urinary sediment examination routinely.

Case presentation

Elderly male patient with no personal or family history of interest that presented with left iliac fossa fixed and non-irradiated pain lasting three days. This is the first time that he suffered pain episodes of this type. The urine analysis reveals proteinuria, hematuria and the sediment shows abundant flat and hexagonal crystals, typical of cystine. Amino acid analysis confirms the finding, showing high dibasic amino acids and cystine concentrations.

Conclusions

The study of the urinary sediment by the clinical laboratory reveals the presence of a case of cystinuria due to the appearance of their pathognomonic crystals at an advanced age and without a previous history. The case reported in this paper is of interest for clinical laboratory practice, as it demonstrates the utility of urine sediment examination in the diagnosis of a genetic disease that manifests as a simple renal colic.

Resumen

Objetivos

Existen multitud de estudios de estabilidad de magnitudes de interés clínico, aunque con resultados muy diferentes o incluso contradictorios, como es el caso de la alanina aminotransferasa (ALT). El objetivo de este estudio fue evaluar la estabilidad de la ALT en suero incluyendo múltiples variables.

Métodos

Se realizó un estudio multicéntrico en ocho laboratorios, con muestras de suero con concentración catalítica inicial conocida de ALT, en cuatro intervalos diferentes: <50 U/L (<0.83 μkat/L), 50–200 U/L (0.83–3.33 μkat/L), 200–400 U/L (3.33–6.67 μkat/L) y >400 U/L (>6.67 μkat/L). Se conservaron las muestras durante siete días a dos temperaturas diferentes, siguiendo cuatro modelos experimentales y utilizando cuatro plataformas analíticas diferentes. Se calcularon las respectivas ecuaciones de estabilidad mediante regresión lineal y se valoró la influencia de las diferentes variables en un modelo multivariante.

Resultados

Se observó una disminución constante de la concentración catalítica de la ALT respecto al tiempo. Asimismo, se observó un marcado efecto de la temperatura y de la plataforma analítica utilizada (−4%/día a temperatura ambiente frente a −1%/día refrigerado), con una mayor inestabilidad en Architect (Abbott). Se detectó un ligero efecto de la concentración catalítica inicial de ALT, sin embargo, no se observó influencia del modelo experimental utilizado.

Conclusiónes

La ALT en suero sufre una disminución constante en el tiempo que se mitiga con la refrigeración de la muestra. Se ha encontrado un efecto significativo de variables poco estudiadas que, unidas a una gran variabilidad interindividual, hacen necesarios estudios con un alto número de muestras para determinar las ecuaciones de estabilidad.

Abstract

Objectives

The stability of the analytes most commonly used in routine clinical practice has been the subject of intensive research, with varying and even conflicting results. Such is the case of alanine aminotransferase (ALT). The purpose of this study was to determine the stability of serum ALT according to different variables.

Methods

A multicentric study was conducted in eight laboratories using serum samples with known initial catalytic concentrations of ALT within four different ranges, namely: <50 U/L (<0.83 μkat/L), 50–200 U/L (0.83–3.33 μkat/L), 200–400 U/L (3.33–6.67 μkat/L) and >400 U/L (>6.67 μkat/L). Samples were stored for seven days at two different temperatures using four experimental models and four laboratory analytical platforms. The respective stability equations were calculated by linear regression. A multivariate model was used to assess the influence of different variables.

Results

Catalytic concentrations of ALT decreased gradually over time. Temperature (−4%/day at room temperature vs. −1%/day under refrigeration) and the analytical platform had a significant impact, with Architect (Abbott) showing the greatest instability. Initial catalytic concentrations of ALT only had a slight impact on stability, whereas the experimental model had no impact at all.

Conclusions

The constant decrease in serum ALT is reduced when refrigerated. Scarcely studied variables were found to have a significant impact on ALT stability. This observation, added to a considerable inter-individual variability, makes larger studies necessary for the definition of stability equations.