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Soluble urokinase plasminogen activator receptor (suPAR) as an early predictor of severe respiratory failure in patients with COVID-19 pneumonia. Keywords: automation systems; SARS-CoV-2; soluble urokinase plasminogen activator receptor; suPAR EN automation systems SARS-CoV-2 soluble urokinase plasminogen activator receptor suPAR e33 e35 3 12/22/22 20230201 NES 230201 To the Editor, Medical laboratories undergo a continuous quality improvement process to increase efficiency and customer satisfaction and answer and meet clinical requests. Biochemical monitoring of COVID-19 patients through biomarkers has become critical for assessing disease severity and progression, monitoring therapeutic intervention as well as making treatment decisions using a precision medicine approach [[3]]. [Extracted from the article]

The role of chitinases has been focused as potential biomarkers in a wide number of inflammatory diseases, in monitoring active disease state, and predicting prognosis and response to therapies. The main chitinases, CHIT1 and YKL-40, are derived from 18 glycosyl hydrolases macrophage activation and play important roles in defense against chitin-containing pathogens and in food processing. Moreover, chitinases may have organ- as well as cell-specific effects in the context of infectious diseases and inflammatory disorders and able to induce tissue remodelling. The CHIT1 measurement is an easy, reproducible, reliable, and cost-effective affordable assay. The clinical use of CHIT1 for the screening of lysosomal storage disorders is quite practical, when proper cut-off values are determined for each laboratory. The potential of CHIT1 and chitinases has not been fully explored yet and future studies will produce many surprising discoveries in the immunology and allergology fields of research. However, since the presence of a null CHIT1 gene in a subpopulation would be responsible of false-negative values, the assay should be completed with the other markers such ACE and, if necessary, by genetic analysis when CHIT1 is unexpected low. [ABSTRACT FROM AUTHOR]

Keywords: ASPECT-PLUS sST2 assay; automation systems; heart failure; SEQUENT-IA™sST2 assay; Siemens ADVIA CHEMISTRY XPT EN ASPECT-PLUS sST2 assay automation systems heart failure SEQUENT-IA™sST2 assay Siemens ADVIA CHEMISTRY XPT e54 e56 3 01/07/22 20220115 NES 220115 To the Editor, During the last decade, several biomarkers alone or in combination involved in the development of HF have been studied to identify subgroups of patients at high risk of the worst outcome [[1]]. In all 385 patients, median sST2 plasma concentration was 24.98 ng/mL (range, 12.5-250 ng/mL; 25-75th percentiles, 19.43-51.94 ng/mL) measured by the ASPECT-PLUS ST2 assay and 25.11 ng/mL (range, 2.44-314.19 ng/mL; 25-75th percentiles, 18.08-52.78 ng/mL) by the SEQUENT-IA™ ST2 assay. [Extracted from the article]

The article presents an analytical performance of the method NT-proBNP assay on Advia Centaur XPT platform and to compare the results with the NT-proBNP method on the Dimension Vista LOCI platform. Topics discussed include information on the production of the brain natriuretic peptide (BPN) by ventricular myocardiocytes; discussions on the role of the BPN in the regulation of natriuresis, diuresis and vascular tone; and the use of the NT-proBNP for the evaluation of heart failure.

Background: The specificity of screening for congenital adrenal hyperplasia by direct measurement of 17-hydroxyprogesterone in filter paper dried blood spot samples by immunoassay is low and has a high false-positive rate. In order to reduce the false-positive rate of this test, we developed a rapid, robust, specific confirmatory procedure in which cortisol, 4-androstene-3,17-dione and 17-hydroxyprogesterone were measured simultaneously by ultra-performance liquid chromatography-tandem mass spectrometry. Methods: After extraction, samples were analysed by ultra-performance liquid chromatography-tandem mass spectrometry and 17-hydroxyprogesterone was quantified accurately. Other steroids were determined using stable deuterated internal standards. In total, 25 patient blood spot samples and 92 control samples were analysed. Results: The assay was linear for 17-hydroxyprogesterone, with a coefficient of determination >0.997 and imprecision ≤6.5%. An upper limit of normal for 17-hydroxyprogester-one of 4.45 nmol/L was established by analysing a cohort of samples from unaffected newborns. In addition, a cut-off of 3.5 for the peak areas ratio (17-hydroxyprogesterone+4-androstene-3,17-dione)/cortisol, allows confirmation of the affected steroidogenic enzyme. Conclusions: A high throughput method for the detection of steroids related to congenital adrenal hyperplasia has been developed, allowing the false-positive rate associated with screening for 17-hydroxyprogesterone by immunoassay to be determined. [ABSTRACT FROM AUTHOR]

The cerebrospinal fluid (CSF) is a key sample in the research for novel molecular biomarkers of neurodegenerative disorders. CSF represents a repertoire of neuro-secreted, biosynthesised and metabolised molecular products of the central nervous system (CNS). Diffusion of macromolecules from the peripheral circulatory system to the CSF is highly regulated by the blood-brain barrier, which prevents uncontrolled distribution of proteins in the CNS. The development of reproducible high resolution separations of proteins in 2-D electrophoresis methods by the advent of immobilised pH gradient has opened the route to multivariate holistic protein pattern investigation of CSF into neurodegenerative disorders. Moreover, the introduction of pre-fractionation techniques such as free flow electrophoresis is currently increasing the dynamic depth of proteome analysis. Alzheimer's disease (AD) and other forms of dementia, demyelinating diseases, Parkinson's disease (PD), and Creutzfeldt-Jakob disease (CJD) have been evaluated for biomarker discovery by CSF investigation in multiple studies. However, the statistical design of these clinical cross-sectional investigations remains a limited factor given the strong statistical power required for complex multivariate analysis. These initial evidences are of particular interest in dissecting specific molecular mechanisms. The development of fast and economic profiling of CSF by linear matrix assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF-MS) is providing a new ancillary technology to assess sample quality and pre-analytical requirements. In the following we take into account all these issues in the CSF proteomics investigation, especially highlighting the possible application in the development of clinical molecular biomarkers. Clin Chem Lab Med 2007;45:437–49. [ABSTRACT FROM AUTHOR]

Current clinical practice considers antinuclear anti- body (ANA) testing as a screening test; this has a major impact on laboratory work with a growing volume of analyses that need to be performed rapidly, to maintain good specificity and sensitivity. Ongoing discussions have been raised in order to identify the best technology to use in ANA screening, taking into account both clinical and economical implications. The aim of our study was to compare three different enzyme immunoassays (EIA) with immunofluorescence (IF) assay in order to identify which test is better for use as a screening test. The study was performed on 473 sera and the three different EIA tests were based on nuclear homogenates from HeLa cells, purified antigens from HEp-2 cells and recombinant antigens, respectively. The concordance between EIA- ANA and IF-ANA techniques, determined by the Κ statistic, was acceptable, but not complete, and discrepancies between both EIA-positive/IF-negative samples and IF-positive/EIA-negative were found. Both methods show interesting diagnostic abilities, however, the IF-ANA assay seems to be the first choice test in a well-standardized immunofluorescence laboratory with experienced microscopists, whereas the EIA test might be useful especially in large-scale ANA screening. [ABSTRACT FROM AUTHOR]

Bile acids play a pivotal role in the metabolism of cholesterol and lipids. Their blood concentrations are important prognostic and diagnostic indicators of hepatobiliary and intestinal dysfunction. This class of molecules comprises a heterogeneous group of compounds with a common cholesterol scaffold. Recently, the introduction of liquid chromatography coupled to tandem mass spectrometry methods has revealed an innovative path in the quantisation of specific bile acids in biological specimens. A robust and sensitive method has been developed based on high performance liquid chromatography separation coupled to an electrospray triple-quadrupole mass spectrometer. Human plasma samples were analysed on a C18 reverse-phase column. The elution profiles were monitored in multiple reaction-monitoring mode, quantifying and identifying each analyte by its own unique precursor to product patterns. A linear correlation over a broad range of bile acid concentrations (0.1-100 µM) was observed. The average recovery period for all of the analysed bile acids was 98±3%. Intra-day and inter-day precision averages were 2% and 5.4%, respectively. The determination was achieved within a single chromatographic run for all unconjugated, glycineand taurine-conjugated isomeric forms of bile acids. As a proof of principle this method has been validated on a small subset of cholestatic patients (n = 7) and compared to appropriate clinical controls (n = 10). Based upon our encouraging experimental results, the described HPLC separation coupled to tandem mass spectrometry method for the analysis of bile acids in biological samples is deemed a robust and accurate procedure. Consequently, we propose this technique as a suitable candidate method for the identification and quantitation of bile acids in routine analysis. [ABSTRACT FROM AUTHOR]