Detection of Antiphospholipid Antibodies Using a Novel Multiplex Test Method: Correlation with ELISA Methods.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 4102-4102
Author(s):  
Kim A. Janatpour ◽  
Robert C. Gosselin ◽  
John T. Owings ◽  
Ted Wun
Keyword(s):  
Cost Effective ◽  
Elisa Test ◽  
Small Sample ◽  
Test Method ◽  
Antibody Detection ◽  
Antiphospholipid Antibody ◽  
Antiphospholipid Antibody Syndrome ◽  
Test Results ◽  
Clinical Sensitivity ◽  
Positive Results

Abstract -Background: Laboratory criteria for the antiphospholipid antibody syndrome (APS) include detection of the lupus anticoagulant (LA) by coagulation based tests, or detection of either anti-cardiolipin (aCL), or anti-B2-glycoprotein I (aB2GPI) antibodies by enzyme-linked immunoabsorbant assay (ELISA). Multiplex testing enables simultaneous measurement of multiple serum antibodies with small beads coated with target antigens and small sample volumes (5 μL). We compared the concordance of a prototype multiplex method to standard ELISA methods for measuring IgG and IgM antibodies directed against CL or B2GPI. Methods: Samples from patients with suspected APS were tested for IgG and IgM aCL and aB2GPI antibodies using standard ELISA methods (ELISA, Bio-Rad Laboratories, Hercules, CA) and by a prototype multiplex bead set analyzed on the BioPlex 2200 (Bio-Rad Laboratories, Hercules, CA). The multiplex method used beads coated with either CL alone, B2GPI alone, or CL-B2GPI complex. Results were normalized using ratios (obtained result/upper limit of normal). A positive result was defined as a ratio of > 1. For CL, the multiplex test is considered positive if positive results are present using beads with either the CL alone or the CL-B2GPI complex. Results: Table 1. Concordance of ELISA vs Multiplex tests for antiphospholipid antibody detection Multiplex Test Results Concordance (%) ELISA Test Results Positive Negative Positive Negative All Results aCL-IgG Positive (n=52) 30 22 58 - Negative (n=232) 32 200 - 86 82 aCL-IgM Positive (n=42) 32 10 76 - Negative (n=241) 34 207 - 85 84 aβ2GPI-IgG Positive (n=34) 20 14 59 - Negative (n=249) 17 232 - 93 89 aβ2GPI-IgM Positive (n=61) 31 30 51 - Negative (n=219) 22 197 - 90 81 Conclusions: The overall concordance of multiplex results with ELISA results was good (81–89%). Negative multiplex results showed excellent correlation with ELISA (85–93%). Positive multiplex results had variable correlation with ELISA (51–76%). Evaluation of clinically significant positive results and clinical outcome measures is needed to determine clinical sensitivity and specificity of the multiplex test. Further refinement of the multiplex platform may provide an efficient and cost-effective assay for antibodies associated with the antiphospholipid syndrome.

scholarly journals Near-Field Immunity Test Method for Fast Radiated Immunity Test Debugging of Automotive Electronics

Electronics ◽  
2019 ◽  
Vol 8 (7) ◽  
pp. 797 ◽  
Author(s):  
Jawad Yousaf ◽  
Doojin Lee ◽  
JunHee Han ◽  
Hosang Lee ◽  
Muhammad Faisal ◽  
...  
Keyword(s):  
Automotive Industry ◽  
Near Field ◽  
Cost Effective ◽  
Field Testing ◽  
Input Power ◽  
Test Method ◽  
Automotive Electronics ◽  
Test Results ◽  
Electric Power Steering ◽  
Power Steering

This study presents a near-field immunity test (NFIT) method for the fast debugging of radiated susceptibility of industrial devices. The proposed approach is based on the development of an NFIT setup which comprises of developed near-field electric and magnetic field probes and device under test (DUT). The developed small-size and handy near-field testing probes inject the high electric (up to 1000 V/m) and magnetic (up to 2.4 A/m) fields on the DUT in the radar pulse ranges (1.2 to 1.4 GHz and 2.7 to 3.1 GHz) with the lower fed input power (up to 15 W) from the power amplifier in the developed NFIT setup. The proof of concept is validated with the successful near-field immunity debugging of an electric power steering (EPS) device used in the automotive industry with the developed NFIT setup. The radiated susceptibility debugging test results of developed NFIT method and conventional method of ISO 11452-2 test setup turned out to be close to each other for the tested DUT in immunity performance. The proposed procedure has advantages of industry usefulness with fast, handy, and cost-effective radiated immunity debugging of the DUT without the requirement of large antenna, high-power amplifiers, optical DUT connecting harness, and an anechoic chamber as needed in ISO 11452-2 standard setup for the debugging analysis.

scholarly journals Highly Sensitive and Specific SARS-CoV-2 Serological Assay Using a Magnetic Modulation Biosensing System

Biosensors ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 7
Author(s):  
Shira Avivi-Mintz ◽  
Yaniv Lustig ◽  
Victoria Indenbaum ◽  
Eli Schwartz ◽  
Amos Danielli
Keyword(s):  
Viral Infections ◽  
Limit Of Detection ◽  
Turnaround Time ◽  
Elisa Test ◽  
Antibody Detection ◽  
Enzyme Linked Immunosorbent Assay ◽  
Igg Antibodies ◽  
Serological Assay ◽  
Clinical Sensitivity ◽  
Highly Sensitive

Sensitive serological assays are needed to provide valuable information about acute and past viral infections. For example, detection of anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) IgG antibodies could serve as the basis for an “immunity passport” that would enable individuals to travel internationally. Here, utilizing a novel Magnetic Modulation Biosensing (MMB) system and the receptor-binding domain of the SARS-CoV-2 spike protein, we demonstrate a highly sensitive and specific anti-SARS-CoV-2 IgG serological assay. Using anti-SARS-CoV-2 IgG antibodies, RT-qPCR SARS-CoV-2-positive and healthy patients’ samples, and vaccinees’ samples, we compare the MMB-based SARS-CoV-2 IgG assay’s analytical and clinical sensitivities to those of the enzyme-linked immunosorbent assay (ELISA). Compared with ELISA, the MMB-based assay has an ~6-fold lower limit of detection (129 ng/L vs. 817 ng/L), and it detects an increase in the IgG concentration much earlier after vaccination. Using 85 RT-qPCR SARS-CoV-2-positive samples and 79 -negative samples, the MMB-based assay demonstrated similar clinical specificity (98% vs. 99%) and sensitivity (93% vs. 92%) to the ELISA test, but with a much faster turnaround time (45 min vs. 245 min). The high analytical and clinical sensitivity, short turnaround time, and simplicity of the MMB-based assay makes it a preferred method for antibody detection.

scholarly journals Sensitive detection of multiple islet autoantibodies in type 1 diabetes using small sample volumes by agglutination-PCR

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0242049
Author(s):  
Felipe de Jesus Cortez ◽  
David Gebhart ◽  
Peter V. Robinson ◽  
David Seftel ◽  
Narges Pourmandi ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
Sensitivity And Specificity ◽  
High Sensitivity ◽  
Small Sample ◽  
Insulin Autoantibodies ◽  
Islet Autoantibodies ◽  
Antibody Detection ◽  
Clinical Sensitivity ◽  
Analysis Platform

Islet autoantibodies are predominantly measured by radioassay to facilitate risk assessment and diagnosis of type 1 diabetes. However, the reliance on radioactive components, large sample volumes and limited throughput renders radioassay testing costly and challenging. We developed a multiplex analysis platform based on antibody detection by agglutination-PCR (ADAP) for the sample-sparing measurement of GAD, IA-2 and insulin autoantibodies/antibodies in 1 μL serum. The assay was developed and validated in 7 distinct cohorts (n = 858) with the majority of the cohorts blinded prior to analysis. Measurements from the ADAP assay were compared to radioassay to determine correlation, concordance, agreement, clinical sensitivity and specificity. The average overall agreement between ADAP and radioassay was above 91%. The average clinical sensitivity and specificity were 96% and 97%. In the IASP 2018 workshop, ADAP achieved the highest sensitivity of all assays tested at 95% specificity (AS95) rating for GAD and IA-2 autoantibodies and top-tier performance for insulin autoantibodies. Furthermore, ADAP correctly identified 95% high-risk individuals with two or more autoantibodies by radioassay amongst 39 relatives of T1D patients tested. In conclusion, the new ADAP assay can reliably detect the three cardinal islet autoantibodies/antibodies in 1μL serum with high sensitivity. This novel assay may improve pediatric testing compliance and facilitate easier community-wide screening for islet autoantibodies.

scholarly journals Phospholipid Autoantibodies and the Antiphospholipid Antibody Syndrome: Diagnostic Accuracy of 23 Methods Studied by Variation in ROC Curves with Number of Clinical Manifestations

2002 ◽  
Vol 48 (7) ◽  
pp. 1004-1010 ◽  
Author(s):  
Jan-Christian Wasmuth ◽  
Desamparados Oliver y Miñarro ◽  
Angela Homrighausen ◽  
Ludger Leifeld ◽  
Jürgen K Rockstroh ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Clinical Manifestations ◽  
Signs And Symptoms ◽  
Roc Curves ◽  
Antiphospholipid Antibody ◽  
Antiphospholipid Antibody Syndrome ◽  
Test Results ◽  
Glycoprotein I ◽  
Immunoglobulin Isotypes ◽  
The Individual

Abstract Background: We analyzed the diagnostic accuracies for the diagnosis of antiphospholipid syndrome (APS) of 23 antiphospholipid antibody (APL-Ab) assays targeted at different antigen preparations and immunoglobulin isotypes. Methods: In 144 patients with suspected APS, anti-cardiolipin (aCL) and anti-β2-glycoprotein I (aβ2GPI) antibodies were measured with 23 different ELISAs from three manufacturers. Data were analyzed by ROC curves. In the absence of an accepted criterion standard, the endpoint “diagnosis of APS” was varied according to the number (two through five) of signs and symptoms of APS. Results: Although the presence of lupus anticoagulant was associated significantly with APL-Ab in 10 of 23 assays (P = 0.01–10−4) and recurrent arterial or venous occlusions were significantly associated with APL-Ab of IgM isotype in 5 of 6 assays (P = 0.02–10−4), sensitivity for detection of APS did not exceed 67%. With the exception of IgA APL-Ab, the diagnostic accuracy of the assays improved when the diagnosis of APS was based on an increasing number of simultaneous features of APS. For most methods, areas under the ROC curves were >0.8 irrespective of the method’s subclass specificity and antigen preparation (aCL or aβ2GPI), if the clinical diagnosis of APS was based on four or more signs and symptoms of APS. Conclusion: Despite considerable heterogeneity in the individual test results, a single test of IgG or IgM isotype targeted at either aCL or aβ2GPI antibodies has excellent diagnostic accuracy when the criterion for diagnosis requires four or more typical manifestations of APS.

scholarly journals Do Current Antiphospholipid Antibody Syndrome Guidelines Effectively Target at-Risk Obstetric Patients?

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 1208-1208
Author(s):  
Kanika Thapar ◽  
Nimesh Patel ◽  
Bolanle Gbadamosi ◽  
Daniel E Ezekwudo ◽  
Ishmael Jaiyesimi ◽  
...  
Keyword(s):  
At Risk ◽  
Venous Thromboembolism ◽  
Gestational Age ◽  
Fetal Loss ◽  
Antiphospholipid Antibody ◽  
Antiphospholipid Antibody Syndrome ◽  
Recurrent Fetal Loss ◽  
Clinical Criteria ◽  
Significant Difference ◽  
Positive Results

Abstract Introduction: The incidence of spontaneous miscarriages is 1%, and up to 50% of recurrent fetal losses (RFL) have unclear etiology. Antiphospholipid syndrome (APS) has been reported in 5-15% of women with RFL. Current clinical criteria for APS include venous thromboembolism (VTE) and /or fetal loss. In addition to the clinical criteria, laboratory confirmation must be obtained using tests for lupus anticoagulant (LA), anticardiolipin (ACL) and beta-2 glycoprotein I antibodies (β2GPI). These tests are often provided by many laboratories as panels; moreover, given the relatively large number of tests, judicious ordering of these panels is warranted to contain costs and to avoid mislabeling patients who have clinically insignificant positive results. Some existing literature suggests that patients with recurrent fetal loss and ACL antibodies are over-tested and/or over-diagnosed. We aim to determine the frequency and likelihood of positive antiphospholipid antibody (APA) among patients with fetal loss. Materials and Methods: A retrospective search was conducted for APA panels using data from our laboratory information system from Jan 2014 to Jan 2015. Recorded variables included age, ordering physician subspecialty and indication for testing. For patients with fetal loss, the number of losses and gestational age at the time of loss were recorded. Specimens were classified as positive, indeterminate or negative. For positive and indeterminate tests, the results of LA, ACL, and β2GPI antibody tests and titers were noted. Results: Our search identified 430 panels ordered for APA. The median age was 42 (range: 1-92). The three highest ordering physician subspecialties were Ob/Gyn (20.2%), Internal Medicine (17.7%) and Heme/Onc (17.2%). The three most common indications for ordering the APA panel were venous thromboembolism (26.5%), fetal loss (18.4%), and autoimmune disease (15.4%). The largest percentage of positive results came from panels ordered by Heme/Onc 45% (20/44) and for the indication of VTE 40.9% (18/44). Fetal loss (n=74) accounted for 4.5% (2/44) of positive results. Further investigation of the fetal loss cases showed that 82.4 % (61/74) met criteria for appropriate APA testing. There was no statistically significant difference for gestational age < 10 weeks (1 positive, 4 indeterminate, and 30 negative specimens) or > 10 weeks (1 positive, 1 indeterminate, and 37 negatives; p=0.334); ordering physician subspecialty and the APA testing result. Both fetal loss patients that tested positive for APS had increased titers of ACL IgM and β2GPI IgM. Conclusions: Despite being the second most common indication for APA testing, fetal loss only accounted for 4.5% of positive results. Compared to historical data that report an incidence of 5-15% APS in patients with recurrent fetal loss, we found an incidence of only 2.7%. The reason for this discrepancy is not clear. Confounding factors such as inappropriate work-ups or incomplete testing are unlikely as 82.7% of patients meet standard testing criteria and our APA panels included multiple tests for LA, ACL and β2GPI. Larger studies are needed to confirm our findings, as this may call for redefinition of APA testing guidelines to better target at risk obstetric patients. Disclosures No relevant conflicts of interest to declare.

A censored sequential posterior odd test method in testability demonstration test planning

2020 ◽  
Vol 234 (4) ◽  
pp. 579-587 ◽  
Author(s):  
Yong Zhang ◽  
Chao Wang ◽  
Xin Lin ◽  
Guanjun Liu ◽  
Peng Yang ◽  
...  
Keyword(s):  
Sample Size ◽  
Fault Injection ◽  
Classical Method ◽  
Small Sample ◽  
Test Method ◽  
Fault Detection And Isolation ◽  
Test Results ◽  
Case Application ◽  
Increasing Demand ◽  
Average Sample

Testability demonstration tests can effectively verify product capabilities of fault detection and isolation; however, they suffer from insufficient samples, long cycles and high costs due to destructiveness of fault injection tests, which leads to an increasing demand for small sample tests. The sequential posterior odd test can effectively reduce sample sizes, but test results can be random and the sample size may be large. In this article, a censored sequential posterior odd test method is proposed, which can control the incremental risk caused by forced censoring within a contracted range by risk splitting. The development process of the testability demonstration test based on the censored sequential posterior odd test is designed. The number of censored tests and the calculation method of the censored threshold are presented. The case application shows that with the same prior distribution and constraint parameters, the average sample size of the proposed method is smaller than that of the sequential posterior odd test and of the classical method considering risks for both producers and consumers. The presented method can further reduce the risk of misjudgment and the number of test samples, contributing to the reduction of the test cycle and costs.

scholarly journals China NMPA perspective on clinical evaluation of SARS-CoV-2 antibody test reagents in the process of emergency approval

Bioanalysis ◽  
2020 ◽  
Author(s):  
Yunfeng Lv ◽  
Jingyun He ◽  
Rongzhi Liu ◽  
Yu Gao ◽  
Chao Xu ◽  
...  
Keyword(s):  
Early Stage ◽  
Antibody Test ◽  
Standard Test ◽  
Test Method ◽  
Antibody Detection ◽  
Test Results ◽  
Antibody Testing ◽  
National Medical ◽  
Key Points ◽  
Antigen Antibody

Coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The SARS-CoV-2 antibody testing an important supplement to nucleic acid testing. In the process of emergency approval, the Center for Medical Device Evaluation of the China National Medical Products Administration released The Key Points of Technical Review for the Registration of SARS-CoV-2 Antigen/Antibody Detection Reagents. The Clinical Study Requirement section of the Key Point has put forward requirements in terms of reference methods and subject enrolment among others, which can ensure that the test results can meet the clinical needs. This article draws on the experience of the China NMPA in evaluating diagnostic reagents used to supplement the gold standard test method in the early stage of an epidemic of an infectious disease, as well as to serve as reference for clinicians and regulators.

scholarly journals Evaluation of antigen detection and antibody detection tests for Trypanosoma evansi infections of buffaloes in Indonesia

1999 ◽  
Vol 123 (1) ◽  
pp. 149-155 ◽  
Author(s):  
H. C. DAVISON ◽  
M. V. THRUSFIELD ◽  
S. MUHARSINI ◽  
A. HUSEIN ◽  
S. PARTOUTOMO ◽  
...  
Keyword(s):  
Operating Characteristic ◽  
False Negative ◽  
Trypanosoma Evansi ◽  
Antibody Detection ◽  
Test Results ◽  
Likelihood Ratios ◽  
Significant Difference ◽  
Post Test ◽  
Positive Results ◽  
Rule Out

Two Ag-ELISAs, an IgG-specific antibody detection ELISA (IgG ELISA) and a card agglutination test (CATT) for the detection of Trypanasoma evansi infections in buffaloes in Indonesia, were compared. Diagnostic sensitivity estimates were obtained by testing sera from 139 Indonesian buffaloes which had been found to be infected by parasitological tests. Diagnostic specificity was estimated by testing sera from 263 buffaloes living in Australia. Response-operating characteristic curves were constructed, and optimal ELISA cut-off values, which minimized the number of false–negative and false–positive results, were chosen. The IgG ELISA had the highest sensitivity (89%) and the CATT had the highest specificity (100%). There was a significant difference between the sensitivities (71 and 81%), but not between the specificities (75 and 78%), of the two Ag-ELISAs. The four tests were further compared by calculation of post-test probabilities of infection for positive and negative test results using a range of prevalence values, and likelihood ratios. The results suggested that the CATT was the best test to ‘rule-in’ infection (i.e. the highest probability of infection in test-positive animals) and the IgG ELISA was the best test to ‘rule-out’ infection (i.e. the lowest probability of infection in test-negative animals).

Automated Latex Agglutination and ELISA Testing Yield Equivalent D-Dimer Results in Patients with Recent Myocardial Infarction

1999 ◽  
Vol 82 (11) ◽  
pp. 1412-1416 ◽  
Author(s):  
Wojciech Zareba ◽  
John Horan ◽  
Arthur Moss ◽  
Joel Kanouse ◽  
◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Elisa Test ◽  
Mean Value ◽  
Latex Agglutination ◽  
Test Results ◽  
Coronary Death ◽  
Elisa Testing ◽  
Strong Linear Correlation ◽  
Highly Correlated ◽  
D Dimer

SummaryOur previous prospective study of post-infarction patients described a strong and significant association of increased plasma D-dimer concentrations in those who experienced a subsequent coronary death or non-fatal myocardial infarction. In the present study, we compare results on stored plasma obtained two months after the index myocardial infarction from 1,038 patients of this trial, using a simple automated latex agglutination (LA) assay in parallel with the standard ELISA test. Results show a somewhat higher mean value for the LA assay (702 ± 1092 vs. 638 ± 986 ng/ml, p = 0.0002), a strong linear correlation of the two assays (r = 0.86) and 88% agreement for values below 500 ng/ml by the ELISA test. D-dimer concentrations determined by each assay were highly correlated in patients with subsequent coronary artery events (p = 0.93) and quartile values for both the LA and ELISA were equally predictive of such events (p = 0.003 and p = 0.001, respectively). This is the first demonstration that a latex agglutination assay for D-dimer can be used to assess the prognostic risk of recurrent coronary thrombotic disease after myocardial infarction

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