A multicentre analysis of four low-density lipoprotein cholesterol direct assays in samples with extreme high-density lipoprotein cholesterol concentrations.

Background: Although LDL-C has been traditionally estimated using the Friedewald formula (FF), several direct homogeneous assays have been developed to overcome the limitations of this formula and the complicated manual procedure required in the reference method. However, several differences have been reported between these assays in certain situations.

Methods: Two groups of 105 samples with extreme low and high HDL-C concentrations were processed, employing four different instruments and with the reagents for total cholesterol, triglycerides, HDL-C and LDL-C provided by the distinct manufacturers.

[Diagnostic and prognostic power of biomarkers to improve the management of community acquired pneumonia in the emergency department].

Objectives: To analyse the usefulness and performance of several biomarkers [C-reactive protein (CRP), mid-regional pro-adrenomedullin (MR-proADM), procalcitonin (PCT)] and lactate in predicting short- and medium-term mortality compared with the prognostic severity scales (PSS) usually employed for community-acquired pneumonia (CAP) and in assessing the aetiological suspicion of infection by Streptococcus pneumoniae and bacteraemia.

Methods: Observational, prospective and analytical study was conducted on patients who were diagnosed with CAP in our emergency department (ED). The data collected included socio-demographic and comorbidity variables, Charlson index, priority level according to the Spanish Triage System (STS), stage in the Pneumonia Severity Index (PSI) and in the CURB-65 (confusion, urea, respiratory rate, blood pressure and age ≥65years), criteria of severe CAP, microbiological studies, and biomarkers determinations.

[Ability of procalcitonin to predict bacteremia in patients with community acquired pneumonia].

Background And Objective: To analyze the usefulness and ability of procalcitonin (PCT) to predict the presence of bacteremia in patients with community-acquired pneumonia (CAP) caused by Streptococcus pneumoniae (S. pneumoniae) or other bacteria.

Patients And Method: This is an observational, prospective and descriptive study involving patients who were diagnosed with CAP in our Emergency Department.

Biological variation and reference change values of common clinical chemistry and haematologic laboratory analytes in the elderly population.

Background: Biological variation (BV) and reference change values (RCVs) have been widely described for the general population, but the use of these data derived from adults in the elderly population is a controversial issue. We determined the within- and between-subject BV and RCV in both elderly and young people and compared them with previously published analyses.

Methods: Samples were collected from 135 volunteers over 80 years of age at weekly intervals over 4 weeks.

A proposed reference change value for an IgA anti-tissue transglutaminase immunoassay to improve interpretation of serial results in celiac patients.

Background: Celiac disease (CD) is an autoimmune disorder caused by an inappropriate immunological response to gluten ingestion in genetically susceptible individuals. IgA anti-tissue transglutaminase (tTG) antibodies have been widely employed as a specific biochemical marker for CD. Recent studies have also shown its usefulness in evaluating patient compliance with a gluten-free diet.

Extreme concentrations of high density lipoprotein cholesterol affect the calculation of low density lipoprotein cholesterol in the Friedewald formula and other proposed formulas.

Objectives: To investigate the effect of extreme levels of high density lipoprotein cholesterol (HDL-C) in the calculation of low density lipoprotein cholesterol (LDL-C) using Friedewald's formula (FF) and other formulas proposed recently.

Design And Methods: Lipoprotein profile was performed in 2603 samples with HDL-C ≤ 20 mg/dL and 1953 samples with HDL-C ≥ 100 mg/dL.

Results: Wilcoxon's and Student's t-tests showed significant differences (p<0.