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Steven J Soldin - One of the best experts on this subject based on the ideXlab platform.
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assessment of thyroid function in intensive care unit patients by liquid chromatography tandem mass spectrometry methods
Clinical Biochemistry, 2017Co-Authors: Kerry J Welsh, Brian R Stolze, Trisha R Podsiadlo, Lisa S Kim, Steven J SoldinAbstract:Abstract Objectives Patients with non-thyroidal illness syndrome have many abnormalities in thyroid hormone tests. Such patients have medical comorbidities associated with low serum proteins and are on multiple medications that interfere with thyroid hormone measurement by Immunoassay platforms. It is unknown if these thyroid hormone measurements reflect physiologic conditions or if they are artifacts of testing methodology. Methods Fifty patients were selected from the intensive care unit (ICU) from our institution. Total and free thyroid hormones in plasma were measured by gold standard liquid chromatography-tandem mass spectrometry (LC-MSMS). The results were compared to the Roche Cobas 6000. Patient medical comorbidities and binding protein levels were assessed. Results Concentrations of total 3,5,5′-triidothyronine (TT3) and total thyroxine (TT4) were significantly more likely to be low by LC-MSMS compared to Immunoassay. Free 3,5,5′-triidothyronine (FT3) levels were similar by Immunoassay and LC-MSMS. However, FT4 concentrations were mildly elevated for many patients when measured by ultrafiltration LC-MSMS (19/50, 38%) compared to 1/50 (2%) when measured by Immunoassay ( p = 0.0001). Decreased albumin and thyroxine binding globulin were common and patients were on an average of 11.7 ± 5.0 medications, all factors known to interfere with results found on Immunoassays. Conclusions Marked discrepancies in thyroid hormone measurement were noted between reference LC-MSMS and a common Immunoassay platform. It is hypothesized that T4 binding to low affinity albumin is displaced by several drugs, raising concentrations of FT4 by LC-MSMS compared to Immunoassay, and that the Immunoassay values are falsely decreased due to low binding proteins in our patient population.
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the expanding role of tandem mass spectrometry in optimizing diagnosis and treatment of thyroid disease
Advances in Clinical Chemistry, 2013Co-Authors: Hendrick E Van Deventer, Steven J SoldinAbstract:This review discusses the state-of-the-art measurement of free and total thyroid hormones in clinical laboratories. We highlight some of the limitations of currently used Immunoassays and critically discuss physical separation methods for the measurement of free thyroid hormone. Physical separation methods, such as equilibrium dialysis or ultrafiltration, followed by tandem mass spectrometry for the measurement of free thyroid hormones offer many advantages, which we feel, can deepen our understanding of thyroid hormone metabolism and improve patient diagnosis and care. Problems with direct analogue Immunoassay methods for FT4/FT3 as well as Immunoassay methods for total T3 at low T3 concentrations and during pregnancy are highlighted. Improved diagnosis and patient management can be achieved utilizing tandem mass spectrometry for these measurements.
Iva R Kennedy - One of the best experts on this subject based on the ideXlab platform.
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rapid determination of fumonisin b1 in food samples by enzyme linked immunosorbent assay and colloidal gold Immunoassay
Journal of Agricultural and Food Chemistry, 2006Co-Authors: Shuo Wang, Ying Qua, Nanju Lee, Iva R KennedyAbstract:A rapid enzyme-linked immunosorbent assay (ELISA) test (microwell plate) and a membrane-based colloidal gold Immunoassay in flow-through and lateral-flow formats for the rapid detection of fumonisin B1 (FB1) were developed. The rapid microwell assay can be completed within 20 min with the detection limit of 0.5 ± 0.2 μg/L. Membrane-based colloidal gold Immunoassays had a visual detection limit of 1.0 μg/L for FB1 with the detection time of <10 min. Matrix interference was eliminated by 15-fold dilutions of methanol extracts with buffer. These Immunoassays can be used as quantitative or qualitative tools for the rapid detection of FB1 residues in 10−20 min on-site. Keywords: Fumonisin B1; rapid microwell plate ELISA; colloidal gold Immunoassay; on-site screening
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rapid determination of fumonisin b1 in food samples by enzyme linked immunosorbent assay and colloidal gold Immunoassay
Journal of Agricultural and Food Chemistry, 2006Co-Authors: Shuo Wang, Nanju Lee, Ying Quan, Iva R KennedyAbstract:A rapid enzyme-linked immunosorbent assay (ELISA) test (microwell plate) and a membrane-based colloidal gold Immunoassay in flow-through and lateral-flow formats for the rapid detection of fumonisin B1 (FB1) were developed. The rapid microwell assay can be completed within 20 min with the detection limit of 0.5 ( 0.2 Ig/L. Membrane-based colloidal gold Immunoassays had a visual detection limit of 1.0 Ig/L for FB1 with the detection time of <10 min. Matrix interference was eliminated by 15-fold dilutions of methanol extracts with buffer. These Immunoassays can be used as quantitative or qualitative tools for the rapid detection of FB1 residues in 10-20 min on-site.
Zhimin Tim Cao - One of the best experts on this subject based on the ideXlab platform.
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measurement of unconjugated estriol in serum by liquid chromatography tandem mass spectrometry and assessment of the accuracy of chemiluminescent Immunoassays
Clinical Chemistry, 2014Co-Authors: Xianzhang Huang, David C Spink, Erasmus Schneider, Helen Ling, Alex J Rai, Thomas G Rosano, Baorong Chen, Zhimin Tim CaoAbstract:BACKGROUND: Unconjugated estriol (uE3) is routinely analyzed in clinical laboratories as risk assessment for Down syndrome. Immunoassays of various types are the most commonly used methods. The accuracies of RIAs and ELISAs for uE3 have been questioned, and to date there have been no independent studies investigating the accuracy of the relatively new chemiluminescent Immunoassays. We developed and validated a liquid chromatography–tandem mass spectrometry (LC-MS/MS) method for uE3 measurements in serum. METHODS: Serum samples from patients in the second trimester of pregnancy were used, and uE3 concentrations were measured by LC-MS/MS and the Beckman Coulter Access® 2 and Siemens IMMULITE 2000 automatic chemiluminescent Immunoassay analyzers. RESULTS: The LC-MS/MS method was validated and showed limit of detection 0.05 ng/mL; limit of quantification 0.2 ng/mL; linearity of response to 32 ng/mL; total imprecision of 16.2%, 10.4%, and 8.2% for uE3 at 1.10, 4.18, and 8.32 ng/mL, respectively; and analytical recoveries of 95.9%–104.2%. ANOVA of the correlation for LC-MS/MS results vs chemiluminescent Immunoassays results showed R 2 = 0.9678 (Access 2 = 0.9305 LC-MS/MS + 0.2177, S y | x = 0.1786, P < 0.0001), and R 2 = 0.9663 (IMMULITE 2000 = 0.8849 LC-MS/MS − 0.0403, S y | x = 0.1738, P < 0.0001). Bland–Altman plots of uE3 results revealed concentration-dependent Immunoassay biases. Mock risk analysis for Down syndrome showed no apparent difference in the risk assessment outcomes if the adjusted method-specific multiples of the median were used, and the assay imprecision was <10% CV. CONCLUSIONS: Standardization of Immunoassay methods for uE3 analysis is needed to improve the accuracy of the measurements.
David H Wilson - One of the best experts on this subject based on the ideXlab platform.
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the simoa hd 1 analyzer a novel fully automated digital Immunoassay analyzer with single molecule sensitivity and multiplexing
Journal of Laboratory Automation, 2016Co-Authors: David H Wilson, David M Rissin, Todd G Campbell, Raymond E Meyer, Purvish P Patel, David Fournier, T Piech, Matthew W. Fishburn, Carlos Cabrera, Erica FrewAbstract:Disease detection at the molecular level is driving the emerging revolution of early diagnosis and treatment. A challenge facing the field is that protein biomarkers for early diagnosis can be present in very low abundance. The lower limit of detection with conventional Immunoassay technology is the upper femtomolar range (10−13 M). Digital Immunoassay technology has improved detection sensitivity three logs, to the attomolar range (10−16 M). This capability has the potential to open new advances in diagnostics and therapeutics, but such technologies have been relegated to manual procedures that are not well suited for efficient routine use. We describe a new laboratory instrument that provides full automation of single-molecule array (Simoa) technology for digital Immunoassays. The instrument is capable of single-molecule sensitivity and multiplexing with short turnaround times and a throughput of 66 samples/h. Singleplex and multiplexed digital Immunoassays were developed for 16 proteins of interest in ...
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rapid fully automated digital Immunoassay for p24 protein with the sensitivity of nucleic acid amplification for detecting acute hiv infection
Clinical Chemistry, 2015Co-Authors: Carlos Cabrera, Lei Chang, Mars Stone, Michael P. Busch, David H WilsonAbstract:Background: Nucleic acid testing (NAT) has become the standard for high sensitivity in detecting low levels of virus. However, adoption of NAT can be cost prohibitive in low-resource settings where access to extreme sensitivity could be clinically advantageous for early detection of infection. We report development and preliminary validation of a simple, low-cost, fully automated digital p24 antigen Immunoassay with the sensitivity of quantitative NAT viral load (NAT-VL) methods for detection of acute HIV infection. Methods: We developed an investigational 69-min Immunoassay for p24 capsid protein for use on a novel digital analyzer on the basis of single-molecule-array technology. We evaluated the assay for sensitivity by dilution of standardized preparations of p24, cultured HIV, and preseroconversion samples. We characterized analytical performance and concordance with 2 NAT-VL methods and 2 contemporary p24 Ag/Ab combination Immunoassays with dilutions of viral isolates and samples from the earliest stages of HIV infection. Results: Analytical sensitivity was 0.0025 ng/L p24, equivalent to 60 HIV RNA copies/mL. The limit of quantification was 0.0076 ng/L, and imprecision across 10 runs was <10% for samples as low as 0.09 ng/L. Clinical specificity was 95.1%. Sensitivity concordance vs NAT-VL on dilutions of preseroconversion samples and Group M viral isolates was 100%. Conclusions: The digital Immunoassay exhibited >4000-fold greater sensitivity than contemporary Immunoassays for p24 and sensitivity equivalent to that of NAT methods for early detection of HIV. The data indicate that NAT-level sensitivity for acute HIV infection is possible with a simple, low-cost digital Immunoassay.
Shuo Wang - One of the best experts on this subject based on the ideXlab platform.
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rapid determination of fumonisin b1 in food samples by enzyme linked immunosorbent assay and colloidal gold Immunoassay
Journal of Agricultural and Food Chemistry, 2006Co-Authors: Shuo Wang, Ying Qua, Nanju Lee, Iva R KennedyAbstract:A rapid enzyme-linked immunosorbent assay (ELISA) test (microwell plate) and a membrane-based colloidal gold Immunoassay in flow-through and lateral-flow formats for the rapid detection of fumonisin B1 (FB1) were developed. The rapid microwell assay can be completed within 20 min with the detection limit of 0.5 ± 0.2 μg/L. Membrane-based colloidal gold Immunoassays had a visual detection limit of 1.0 μg/L for FB1 with the detection time of <10 min. Matrix interference was eliminated by 15-fold dilutions of methanol extracts with buffer. These Immunoassays can be used as quantitative or qualitative tools for the rapid detection of FB1 residues in 10−20 min on-site. Keywords: Fumonisin B1; rapid microwell plate ELISA; colloidal gold Immunoassay; on-site screening
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rapid determination of fumonisin b1 in food samples by enzyme linked immunosorbent assay and colloidal gold Immunoassay
Journal of Agricultural and Food Chemistry, 2006Co-Authors: Shuo Wang, Nanju Lee, Ying Quan, Iva R KennedyAbstract:A rapid enzyme-linked immunosorbent assay (ELISA) test (microwell plate) and a membrane-based colloidal gold Immunoassay in flow-through and lateral-flow formats for the rapid detection of fumonisin B1 (FB1) were developed. The rapid microwell assay can be completed within 20 min with the detection limit of 0.5 ( 0.2 Ig/L. Membrane-based colloidal gold Immunoassays had a visual detection limit of 1.0 Ig/L for FB1 with the detection time of <10 min. Matrix interference was eliminated by 15-fold dilutions of methanol extracts with buffer. These Immunoassays can be used as quantitative or qualitative tools for the rapid detection of FB1 residues in 10-20 min on-site.
