Lack of transferability between different immunoassays and LC-MS/MS for total 25-hydroxyvitamin D measurement and disagreement defining deficiency.

BACKGROUND: Over the last few years, it has become much more common to measure concentrations of vitamin D, as its deficiency has been associated with an increasing number of health problems. Recently, a number of new immunoassays for measurement of total 25-hydroxyvitamin D (25OH-D) concentration have been released but their results may not be transferable. METHODS: Our main objective was to compare results from the Cobas(®) e411 (Roche Diagnostics), Advia Centaur(®) (Siemens), Architect (Abbott), IDS-iSYS (Vitro S.A.), and Liaison(®) (Diasorin) immunoassay systems with each other and with liquid chromatography-tandem mass spectrometry (LC-MS/MS). We obtained 184 routine serum samples, covering the whole measuring range, for these methods. RESULTS: Kappa values above 0.8 were considered to indicate excellent agreement. With a cut-off of 50 nmol/L Architect and Cobas were the only immunoassay methods able to identify patients with deficiencies consistent with the findings of the reference method LC-MS/MS. On the other hand, using a cut-off of 37.5 nmol/L for Liaison and 75 nmol/L for IDS-iSYS, while maintaining the value of 50 nmol/L for the LC-MS/MS method, kappa values of 0.80 and 0.83 respectively were obtained. CONCLUSIONS: Choosing the best method for each laboratory is challenging due to methodological differences between them and 50 nmol/L cannot be considered as a general cut-off for defining hypovitaminosis.

Proteína C reactiva, procalcitonina y proadrenomedulina en la evolución de neumonías hospitalizadas / C reactive protein, procalcitonin and proadrenomedullin in the outcome of hospitalized pneumonia patients

Introducción. La neumonía adquirida en la comunidad (NAC) sigue siendo un problema sanitario importante. Para establecer su gravedad existen una serie de escalas de severidad, pero tienen sus limitaciones. Se han propuesto diferentes biomarcadores que podrían resultar de ayuda. Objetivo. Evaluar el valor pronóstico de proteína C reactiva (PCR), procalcitonina (PCT) y proadrenomedulina (PADM) para predecir mala evolución intrahospitalaria en NAC. Material y métodos. Se incluyeron todos los pacientes diagnosticados de NAC que quedaron ingresados durante un periodo de 13 meses. Se congeló a −80°C suero y plasma EDTA obtenidos en el Servicio de Urgencias del Hospital para la determinación de los biomarcadores. Se dividió a los pacientes en dos grupos: los que evolucionaron favorablemente y los que tuvieron mala evolución. Los datos clínicos de los pacientes fueron recopilados por revisión de la historia clínica. Resultados. Las diferencias de las medianas de los tres biomarcadores para los dos grupos adquirieron significación estadística. Las áreas bajo la curva de las curvas ROC correspondientes fueron: 0,67 para PCT, 0,62 para PCR y 0,74 para PADM. Los puntos de corte seleccionados con sus respectivos datos de sensibilidad y especificidad fueron: para PCT 0,5 ng/mL (S: 0,67/E: 0,61), para PCR 150mg/L (S: 0,67/E: 0,47) y para PADM 1,2 nmol/L (S: 0,80/E: 0,53). Conclusiones. Los resultados sugieren un posible valor pronóstico de estos biomarcadores en relación con la evolución intrahospitalaria que presentarán los pacientes con NAC, destacando entre ellos la PADM (AU)

Introduction: Community-acquired pneumonia (CAP) continues to be a major health problem. There are several scoring systems to predict its severity, but they have limitations. Different biomarkers have been proposed to be of assistance. Objective: To evaluate C reactive protein (CRP), procalcitonin (PCT) and proadrenomedullin (PADM) as prognostic factors to predict the outcome in CAP. Material and methods: All patients diagnosed with CAP and admitted to hospital during a period of 13 months were included in our study. Serum and EDTA plasma samples from the Emergency Unit were collected and frozen at -80 ◦C for biomarkers determination. Patients were divided into two groups: those who developed favorably and those with an unfavorable outcome. Clinical data for these patients were collected by reviewing their medical records. Results: The median values between both groups were found to be statistically significantly different for all three biomarkers. Areas under the ROC curve for each biomarker were: 0.67 for PCT, 0.62 for CRP and 0.74 for PADM. Selected cut-off for each biomarker with their corresponding sensitivity and specificity values were: 0.5 ng/mL (Se: 0.67/Sp: 0.61) for PCT, 150 mg/L (Se: 0.67/Sp: 0.47) for CRP and 1.2 nmol/L (Se: 0.8/Sp: 0.53) for PADM. Conclusions: The results indicate that these biomarkers could help in predicting the outcome of patients with CAP during hospitalization, with PADM being a potentially better predictor (AU)