Improvement and Multicenter Evaluation of the Analytical Performance of an Automated Chemiluminescent Immunoassay for Alpha Fetoprotein

2012 ◽  
Vol 27 (1) ◽  
pp. 39-46 ◽  
Author(s):  
Kaori Morota ◽  
Makoto Komori ◽  
Ryo Fujinami ◽  
Koji Yamada ◽  
Kageaki Kuribayashi ◽  
...  
Keyword(s):  
Medical Center ◽  
Correlation Coefficients ◽  
Alpha Fetoprotein ◽  
Analytical Performance ◽  
Serum Samples ◽  
Johns Hopkins University ◽  
Limit Of Quantitation ◽  
Chemiluminescent Immunoassay ◽  
Regression Slopes ◽  
Medical University

Background A new ARCHITECT® alpha fetoprotein (AFP) assay was developed to improve the linearity at the upper end of the calibration curve and to enhance other performance characteristics. In addition, this reformulation eliminated the possibility of falsely depressed samples at high AFP concentrations. The purpose of this study was to evaluate its analytical performance at multiple sites. Methods The assay configuration, the diluent formulation, and the manufacturing process were redesigned. Analytical performance was evaluated at Abbott Laboratories, Sapporo Medical University, VU University Medical Center, and Johns Hopkins University. Results The limit of quantitation of the assay was 1.00–1.30 ng/mL. Total precision (%CV) across the assay range varied between 1.41 and 3.52. The assay was linear from 1.19 to 2535 ng/mL, and the range of the assay was expanded from 200 ng/mL to 2000 ng/mL. Comparison of this assay with the on-market ARCHITECT, AxSYM, ADVIA Centaur, DxI, AIA-1800, and E 170 systems yielded regression slopes of 0.91–1.08 and correlation coefficients of ≥0.99 for serum samples. No falsely depressed results were observed in 174 serum samples with AFP concentrations of 2018–1,196,856 ng/mL and in a spiked sample containing up to 10 mg/mL of purified AFP. Conclusions The new AFP assay has improved an issue of the on-market ARCHITECT AFP assay and demonstrated excellent assay performance.

Validation of Soluble Fms-Like Tyrosine Kinase-1 (sFlt-1) and Placental Growth Factor (PlGF) Assays on Cobas e602 System

2020 ◽  
Vol 154 (Supplement_1) ◽  
pp. S12-S13
Author(s):  
Nga Yeung Tang ◽  
Sarosh Rana ◽  
Kiang-Teck J Yeo
Keyword(s):  
Growth Factor ◽  
Tyrosine Kinase ◽  
Medical Center ◽  
Placental Growth Factor ◽  
Analytical Performance ◽  
Hypertensive Disorder ◽  
Limit Of Quantitation ◽  
Roche Diagnostics ◽  
Interference Studies ◽  
Plgf Ratio

Abstract Background Preeclampsia is a leading hypertensive disorder in pregnant women. The angiogenic biomarkers, soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF) ratio, have been shown to be associated with diagnosis and prediction of preeclampsia. The objective of this study is to validate the analytical performance of sFlt-1 and PlGF on the Cobas e602 system (Roche Diagnostics Corporation). Method Intra-day and inter-day precisions for both sFlt-1 and PlGF assays were assessed using quality control materials provided from Roche Diagnostics. The accuracies for both assays were assessed by running 60 patient samples, which have been previously analyzed on the Elecsys 411 analyzer (Roche Diagnostics Corporation) at the Beth Israel Deaconess Medical Center. Linearity studies for both assays were performed using patient plasma spiked with recombinant sFlt-1 and PlGF proteins (R&D systems). Hemolysis, icterus, lipemia and biotin interference studies were performed by spiking hemolysate, bilirubin, intralipid or biotin into either pooled patient plasma with detectable levels of sFlt-1 and PlGF or otherwise, patient plasma spiked with recombinant sFlt-1 and PlGF proteins. Results Total precisions for both assays demonstrated CVs of <5.0%. The sFlt-1 and PlGF assays demonstrated analytical measuring ranges of 3060,000 pg/mL and 79,000 pg/mL, respectively (r2 > 0.98). Lower limit of quantitation (10% CV) was 30 pg/mL for sFlt-1 and 7 pg/mL for PlGF, respectively. Interference studies showed sFlt-1 and PlGF were not significantly affected by hemolysis up to H-indices of 500 and 1000 respectively; both assays were not affected by bilirubin up to an I-index of 60, and lipemia up to an L-index of 2800. Biotin at concentrations >30 ng/mL caused significant negative bias for both sFlt-1 and PlGF assays. Comparison studies showed the following: Cobas e602 sFLT-1 = 1.09 [Elecsys 411 sFLT-1] +203 (r2=0.97, Sy/x=1234, n=58); Cobas e602 PlGF = 1.10 [Elecsys 411 PlGF] +47 (r2=0.99, Sy/x=22.1, n=58); Cobas e602 sFLT-1/PlGF ratio = 0.94 [Elecsys 411 sFLT-1/PlGF ratio] +3.5 (r2=0.91, Sy/x=50, n=58). Conclusion sFlt-1 and PlGF measured on Roche Diagnostics Cobas e602 system demonstrated excellent analytical performance and are acceptable for clinical use once approved in the US.

Estimation of unconjugated, conjugated, and "delta" bilirubin fractions in serum by use of two coated thin films.

1984 ◽  
Vol 30 (8) ◽  
pp. 1314-1317 ◽  
Author(s):  
M W Sundberg ◽  
J J Lauff ◽  
J S Weiss ◽  
G M Dappen ◽  
T W Wu ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Linear Regression ◽  
Total Bilirubin ◽  
Correlation Coefficients ◽  
Comparative Methods ◽  
Serum Samples ◽  
Linear Combinations ◽  
Regression Slopes ◽  
Conjugated Bilirubin

Abstract We used two coated thin films to measure the concentrations of unconjugated, conjugated, and total bilirubin as well as bilirubin covalently bound to albumin ("delta" bilirubin) in more than 400 serum samples. We measured the unconjugated and conjugated species by determining their reflection densities at two wavelengths (400 and 460 nm) on a coating designed for the enhanced spectral measurement of bilirubin but which does not register the delta form. Total bilirubin was measured by use of a diazo-based thin film (Clin Chem 29: 37-41, 1983). We estimated the concentration of delta bilirubin by subtracting the sum of unconjugated and conjugated bilirubin from the concentration of total bilirubin. All measurements agree well with those by comparative methods, as shown by linear regression. Slopes ranged from 0.92 to 1.02, correlation coefficients from 0.935 and 0.998. Linear combinations of these values can also be used to compute other results; e.g., the sum of conjugated and delta bilirubin can be considered to be an estimate of "direct"-reacting bilirubin.

Protocols in Heart and Lung Transplantation: An Essential Guide to Preoperative Assessment and Timing to Improve Outcomes

2004 ◽  
Vol 3 (1) ◽  
pp. 20-25
Author(s):  
Victor Tapson ◽  
Robert Frantz ◽  
John Conte
Keyword(s):  
North Carolina ◽  
Pulmonary Hypertension ◽  
Critical Care ◽  
Lung Transplantation ◽  
Medical Center ◽  
Preoperative Assessment ◽  
Assistant Professor ◽  
Associate Professor ◽  
Johns Hopkins University ◽  
Duke University

This discussion was moderated by Victor Tapson, MD, Editor-in-Chief of Advances in Pulmonary Hypertension and Associate Professor, Division of Pulmonary and Critical Care Medicine, Duke University Medical Center, Durham, North Carolina. The participants included Robert Frantz, MD, Assistant Professor of Medicine, Cardiovascular Division, Mayo Clinic, Rochester, Minnesota; and John Conte, MD, Associate Professor of Surgery and Director of Heart and Lung Transplantation, Johns Hopkins University, Baltimore, MD.

scholarly journals Siphon-Controlled Automation on a Lab-on-a-Disc Using Event-Triggered Dissolvable Film Valves

Biosensors ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 73
Author(s):  
Brian D. Henderson ◽  
David J. Kinahan ◽  
Jeanne Rio ◽  
Rohit Mishra ◽  
Damien King ◽  
...  
Keyword(s):  
Risk Factor ◽  
Limit Of Detection ◽  
C Reactive Protein ◽  
Cvd Risk ◽  
Low Resource Settings ◽  
Low Resource ◽  
Reactive Protein ◽  
Limit Of Quantitation ◽  
Chemiluminescent Immunoassay ◽  
Event Triggered

Within microfluidic technologies, the centrifugal microfluidic “Lab-on-a-Disc” (LoaD) platform offers great potential for use at the PoC and in low-resource settings due to its robustness and the ability to port and miniaturize ‘wet bench’ laboratory protocols. We present the combination of ‘event-triggered dissolvable film valves’ with a centrifugo-pneumatic siphon structure to enable control and timing, through changes in disc spin-speed, of the release and incubations of eight samples/reagents/wash buffers. Based on these microfluidic techniques, we integrated and automated a chemiluminescent immunoassay for detection of the CVD risk factor marker C-reactive protein displaying a limit of detection (LOD) of 44.87 ng mL−1 and limit of quantitation (LoQ) of 135.87 ng mL−1.

scholarly journals Long-Term Longitudinal Evaluation of Six Commercial Immunoassays for the Detection of IgM and IgG Antibodies against SARS CoV-2

Viruses ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1244
Author(s):  
Iulia Nedelcu ◽  
Raluca Jipa ◽  
Roxana Vasilescu ◽  
Cristian Băicuș ◽  
Costin-Ioan Popescu ◽  
...  
Keyword(s):  
Clinical Performance ◽  
Sample Selection ◽  
Early Time ◽  
Humoral Response ◽  
High Specificity ◽  
Data Interpretation ◽  
Serum Samples ◽  
Chemiluminescent Immunoassay ◽  
Chemiluminescent Microparticle Immunoassay ◽  
Antibody Levels

The number of serological assays for SARS-CoV-2 has skyrocketed in the past year. Concerns have been raised regarding their performance characteristics, depending on the disease severity and the time of the analysis post-symptom onset (PSO). Thus, independent validations using an unbiased sample selection are required for meaningful serology data interpretation. We aimed to assess the clinical performance of six commercially available assays, the seroconversion, and the dynamics of the humoral response to SARS-CoV-2 infection. The study included 528 serum samples from 156 patients with follow-up visits up to six months PSO and 161 serum samples from healthy people. The IgG/total antibodies positive percentage increased and remained above 95% after six months when chemiluminescent immunoassay (CLIA) IgG antiS1/S2 and electro-chemiluminescent assay (ECLIA) total antiNP were used. At early time points PSO, chemiluminescent microparticle immunoassay (CMIA) IgM antiS achieved the best sensitivity. IgM and IgG appear simultaneously in most circumstances, and when performed in parallel the sensitivity increases. The severe and the moderate clinical forms were significantly associated with higher seropositivity percentage and antibody levels. High specificity was found in all evaluated assays, but the sensitivity was variable depending on the time PSO, severity of disease, detection method and targeted antigen.

A Simple and Rapid Light-Initiated Chemiluminescence Assay for Quantitation of Artemisia-Specific Immunoglobulin E

2021 ◽  
pp. 1-8
Author(s):  
Dandan Liu ◽  
Bei Zhang ◽  
Lina Zhu ◽  
Lisheng Zheng ◽  
Shaoshen Li ◽  
...  
Keyword(s):  
Food Allergen ◽  
Clinical Guideline ◽  
Immunoglobulin E ◽  
Limit Of Detection ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Chemiluminescence Assay ◽  
Limit Of Quantitation ◽  
Specific Immunoglobulin E ◽  
Specific Immunoglobulin

<b><i>Background:</i></b> Light-initiated chemiluminescence assay (LICA) is a homogeneous assay that has been successfully used for the quantitation of food allergen-specific immunoglobulin E (sIgE), but not inhaled allergen-sIgE. Simultaneously, current assays used to detect allergen-sIgE are serum consuming and/or time consuming. Hence, we established a method for the quantitation of <i>Artemisia</i>-sIgE based on LICA and verified its performance according to the clinical guideline documents, laying a foundation for the quantitation of inhaled and food allergen-sIgE in parallel on LICA. <b><i>Methods:</i></b> The assay was established after optimizing the first incubation time and the dilutions of <i>Artemisia</i>-coated chemibeads, biotinylated goat anti-human IgE, and serum. In order to quantitate <i>Artemisia</i>-sIgE, the calibration curve was established with a high positive serum of known concentration. The assay performance was confirmed per the clinical guideline documents. In addition, the correlation between the results of LICA and capture enzyme-linked immunosorbent assay was evaluated. <b><i>Results:</i></b> The developed LICA’s coefficients of variation of repeatability and intermediate precision were 3.20%, 2.14%, and 3.85% and 4.30%, 4.00%, and 4.40%, respectively. The limit of detection was 0.10 kU<sub>A</sub>/L, and the limit of quantitation was 0.11 kU<sub>A</sub>/L. The range of linearity was from 0.27 kU<sub>A</sub>/L to 97.53 kU<sub>A</sub>/L (<i>r</i> = 0.9968). The correlation coefficient (<i>r</i>) for the correlation analysis between results of LICA and capture ELISA was 0.9087. This assay was successfully applied in 64 human serum samples, showing good sensitivity (82.20%) and specificity (100%). <b><i>Conclusion:</i></b> An <i>Artemisia</i>-sIgE quantitation assay based on LICA was successfully established. Its performance satisfied the clinical requirements and could be widely used in clinical laboratories.

scholarly journals TOXIC ELEMENTS CONTENT ANALYSIS OF BLOOD AND MILK OF COWS

2019 ◽  
pp. 92-97
Author(s):  
T. V Zaznobina ◽  
O. V Ivanova
Keyword(s):  
Blood Serum ◽  
Russian Federation ◽  
Toxic Elements ◽  
Blood Clot ◽  
Experimental Studies ◽  
Correlation Coefficients ◽  
Krasnoyarsk Krai ◽  
Economic Policies ◽  
Serum Samples ◽  
Safe Food

Currently, one of the main economic policies of the Russian Federation in the field of food security is production of safe food and consumer protection. The aim of the research was to study the content of such toxic elements as Zn, Cd and Pb in milk and blood of cows. Experimental studies were carried out at stud farms Plemzavod Tayozhny LLC in Suhobuzimsky District and OPH Solyanskoe LLC in Rybinsk District, Krasnoyarsk Krai, Russian Federation. The milksamples were studied by atomic absorption method; the blood serum samples, by mass spectrometry. Blood serum samples were obtained by sedimentation of whole blood and retraction of the blood clot followed by centrifugation. The obtained data were processed by the method of variation statistics with the calculation of statistical indicators. The lowest contents of Zn, Cd and Pb were found in blood serum of the cows of OPH Solyanskoe LLC; it was 0.038, 0.001, and 0.002 mg/l, respectively. The milk samplescollected at Plemzavod Tayozhny LLCcontained less heavy metals than those collected at OPH Solyanskoe LLC: Zn by 2.069 mg/l, Cd by 0.01 mg/l, and Pb by 0.061 mg/l (P>0.999). When calculating the correlation coefficients, weak positive and negative correlationswere established between Zn and Pb content in blood and milk. The detected amounts of toxic elements did not exceed the maximum permissible concentrations, except for Pb content in milk sampled at OPH Solyanskoe LLC, which was higher than the standard content by 0.026 mg/l.

scholarly journals Effects of TPMT, NUDT15, and ITPA Genetic Variants on 6-Mercaptopurine Toxicity for Pediatric Patients With Acute Lymphoblastic Leukemia in Yunnan of China

2021 ◽  
Vol 9 ◽  
Author(s):  
Xiaoyan Mao ◽  
Runxiu Yin ◽  
Gaoyuan Sun ◽  
Yan Zhou ◽  
Chunhui Yang ◽  
...  
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
Yunnan Province ◽  
Medical Center ◽  
Lymphoblastic Leukemia ◽  
Free Survival ◽  
Ethnic Populations ◽  
Significant Difference ◽  
Pediatric All ◽  
Medical University ◽  
Tolerable Dose

Background: 6-Mercaptopurine (6-MP) is the cornerstone of current antileukemia regimen and contributes greatly to improve the survival of pediatric acute lymphoblastic leukemia (ALL) patients. However, 6-MP dose-related toxicities limit its application. TPMT, NUDT15, and ITPA are pharmacogenetic markers predicting 6-MP-related toxicities, but their genetic polymorphisms differ from those of ethnic populations. In Yunnan province, a multiethnic region of China, we had no genetic data to predict 6-MP toxicities. In this study, we evaluated the most common variants involved in 6-MP metabolism—TPMT*3C (rs1142345), NUDT15 c.415C&gt;T (rs116855232), and ITPA c.94C&gt;A (rs1127354) variants—in our cohort of pediatric ALL patients.Methods: A total of 149 pediatric ALL patients in the Affiliated Children's Hospital of Kunming Medical University (Yunnan Children's Medical Center) from 2017 to 2019 were enrolled in this retrospective study. We assessed the TPMT*3C (rs1142345), NUDT15 c.415C&gt;T (rs116855232), and ITPA c.94C&gt;A (rs1127354) frequencies and evaluated association between genotypes and 6-MP toxicities, 6-MP dose, and event-free survival (EFS) in these ALL patients.Results: The allele frequencies of TPMT*3C (rs1142345), NUDT15 c.415C&gt;T (rs116855232), and ITPA c.94C&gt;A (rs1127354) were 1.34%, 14.43%, and 18.79%, respectively. Only NUDT15 c.415C&gt;T (rs116855232) was strongly associated with 6-MP toxicity and 6-MP tolerable dose. NUDT15 c.415C&gt;T was related to leukopenia, p = 0.008, OR = 2.743 (95% CI: 1.305–5.768). The T allele was significantly correlated with 6-MP tolerable dose, dose of NUDT15 c.415C&gt;T wild genotype CC 39.80 ± 1.32 mg/m2, heterozygotes CT 35.20 ± 2.29 mg/m2, and homozygotes TT 18.95 ± 3.95 mg/m2. 6-MP tolerable dose between CC and TT had a significant difference, p = 0.009. Between CC and CT, and CT and TT, they had no significant difference. EFS showed no significant difference among NUDT15 c.415C&gt;T genotypes.Conclusion:NUDT15 c.415C&gt;T (rs116855232) was an optimal predictor for 6-MP toxicity and tolerable dose in pediatric ALL patients from Yunnan province, a multiethnic region in China, and would play an important role in precise therapy for ALL.

Fluoroscopy time is not accurate as a surrogate for radiation exposure

Vascular ◽  
2017 ◽  
Vol 25 (5) ◽  
pp. 466-471 ◽  
Author(s):  
Edvard Skripochnik ◽  
Shang A Loh
Keyword(s):  
Radiation Exposure ◽  
Medical Center ◽  
Pearson Correlation ◽  
Academic Medical Center ◽  
Surrogate Marker ◽  
Correlation Coefficients ◽  
Frame Rate ◽  
Fluoroscopy Time ◽  
Poor Correlation ◽  
Dose Area Product

Objective The Food and Drug Administration and the Vascular Quality Initiative still utilize fluoroscopy time as a surrogate marker for procedural radiation exposure. This study demonstrates that fluoroscopy time does not accurately represent radiation exposure and that dose area product and air kerma are more appropriate measures. Methods Lower extremity endovascular interventions ( N = 145) between 2013 and 2015 performed at an academic medical center on a Siemens Artis-Zee floor mounted c-arm were identified. Data was collected from the summary sheet after every case. Scatter plots with Pearson correlation coefficients were created. A strong correlation was indicated by an r value approaching 1. Results Overall mean AK and DAP was 380.27 mGy and 4919.2 µGym2. There was a poor correlation between fluoroscopy time and total AK or DAP ( r = 0.27 and 0.32). Total DAP was strongly correlated to cine DAP and fluoroscopy DAP ( r = 0.92 vs. 0.84). The number of DSA runs and average frame rate did not affect AK or DAP levels. Mean magnification level was significantly correlated with total AK ( r = 0.53). Conclusions Fluoroscopy time shows minimal correlation with radiation delivered and therefore is a poor surrogate for radiation exposure during fluoroscopy procedures. DAP and AK are more suitable markers to accurately gauge radiation exposure.

Dual-mode fluorescent and colorimetric immunoassay for the ultrasensitive detection of alpha-fetoprotein in serum samples

2018 ◽  
Vol 1038 ◽  
pp. 112-119 ◽  
Author(s):  
Yaofeng Zhou ◽  
Xiaolin Huang ◽  
Sicheng Xiong ◽  
Xiangmin Li ◽  
Shengnan Zhan ◽  
...  
Keyword(s):  
Alpha Fetoprotein ◽  
Ultrasensitive Detection ◽  
Dual Mode ◽  
Serum Samples ◽  
Colorimetric Immunoassay
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