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    23668 results match your criteria Clinical Chemistry[Journal]

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    Ultrasensitive Detection of Chimerism by Single-Molecule Molecular Inversion Probe Capture and High-Throughput Sequencing of Copy Number Deletion Polymorphisms.
    Clin Chem 2018 Mar 16. Epub 2018 Mar 16.
    Department of Laboratory Medicine, University of Washington, Seattle, WA.
    Background: Genomic chimerism, the co-occurrence of cells from different genetic origins, provides important diagnostic information in diverse clinical contexts, including graft injury detection and longitudinal surveillance of hematopoietic stem cell transplantation patients, but existing assays are limiting. Here we applied single-molecule molecular inversion probes (smMIPs), a high-throughput sequencing technology combining multiplexed target capture with read quantification mediated by unique molecular identifiers, to detect chimerism based on the presence or absence of polymorphic genomic loci.

    Methods: We designed a 159-smMIP panel targeting 40 autosomal regions of frequent homozygous deletion across human populations and 2 sex-linked loci. Read More

    Advanced Whole-Genome Sequencing and Analysis of Fetal Genomes from Amniotic Fluid.
    Clin Chem 2018 Mar 15. Epub 2018 Mar 15.
    Advanced Genomics Technology Lab, Complete Genomics, Inc., San Jose, CA;
    Background: Amniocentesis is a common procedure, the primary purpose of which is to collect cells from the fetus to allow testing for abnormal chromosomes, altered chromosomal copy number, or a small number of genes that have small single- to multibase defects. Here we demonstrate the feasibility of generating an accurate whole-genome sequence of a fetus from either the cellular or cell-free DNA (cfDNA) of an amniotic sample.

    Methods: cfDNA and DNA isolated from the cell pellet of 31 amniocenteses were sequenced to approximately 50× genome coverage by use of the Complete Genomics nanoarray platform. Read More

    Neurogranin as Cerebrospinal Fluid Biomarker for Alzheimer Disease: An Assay Comparison Study.
    Clin Chem 2018 Mar 9. Epub 2018 Mar 9.
    Neurochemistry laboratory, Department of Clinical Chemistry, Amsterdam Neuroscience, VU University Medical Center Amsterdam, the Netherlands.
    Background: Neurogranin in cerebrospinal fluid (CSF) correlates with cognitive decline and is a potential novel biomarker for Alzheimer disease (AD) dementia. We investigated the analytical and diagnostic performance of 3 commonly used neurogranin assays in the same cohort of patients to improve the interpretability of CSF neurogranin test results.

    Methods: The neurogranin Singulex assay from Washington University, St. Read More

    Complement C3 and Risk of Diabetic Microvascular Disease: A Cohort Study of 95202 Individuals from the General Population.
    Clin Chem 2018 Mar 9. Epub 2018 Mar 9.
    Department of Clinical Biochemistry, Herlev and Gentofte Hospital, Copenhagen University Hospital, Faculty of Health and Medical Sciences, University of Copenhagen, Herlev, Denmark.
    Background: Whether the complement system is involved in the development of diabetic microvascular disease is unknown. We tested the hypothesis that high concentrations of complement C3 are associated with increased risk of diabetic retinopathy, nephropathy, and neuropathy in individuals from the general population.

    Methods: We studied 95202 individuals from the general population with baseline measurements of complement C3, genotyped for rs1065489, rs429608, and rs448260 determining concentrations of complement C3, and enrolled in the Copenhagen General Population Study from 2003 through 2013, following them until April 10, 2013. Read More

    Liquid Profiling of Circulating Tumor DNA in Plasma of Melanoma Patients for Companion Diagnostics and Monitoring ofInhibitor Therapy.
    Clin Chem 2018 Feb 26. Epub 2018 Feb 26.
    Department of Clinical Chemistry, University Medical Centre, Ruprecht-Karls University of Heidelberg, Mannheim, Germany;
    Background: The current standard for determining eligibility of patients with metastatic melanoma for-targeted therapy is tissue-based testing ofmutations. As patients are rarely rebiopsied, detection in blood might be advantageous by enabling a comprehensive assessment of tumor mutational status in real time and thereby representing a noninvasive biomarker for monitoringtherapy.

    Methods: In all, 634 stage I to IV melanoma patients were enrolled at 2 centers, and 1406 plasma samples were prospectively collected. Read More

    Twenty-four-Hour Biological Variation of Creatinine, Cystatin C, and Estimated Glomerular Filtration Rate in People With or Without Chronic Kidney Disease.
    Clin Chem 2018 Feb 26. Epub 2018 Feb 26.
    Department of Clinical Chemistry, Central Diagnostic Laboratory, Maastricht University Medical Center, Maastricht, the Netherlands;
    Background: Estimated glomerular filtration rate (eGFR) is widely used in clinical practice. This study assessed the within-subject biological variation (CV) of different eGFR equations in people with chronic kidney disease (CKD) and people without CKD. The aims of this study were () to determine the 24-h biological variation profiles of creatinine, cystatin C, and eGFR and () to determine whether CVof creatinine, cystatin C, and eGFR changes on deterioration of glomerular filtration. Read More

    Comparison of Generic Fluorescent Markers for Detection of Extracellular Vesicles by Flow Cytometry.
    Clin Chem 2018 Feb 16. Epub 2018 Feb 16.
    Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands.
    Background: Extracellular vesicles (EVs) in biofluids are potential biomarkers of disease. To explore the clinical relevance of EVs, a specific generic EV marker would be useful, one that does not require antibodies and binds to all EVs. Here we evaluated 5 commonly used generic markers for flow cytometry. Read More

    The Effect of Single Mismatches on Primer Extension.
    Clin Chem 2018 Feb 14. Epub 2018 Feb 14.
    Department of Pathology, University of Utah Health Sciences Center, Salt Lake City, UT.
    Background: Allele-specific PCR is an important diagnostic tool that identifies single-nucleotide variants by preferential amplification of a particular allele, using primers that are mismatched to all but one allele variant.

    Methods: We applied a fluorescent stopped-flow polymerase assay to measure extension rates from oligonucleotide hairpins to simulate primer-template pairs. Under PCR-applicable conditions, reaction rates were recorded in nucleotides per second per polymerase (nt/s/poly). Read More

    Advances in the Diagnosis and Management of Cystic Fibrosis in the Genomic Era.
    Clin Chem 2018 Feb 7. Epub 2018 Feb 7.
    Department of Pathology, Medical College of Wisconsin and Department of Pathology and Laboratory Medicine, Children's Hospital of Wisconsin, Milwaukee, WI.
    Background: Cystic fibrosis (CF) is a complex autosomal recessive disease that continues to present unique diagnostic challenges. Because CF was first described in 1938, there has been a substantial growth of genetic and phenotypic information about the disorder. During the past few years, as more evidence has become available, a consortium of international experts determined that the 2008 guidelines from the CF Foundation needed to be reviewed and updated. Read More

    Establishment of Community-Based Reference Intervals for Fructosamine, Glycated Albumin, and 1,5-Anhydroglucitol.
    Clin Chem 2018 Feb 7. Epub 2018 Feb 7.
    Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN.
    Background: There is growing interest in fructosamine, glycated albumin, and 1,5-anhydroglucitol (1,5-AG) as alternative measures of hyperglycemia, particularly for use in settings where traditional measures (glucose and HbA1c) are problematic or where intermediate (2-4 weeks) glycemic control is of interest. However, reference intervals for these alternative biomarkers are not established.

    Methods: We measured fructosamine, glycated albumin, and 1,5-AG in a community-based sample of US black and white adults who participated in the Atherosclerosis Risk in Communities (ARIC) Study. Read More

    Evaluating Rapid Rule-out of Acute Myocardial Infarction by Use of a High-Sensitivity Cardiac Troponin I Assay at Presentation.
    Clin Chem 2018 Feb 1. Epub 2018 Feb 1.
    Royal Brisbane and Women's Hospital, Herston, Australia.
    Background: Low concentrations of cardiac troponin (cTn) have been recommended for rapid rule-out of acute myocardial infarction (AMI). We examined the Beckman Coulter Access high-sensitivity cardiac troponin I (hs-cTnI) assay to identify a single test threshold that can safely rule out AMI.

    Methods: This analysis used stored samples collected in 2 prospective observational studies. Read More

    Resolution of Spurious Immunonephelometric IgG Subclass Measurement Discrepancies by LC-MS/MS.
    Clin Chem 2018 Jan 19. Epub 2018 Jan 19.
    Department of Pathology and Laboratory Medicine, St. Paul's Hospital, Vancouver, BC, Canada;
    Background: The Binding Site immunonephelometric (IN) IgG subclass reagents (IgG1, IgG2, IgG3, IgG4, BSIN) are used for assessment of both immunodeficiency and IgG4-related disease (IgG4-RD). In our laboratory, suspected analytic errors were noted in patients with increases in IgG4: The sum of the individual IgG subclasses was substantially greater than the measured total IgG concentrations (unlike samples with normal IgG4), and the IgG4 concentration was always less than the IgG2 concentration.

    Methods: We developed a tryptic digest LC-MS/MS method to quantify IgG1, IgG2, IgG3, and IgG4 in serum. Read More

    Prognostic Implications of Multiplex Detection ofMutations in Cell-Free DNA from Patients with Pancreatic Ductal Adenocarcinoma.
    Clin Chem 2018 Jan 19. Epub 2018 Jan 19.
    Translational Cancer Research Branch, Division of Translational Science, National Cancer Center, Goyang, Korea;
    Background: Cell-free DNA (cfDNA) is known to provide potential biomarkers for predicting clinical outcome, but its value in pancreatic ductal adenocarcinoma (PDAC) has not been fully evaluated. The aim of this study was to evaluate the clinical applicability of quantitative analysis of multiplexmutations in cell-free DNA from patients with PDAC.

    Methods: A total of 106 patients with PDAC were enrolled in this prospective study. Read More

    Clinical Evaluation of a Blood Assay to Diagnose Paucibacillary Tuberculosis Via Bacterial Antigens.
    Clin Chem 2018 Jan 18. Epub 2018 Jan 18.
    Virginia G. Piper Biodesign Center for Personalized Diagnostics, The Biodesign Institute, Arizona State University, Tempe, AZ;
    Background: The diagnosis of active tuberculosis (TB)cases primarily relies on methods that detect() bacilli or their DNA in patient samples (e.g., mycobacterial culture and Xpert MTB/RIF assays), but these tests have low clinical sensitivity for patients with paucibacillary TB disease. Read More

    IFCC Working Group Recommendations for Assessing Commutability Part 2: Using the Difference in Bias between a Reference Material and Clinical Samples.
    Clin Chem 2018 Mar 18;64(3):455-464. Epub 2018 Jan 18.
    Department of Pathology, Virginia Commonwealth University, Richmond, VA.
    A process is described to assess the commutability of a reference material (RM) intended for use as a calibrator, trueness control, or external quality assessment sample based on the difference in bias between an RM and clinical samples (CSs) measured using 2 different measurement procedures (MPs). This difference in bias is compared with a criterion based on a medically relevant difference between an RM and CS results to make a conclusion regarding commutability. When more than 2 MPs are included, the commutability is assessed pairwise for all combinations of 2 MPs. Read More

    IFCC Working Group Recommendations for Assessing Commutability Part 3: Using the Calibration Effectiveness of a Reference Material.
    Clin Chem 2018 Mar 18;64(3):465-474. Epub 2018 Jan 18.
    Department of Pathology, Virginia Commonwealth University, Richmond, VA.
    A process is described to assess the commutability of a reference material (RM) intended for use as a calibrator based on its ability to fulfill its intended use in a calibration traceability scheme to produce equivalent clinical sample (CS) results among different measurement procedures (MPs) for the same measurand. Three sources of systematic error are elucidated in the context of creating the calibration model for translating MP signals to measurand amounts: calibration fit, calibrator level trueness, and commutability. An example set of 40 CS results from 7 MPs is used to illustrate estimation of bias and variability for each MP. Read More

    IFCC Working Group Recommendations for Assessing Commutability Part 1: General Experimental Design.
    Clin Chem 2018 Mar 18;64(3):447-454. Epub 2018 Jan 18.
    Centers for Disease Control and Prevention, Atlanta, GA.
    Commutability is a property of a reference material (RM) that relates to the closeness of agreement between results for an RM and results for clinical samples (CSs) when measured by ≥2 measurement procedures (MPs). Commutability of RMs used in a calibration traceability scheme is an essential property for them to be fit for purpose. Similarly, commutability of trueness controls or external quality assessment samples is essential when those materials are used to assess trueness of results for CSs. Read More

    Effect of Acute Coronary Syndrome Probability on Diagnostic and Prognostic Performance of High-Sensitivity Cardiac Troponin.
    Clin Chem 2018 Mar 17;64(3):515-525. Epub 2018 Jan 17.
    Cardiovascular Research Institute Basel (CRIB) and Department of Cardiology, University Hospital Basel, University of Basel, Basel, Switzerland;
    Background: There is concern that high-sensitivity cardiac troponin (hs-cTn) may have low diagnostic accuracy in patients with low acute coronary syndrome (ACS) probability.

    Methods: We prospectively stratified patients presenting with acute chest discomfort to the emergency department (ED) into 3 groups according to their probability for ACS as assessed by the treating ED physician using a visual analog scale: ≤10%, 11% to 79%, and ≥80%, reviewing all information available at 90 min. hs-cTnT and hs-cTnI concentrations were determined in a blinded fashion. Read More

    Clinical Laboratory Practice Recommendations for the Use of Cardiac Troponin in Acute Coronary Syndrome: Expert Opinion from the Academy of the American Association for Clinical Chemistry and the Task Force on Clinical Applications of Cardiac Bio-Markers of the International Federation of Clinical Chemistry and Laboratory Medicine.
    Clin Chem 2018 Jan 17. Epub 2018 Jan 17.
    Department of Laboratory Medicine and Pathology, Hennepin County Medical Center and University of Minnesota, Minneapolis, MN.
    This document is an essential companion to the third iteration of the National Academy of Clinical Biochemistry [NACB,now the American Association for Clinical Chemistry (AACC) Academy] Laboratory Medicine Practice Guidelines (LMPG) on cardiac markers. The expert consensus recommendations were drafted in collaboration with the International Federation of Clinical Chemistry and Laboratory Medicine Task Force on Clinical Applications of Bio-Markers (IFCC TF-CB). We determined that there is sufficient clinical guidance on the use of cardiac troponin (cTn) testing from clinical practice groups. Read More

    Specific Substrate for the Assay of Lysosomal Acid Lipase.
    Clin Chem 2018 Jan 16. Epub 2018 Jan 16.
    Department of Chemistry, University of Washington, Seattle, WA;
    Background: Deficiency of lysosomal acid lipase (LAL) causes Wolman disease and cholesterol ester storage disease. With the recent introduction of enzyme replacement therapy to manage LAL deficiency comes the need for a reliable assay of LAL enzymatic activity that can be applied to dried blood spots (DBS).

    Methods: We prepared and tested a library of analogs of palmitoyl 4-methylumbelifferyl esters to find a highly active and specific substrate for LAL in DBS. Read More

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