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1.
Can J Cardiol ; 2024 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-38336003

RESUMO

Detecting dyslipidemia early is important because atherosclerosis originates in childhood and early treatment can improve outcomes. In 2022, the Canadian Cardiovascular Society (CCS) and Canadian Pediatric Cardiology Association (CPCA) published a clinical practice update to detect, evaluate, and manage pediatric dyslipidemia. However, guidance on its translation into clinical laboratories is lacking. The Canadian Society of Clinical Chemists Working Group on Reference Interval Harmonization Lipid Team aims to assist guideline implementation and promote harmonized pediatric lipid reporting across Canada. The 2022 CCS/CPCA clinical practice update, 2011 National Heart, Lung, and Blood Institute integrated guidelines, and new data analysis (Canadian pediatric reference values from the Canadian Laboratory Initiative on Pediatric Reference Intervals [CALIPER] and retrospective patient data from large community laboratories) were incorporated to develop 5 key recommendations. These include recommendations to: (1) offer nonfasting and fasting lipid testing; (2) offer a lipid panel including total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), non-HDL-C, and triglycerides, with apolipoprotein B and lipoprotein(a) available as individually orderable tests; (3) flag total cholesterol, LDL-C, and non-HDL-C results ≥ 95th percentile, and HDL-C results < 10th percentile, as recommended by CCS/CPCA/National Heart, Lung, and Blood Institute and validated by CALIPER, and flag apolipoprotein B and nonfasting triglyceride results ≥ 95th percentile on the basis of CALIPER, and do not flag Lp(a) results but mention the adult cutoff in the interpretive comments; (4) implement interpretive comments listed in the current report; and (5) implement the National Institutes of Health LDL-C equation. The Canadian Society of Clinical Chemists Working Group on Reference Interval Harmonization Lipid Team will support clinical laboratories to implement these recommendations using knowledge translation strategies. Harmonizing pediatric lipid reporting across Canadian clinical laboratories will optimize clinical decision-making and improve cardiovascular risk management in youth.

2.
Lab Med ; 2024 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-38417046

RESUMO

BACKGROUND: Despite stewardship efforts, laboratory testing overuse persists across medicine. OBJECTIVES: To understand laboratory stewardship perceptions and testing patterns at a tertiary care pediatric hospital so that we could identify potential improvement opportunities. METHODS: An electronic survey exploring laboratory stewardship was sent to all pediatric medicine resident and staff physicians. Laboratory testing data were also assessed for patterns of testing and overuse. RESULTS: The survey response rate was 54% (43/80). The results indicated good familiarity with stewardship but poor familiarity with testing specifics (eg, cost). A mobile reference application was the most preferred quality improvement intervention, and online modules were the least desired. Overuse was apparent, with as many as 53% of laboratory tests being repeated within 7 days and only half of repeated tests subsequently yielding abnormal results. CONCLUSIONS: Altogether, the data we collated demonstrated poor understanding of laboratory stewardship and substantial repeat testing with few abnormal results. These study findings suggest that laboratory stewardship is lacking at our center, and that multiple improvement opportunities exist.

3.
Clin Chem Lab Med ; 61(12): 2094-2101, 2023 11 27.
Artigo em Inglês | MEDLINE | ID: mdl-37327359

RESUMO

OBJECTIVES: The trueness and precision of clinical laboratory results are ensured through total quality management systems (TQM), which primarily include internal quality control (IQC) practices. However, quality practices vary globally. To understand the current global state of IQC practice and IQC management in relation to TQM the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) Task Force on Global Laboratory Quality (TF-GLQ) conducted a survey of IFCC member countries on IQC practices and management. METHODS: The survey included 16 questions regarding IQC and laboratory TQM practices and was distributed to IFCC full and affiliate member countries (n=110). A total of 46 (41.8 %) responses were received from all regions except North America. RESULTS: Of the responding countries, 78.3 % (n=36) had legislative regulations or accreditation requirements governing medical laboratory quality standards. However, implementation was not mandatory in 46.7 % (n=21) of responding countries. IQC practices varied considerably with 57.1 % (n=28) of respondents indicating that they run 2 levels of IQC, 66.7 % (n=24) indicating they run IQC every 24 h and 66.7 % (n=28) using assay manufacturer IQC material sources. Only 29.3 % (n=12) of respondents indicated that every medical laboratory in their country has written IQC policies and procedures. By contrast, 97.6 % (n=40) of responding countries indicated they take corrective action and result remediation in the event of IQC failure. CONCLUSIONS: The variability in TQM and IQC practices highlights the need for more formal programs and education to standardize and improve TQM in medical laboratories.


Assuntos
Laboratórios , Gestão da Qualidade Total , Humanos , Controle de Qualidade , Inquéritos e Questionários
4.
Clin Chem Lab Med ; 61(8): 1404-1410, 2023 07 26.
Artigo em Inglês | MEDLINE | ID: mdl-36779362

RESUMO

OBJECTIVES: Clinical laboratory results are required for critical medical decisions, underscoring the importance of quality results. As part of total quality management, external quality assessment (EQA) is a vital component to ensure laboratory accuracy. The goal of this survey was to evaluate the current status of global laboratory quality systems and assess the need for implementation, expansion, or harmonization of EQA programs (EQAP) for Clinical Chemistry and Laboratory Medicine. METHODS: The International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) Task Force on Global Laboratory Quality (TF-GLQ) conducted a survey of IFCC full and affiliate members (n=110) on laboratory quality practice. A total of 41 (37.3%) countries representing all IFCC regions except North America provided responses about EQA availability and practices. RESULTS: All 41 countries perform EQA, 38 reported that their laboratories had EQA policies and procedures, and 39 further act/evaluate unacceptable EQA results. 39 countries indicated they have international and/or national EQAP and 30 use alternative performance assessments. EQA frequency varied among countries. Generally, an EQAP provided the EQA materials (40/41) with four countries indicating that they did not have an EQAP in their country. CONCLUSIONS: Globally, most laboratories participate in an EQAP and have defined quality procedures for EQA. There remain gaps in EQA material availability and implementation of EQA as a part of a total laboratory quality system. This survey highlights the need for education, training, and harmonization and will guide efforts of the IFCC TF-GLQ in identifying areas for enhancing global laboratory quality practices.


Assuntos
Química Clínica , Laboratórios , Humanos , Inquéritos e Questionários , Gestão da Qualidade Total , Garantia da Qualidade dos Cuidados de Saúde
5.
Pract Lab Med ; 22: e00184, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33145388

RESUMO

OBJECTIVES: Point-of-care testing (POCT) is testing performed outside the traditional laboratory, often at the patient bedside. In hospital settings, blood glucose is the most common POCT. Staff performing POCT are not usually laboratory trained; they are clinical staff with a primary focus on treating patients. Clinical staff find POCT quality assurance (QA) practices burdensome and are often non-compliant. In hospitals within EORLA (Eastern Ontario Regional Laboratories Association), all critically high POCT glucose results must be repeated prior to acting, according to policy. Compliance with this policy is audited regularly. DESIGN: and methods: All POCT glucose tests performed in participating sites between January and June 2018 and June and December 2019 were audited for compliance with the critical repeat policy. The discordant repeat rate was also determined for each audit period. Between January and May 2019, there were interventions aimed at improving compliance with the repeat policy. RESULTS: Compliance with the critical repeat policy increased from 30 to 57% in 2019 compared to 2018, following nursing education and implementation of notifications on the glucose meters themselves. The rate of discordant repeat results (>20% different from initial) also improved at most sites in 2019 compared to 2018. Nurses cited insufficient cleaning of patient hands prior to initial testing as the primary reason for discordant repeats. CONCLUSIONS: Operator compliance with POCT QA policies is an ongoing challenge requiring continual audit, feedback and education. A strong POCT multi-disciplinary committee with supports from senior and clinical leadership in an organization are key to improving compliance.

6.
Clin Biochem ; 86: 1-7, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33031819

RESUMO

Clinical laboratories across the world are working to validate and perform testing for SARS-CoV-2 antibodies. Herein, we present interim consensus guidance for Canadian clinical laboratories testing and reporting SARS-CoV-2 serology, with emphasis on the capabilities and limitations of these tests and recommendations for interpretative comments in an effort to achieve harmonized laboratory practices. The consensus document provides a broad overview of topics including sample type and contamination risk; kinetics of antibody response to COVID-19 and the impact on serology testing; clinical utility of SARS-CoV-2 serology testing; clinical performance of commercial laboratory-based assays commonly deployed in North America; recommendations for interim reporting; utility of SARS-CoV-2 antibody testing for pediatric patients; and utility of point-of-care testing. The information is based on the current literature and is subject to change as additional information becomes available.


Assuntos
Teste Sorológico para COVID-19 , COVID-19 , Química Farmacêutica , Pandemias , SARS-CoV-2 , Sociedades Médicas , COVID-19/sangue , COVID-19/epidemiologia , Canadá , Consenso , Humanos
7.
J Cell Sci ; 133(4)2020 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-31974115

RESUMO

Assembly of signaling molecules into micrometer-sized clusters is driven by multivalent protein-protein interactions, such as those found within the nephrin-Nck (Nck1 or Nck2) complex. Phosphorylation on multiple tyrosine residues within the tail of the nephrin transmembrane receptor induces recruitment of the cytoplasmic adaptor protein Nck, which binds via its triple SH3 domains to various effectors, leading to actin assembly. The physiological consequences of nephrin clustering are not well understood. Here, we demonstrate that nephrin phosphorylation regulates the formation of membrane clusters in podocytes. We also reveal a connection between clustering and endocytosis, which appears to be driven by threshold levels of nephrin tyrosine phosphorylation and Nck SH3 domain signaling. Finally, we expose an in vivo correlation between transient changes in nephrin tyrosine phosphorylation, nephrin localization and integrity of the glomerular filtration barrier during podocyte injury. Altogether, our results suggest that nephrin phosphorylation determines the composition of effector proteins within clusters to dynamically regulate nephrin turnover and podocyte health.


Assuntos
Podócitos , Tirosina , Análise por Conglomerados , Endocitose , Proteínas de Membrana , Proteínas Oncogênicas/metabolismo , Fosforilação , Podócitos/metabolismo , Tirosina/metabolismo
8.
Clin Chem Lab Med ; 56(11): 1945-1953, 2018 10 25.
Artigo em Inglês | MEDLINE | ID: mdl-29768245

RESUMO

BACKGROUND: Mucin 13 (MUC13) is a cell surface glycoprotein aberrantly expressed in a variety of epithelial carcinomas. Thus far, the role of MUC13 in various diseases remains elusive. To the best of our knowledge, this is the first study to examine the potential of MUC13 as a serum biomarker in a variety of carcinomas and other conditions. METHODS: We developed a recombinant MUC13 protein, mouse monoclonal antibodies and enzyme immunoassay (ELISA) for MUC13. We used this assay to measure MUC13 levels in the supernatants of cancer cell lines and a large cohort of serum samples from healthy and diseased individuals. RESULTS: MUC13 is secreted from cancer cell lines, with highest levels found in ovarian cancer cell lines. MUC13 levels in human sera were significantly increased in patients with renal failure and 20%-30% of patients with ovarian, liver, lung and other cancers. MUC13 was also elevated in 70% of patients with active cutaneous melanoma, but not uveal melanoma. Furthermore, we identified significant MUC13 elevations in the serum of patients with vasculitis (ANCA-positive) autoantibodies, but not in those with inflammatory bowel disease. CONCLUSIONS: Serum MUC13 is frequently elevated not only in a variety of malignant cases but also in some benign pathologies, thus appearing to be a non-specific disease biomarker. Nonetheless, serum MUC13 is clearly highly elevated in some carcinoma patients, and its relationship with tumor progression in this context warrant further research. Future studies that examine the correlation between serum MUC13 levels to stage of cancer could elucidate prognostic potential.


Assuntos
Biomarcadores Tumorais/análise , Carcinoma/diagnóstico , Ensaio de Imunoadsorção Enzimática/métodos , Mucinas/análise , Doenças Autoimunes/diagnóstico , Doenças Autoimunes/metabolismo , Biomarcadores Tumorais/sangue , Carcinoma/metabolismo , Linhagem Celular Tumoral , Feminino , Humanos , Masculino , Melanoma/diagnóstico , Melanoma/metabolismo , Mucinas/sangue , Neoplasias Ovarianas/diagnóstico , Neoplasias Ovarianas/metabolismo , Neoplasias Cutâneas/diagnóstico , Neoplasias Cutâneas/metabolismo , Melanoma Maligno Cutâneo
9.
Clin Biochem ; 51: 90-96, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28512013

RESUMO

OBJECTIVES: To evaluate the Siemens N-latex kappa free light chain (κFLC) and lambda FLC (λFLC) assays on the BNII nephelometer and assess agreement with The Binding Site Freelite FLC assays on the SPAPlus. DESIGN AND METHODS: Over 180 patient serum samples from routine analysis of κFLC and λFLC measured by the Freelite assay were collected for the study and measured with the N-latex κFLC and λFLC assays to assess precision, linearity, method comparison and dilutional effects. RESULTS: Complex precision showed coefficients of variation of 4.8-7.2% for the κFLC assay and 3.6-6.0% for the λFLC assay. Linearity assessment showed both assays were linear (κFLC, y=1.00x-0.09 and λFLC, y=1.050x-1.252). Qualitative method comparison showed 87.9% (116/132) agreement and Cohen's kappa of 80.4% between the κFLC assays and 72.6% (98/135) agreement and Cohen's kappa of 55.4% for the λFLC assays. Quantitative method comparison for κFLC<150mg/L was y=0.92x+2.21, R=0.661 and for λFLC<150mg/L was y=7.90x-137.96, R=0.526. Dilutional effects including antigen excess and non-linearity were also examined. CONCLUSIONS: The N-latex assay showed good precision and linearity with reasonable agreement to the Freelite assay. However, the assays should not be used interchangeably to monitor patients.


Assuntos
Cadeias kappa de Imunoglobulina/sangue , Cadeias lambda de Imunoglobulina/sangue , Sítios de Ligação , Humanos , Técnicas de Diluição do Indicador , Látex , Paraproteinemias/sangue , Reprodutibilidade dos Testes
10.
Clin Biochem ; 51: 10-20, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29061378

RESUMO

Protein electrophoresis is commonly used as an aid in the diagnosis of monoclonal gammopathies and is performed in many laboratories in Canada and throughout the world. However, unlike many other diagnostic tests, there is limited guidance for standardization and neither guidance nor specific recommendations for clinical reporting of serum (SPE) or urine (UPE) protein electrophoresis and immunotyping available in the literature. Therefore, a Canadian effort was undertaken to recommend standards that cover all aspects of clinical reporting with an ultimate goal towards reporting standardization. The Canadian Society of Clinical Chemists (CSCC) Monoclonal Gammopathy Interest Group (MGIG), which is composed of CSCC members with an interest in protein electrophoresis, has formed a Monoclonal Gammopathy Working Group (MGWG) to take initial steps towards standardization of SPE, UPE and immunotyping. Candidate standardization recommendations were developed, discussed and voted upon by the MGWG. Candidate recommendations that achieved 90% agreement are presented as consensus recommendations. Recommendations that did not achieve 90% consensus remain candidate recommendations and are presented with accompanying MGWG discussion. Eleven consensus recommendations along with candidate recommendations for nomenclature, protein fraction reporting, test utilization, interference handling and interpretive reporting options are presented.


Assuntos
Eletroforese das Proteínas Sanguíneas/métodos , Guias como Assunto , Paraproteinemias/sangue , Sociedades Médicas , Canadá , Humanos
12.
F1000Res ; 6: 1832, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29225777

RESUMO

Background:  Therapeutic drug monitoring of immunosuppressant drugs are used to monitor drug efficacy and toxicity and to prevent organ transplant rejection. This study evaluates the analytical performance of semi-automated electrochemiluminescence immunoassays (ECLIA) for cyclosporine (CSA), tacrolimus (TAC) and sirolimus (SRL) on the Roche cobas e 411 analyzer at a major transplant hospital to assess method suitability and limitations. Methods: Residual whole blood samples from patients undergoing immunosuppressant therapy were used for evaluation. Imprecision, linearity, functional sensitivity, method comparisons and lot-to-lot comparisons were assessed. Results: Total imprecision ranged from 3.3 to 7.1% for CSA, 3.9 to 9.4% for TAC, and 4.6 to 8.2% for SRL. Linearity was verified from 30.0 to 960.9 µg/L for CSA, from 1.1 to 27.1 µg/L for TAC, and from 0.5 to 32.3 µg/L for SRL. The functional sensitivity met the manufacturer's claims and was determined to be <6.5 µg/L for CSA, 1.1 µg/L for TAC, and <0.1 µg/L for SRL (CV≤20%). Deming regression analysis of method comparisons with the ARCHITECT immunoassay yielded slopes of 0.917 (95%CI: 0.885-0.949) and r of 0.985 for CSA, 0.938 (95%CI: 0.895-0.981) and r of 0.974 for TAC, and 0.842 (0.810-1.110) and r of 0.982 for SRL. Deming regression analysis of comparisons with the LC-MS/MS method yielded slopes of 1.331 (95%CI: 1.167-1.496) and r of 0.969 for CSA, 0.924 (95%CI: 0.843-1.005) and r of 0.984 for TAC, and 0.971 (95%CI: 0.913-1.030) and r of 0.993 for SRL. Conclusions: The cobas e 411 ECLIA for CSA, TAC, and SRL have acceptable precision, linearity, and functional sensitivity. The method comparisons correlated well with the ARCHITECT immunoassay and LC-MS/MS and is fit for therapeutic drug monitoring.

13.
Clin Biochem ; 50(18): 1168-1174, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28746862

RESUMO

BACKGROUND: CUB and zona pellucida-like domain-containing protein 1 (CUZD1) was identified as a pancreas-specific protein and was proposed as a candidate biomarker for pancreatic related disorders. CUZD1 protein levels in tissues and biological fluids have not been extensively examined. The purpose of the present study was to generate specific antibodies targeting CUZD1 to assess CUZD1 expression within tissues and biological fluids. METHODS: Mouse monoclonal antibodies against CUZD1 were generated and used to perform immunohistochemical analyses and to develop a sensitive and specific enzyme-linked immunosorbent assay (ELISA). CUZD1 protein expression was assessed in various human tissue extracts and biological fluids and in gel filtration chromatography-derived fractions of pancreatic tissue extract, pancreatic juice and recombinant protein. RESULTS: Immunohistochemical staining of CUZD1 in pancreatic tissue showed that the protein is localized to the acinar cells and the lumen of the acini. Western blot analysis detected the protein in pancreatic tissue extract and pancreatic juice. The newly developed ELISA measured CUZD1 in high levels in pancreas and in much lower but detectable levels in several other tissues. In the biological fluids tested, CUZD1 expression was detected exclusively in pancreatic juice. The analysis of gel filtration chromatography-derived fractions of pancreatic tissue extract, pancreatic juice and recombinant CUZD1 suggested that the protein exists in high molecular weight protein complexes. CONCLUSION: This study describes the development of tools targeting CUZD1 protein, its tissue expression pattern and levels in several biological fluids. These new tools will facilitate future investigations aiming to delineate the role of CUZD1 in physiology and pathobiology.


Assuntos
Células Acinares/metabolismo , Anticorpos Monoclonais Murinos/química , Proteínas de Membrana/metabolismo , Suco Pancreático/metabolismo , Células Acinares/imunologia , Animais , Anticorpos Monoclonais Murinos/imunologia , Feminino , Fluorimunoensaio/métodos , Regulação da Expressão Gênica/imunologia , Humanos , Imuno-Histoquímica/métodos , Masculino , Proteínas de Membrana/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Suco Pancreático/imunologia
15.
Clin Chem Lab Med ; 55(10): 1574-1581, 2017 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-28343172

RESUMO

BACKGROUND: Pancreatic autoantibodies (PABs) are detected in patients with inflammatory bowel disease (IBD). Their prevalence is higher in Crohn's disease (CrD) than in ulcerative colitis (UC). Glycoprotein 2 (GP2) and, more recently, CUB and zona pellucida-like domain-containing protein 1 (CUZD1) have been identified as target autoantigens of PAB. The clinical utility of CUZD1 autoantibodies has only recently been assessed by indirect immunofluorescence (IIF) assays. In this study, we developed and validated novel immunoassays for the detection of CUZD1 autoantibodies. METHODS: Recombinant CUZD1 protein was utilized as a solid-phase antigen for the development of two immunoassays for the detection of IgG and IgA CUZD1 autoantibodies. Serum samples from 100 patients with CrD, 100 patients with UC, 129 patients assessed for various autoimmune diseases (vADs) and 50 control individuals were analyzed. RESULTS: Two immunofluorometric assays for the detection of IgG and IgA CUZD1-specific antibodies were developed. CUZD1 autoantibodies were detected in 12.5% (25/200) IBD patients, including 16% of patients with CrD and in 9% of patients with UC (CrD vs. UC, p<0.05), compared with 3.1% (4/129) patients suspected of having vADs (CrD vs. ADs, p<0.05; UC vs. ADs, p=0.08). CUZD1 autoantibody positivity was not found to be related to disease location, age of disease onset or disease phenotype. CONCLUSIONS: This is the first study to describe novel IgA and IgG CUZD1 autoantibody enzyme-linked immunosorbent assay. These immunoassays agree well with standard IIF techniques and can be utilized in multicenter studies to investigate the diagnostic and clinical utility of CUZD1 autoantibodies.


Assuntos
Autoanticorpos/sangue , Técnica Indireta de Fluorescência para Anticorpo , Doenças Inflamatórias Intestinais/diagnóstico , Proteínas de Membrana/imunologia , Autoanticorpos/imunologia , Colite Ulcerativa/diagnóstico , Doença de Crohn/diagnóstico , Ensaio de Imunoadsorção Enzimática , Humanos , Imunoglobulina A/sangue , Imunoglobulina G/sangue , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/isolamento & purificação
16.
BMC Med ; 14: 73, 2016 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-27151159

RESUMO

These are exciting times for cancer immunotherapy. After many years of disappointing results, the tide has finally changed and immunotherapy has become a clinically validated treatment for many cancers. Immunotherapeutic strategies include cancer vaccines, oncolytic viruses, adoptive transfer of ex vivo activated T and natural killer cells, and administration of antibodies or recombinant proteins that either costimulate cells or block the so-called immune checkpoint pathways. The recent success of several immunotherapeutic regimes, such as monoclonal antibody blocking of cytotoxic T lymphocyte-associated protein 4 (CTLA-4) and programmed cell death protein 1 (PD1), has boosted the development of this treatment modality, with the consequence that new therapeutic targets and schemes which combine various immunological agents are now being described at a breathtaking pace. In this review, we outline some of the main strategies in cancer immunotherapy (cancer vaccines, adoptive cellular immunotherapy, immune checkpoint blockade, and oncolytic viruses) and discuss the progress in the synergistic design of immune-targeting combination therapies.


Assuntos
Anticorpos Monoclonais/uso terapêutico , Antígeno CTLA-4/antagonistas & inibidores , Vacinas Anticâncer/uso terapêutico , Imunoterapia , Neoplasias/tratamento farmacológico , Biomarcadores Tumorais , Terapia Combinada , Humanos , Imunoterapia/métodos , Neoplasias/imunologia
17.
Clin Biochem ; 49(9): 723-725, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27112381

RESUMO

BACKGROUND: Testing for 25-hydroxyvitamin D (25(OH)D) has increased dramatically over the past decade and several automated immunoassays exist to measure serum 25(OH)D. Here we assess the performance of the recently released automated Bio-Rad BioPlex® 2200 25-OH vitamin D immunoassay, claimed to equally detect 25(OH)D2 and 25(OH)D3, and compare its results against a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method and the well-established DiaSorin LIAISON® 25-OH vitamin D total immunoassay. METHODS: Imprecision was determined using third party controls over 20days. Linearity over the claimed measuring range was assessed using admixtures of a high and a low patient pool. Correlation between the BioPlex and LC-MS/MS (n=137) or the LIAISON (n=56) was assessed using patient samples with varying amounts of 25(OH)D3 and/or 25(OH)D2. RESULTS: The total imprecision was 9.4%, 6.9% and 4.5% at concentrations of 39.4nmol/L, 70.6nmol/L and 242.8nmol/L, respectively. The assay was linear from 33.1-375.0nmol/L with a R(2) of 0.993. Method comparison revealed a strong correlation between the BioPlex assay and LC-MS/MS for samples containing 25(OH)D2 alone (n=5; R(2)=0.999), 25(OH)D3 alone (n=119; R(2)=0.935) and both (n=13; R(2)=0.919). In samples tested by all three methods (n=56), the correlation between the BioPlex and the LIAISON (R(2)=0.853) was poorer than that of the BioPlex and LC-MS/MS (R(2)=0.942). CONCLUSION: The BioPlex assay is suitable for the measurement of total serum 25(OH)D. The strong correlation between the BioPlex assay and LC-MS/MS in detecting 25(OH)D2 and 25(OH)D3 provides evidence that the BioPlex assay is capable of the equivalent detection of both forms.


Assuntos
25-Hidroxivitamina D 2/sangue , Biomarcadores/sangue , Calcifediol/sangue , Cromatografia Líquida/métodos , Imunoensaio/métodos , Polímeros/química , Espectrometria de Massas em Tandem/métodos , Humanos , Reprodutibilidade dos Testes
19.
PLoS One ; 10(10): e0139049, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26431551

RESUMO

The validation of candidate biomarkers often is hampered by the lack of a reliable means of assessing and comparing performance. We present here a reference set of serum and plasma samples to facilitate the validation of biomarkers for resectable pancreatic cancer. The reference set includes a large cohort of stage I-II pancreatic cancer patients, recruited from 5 different institutions, and relevant control groups. We characterized the performance of the current best serological biomarker for pancreatic cancer, CA 19-9, using plasma samples from the reference set to provide a benchmark for future biomarker studies and to further our knowledge of CA 19-9 in early-stage pancreatic cancer and the control groups. CA 19-9 distinguished pancreatic cancers from the healthy and chronic pancreatitis groups with an average sensitivity and specificity of 70-74%, similar to previous studies using all stages of pancreatic cancer. Chronic pancreatitis patients did not show CA 19-9 elevations, but patients with benign biliary obstruction had elevations nearly as high as the cancer patients. We gained additional information about the biomarker by comparing two distinct assays. The two CA 9-9 assays agreed well in overall performance but diverged in measurements of individual samples, potentially due to subtle differences in antibody specificity as revealed by glycan array analysis. Thus, the reference set promises be a valuable resource for biomarker validation and comparison, and the CA 19-9 data presented here will be useful for benchmarking and for exploring relationships to CA 19-9.


Assuntos
Antígeno CA-19-9/sangue , Neoplasias Pancreáticas/sangue , Idoso , Idoso de 80 Anos ou mais , Biomarcadores Tumorais/sangue , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pancreatite Crônica/sangue , Sensibilidade e Especificidade
20.
Clin Cancer Res ; 20(22): 5787-95, 2014 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-25239611

RESUMO

PURPOSE: Pancreatic ductal adenocarcinoma (PDAC) is a significant cause of cancer mortality. Carbohydrate antigen 19.9 (CA19.9), the only tumor marker available to detect and monitor PDAC, is not sufficiently sensitive and specific to consistently differentiate early cancer from benign disease. In this study, we aimed to validate recently discovered serum protein biomarkers for the early detection of PDAC and ultimately develop a biomarker panel that could discriminate PDAC from other benign disease better than the existing marker CA19.9. PATIENTS AND METHODS: We performed a retrospective blinded evaluation of 400 serum samples collected from individuals recruited on a consecutive basis. The sample population consisted of 250 individuals with PDAC at various stages, 130 individuals with benign conditions and 20 healthy individuals. The serum levels of each biomarker were determined by ELISAs or automated immunoassay. RESULTS: By randomly splitting matched samples into a training (n = 186) and validation (n = 214) set, we were able to develop and validate a biomarker panel consisting of CA19.9, CA125, and LAMC2 that significantly improved the performance of CA19.9 alone. Improved discrimination was observed in the validation set between all PDAC and benign conditions (AUCCA19.9 = 0.80 vs. AUCCA19.9+CA125+LAMC2 = 0.87; P < 0.005) as well as between early-stage PDAC and benign conditions (AUCCA19.9 = 0.69 vs. AUCCA19.9+CA125+LAMC2 = 0.76; P < 0.05) and between early-stage PDAC and chronic pancreatitis (CP; AUCCA19.9 = 0.59 vs. AUCCA19.9+CA125+LAMC2 = 0.74; P < 0.05). CONCLUSIONS: The data demonstrate that a serum protein biomarker panel consisting of CA125, CA19.9, and LAMC2 is able to significantly improve upon the performance of CA19.9 alone in detecting PDAC.


Assuntos
Biomarcadores Tumorais , Antígeno CA-19-9/metabolismo , Neoplasias Pancreáticas/diagnóstico , Neoplasias Pancreáticas/metabolismo , Adulto , Idoso , Antígeno Ca-125/sangue , Antígeno CA-19-9/sangue , Estudos de Casos e Controles , Feminino , Humanos , Laminina/sangue , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Neoplasias Pancreáticas/patologia , Curva ROC , Reprodutibilidade dos Testes , Fatores de Risco , Neoplasias Pancreáticas
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