scholarly journals Analytical and Clinical Comparison of Two Fully Automated Immunoassay Systems for the Diagnosis of Celiac Disease

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Gabriella Lakos ◽  
Gary L. Norman ◽  
Michael Mahler ◽  
Peter Martis ◽  
Chelsea Bentow ◽  
...  
Keyword(s):  
Celiac Disease ◽  
Clinical Performance ◽  
Iga Deficiency ◽  
Good Qualitative Agreement ◽  
Specific Antibodies ◽  
Automated Assay ◽  
Upper Limit ◽  
Automated Immunoassay ◽  
Positive Results ◽  
Inova Diagnostics

Objective.Here we compared analytical and clinical performance characteristics of two novel automated assay systems for the detection of celiac disease (CD) specific antibodies: QUANTA Flash (INOVA Diagnostics, Inc.) and EliA (Thermo Scientific).Methods.A total of 74 biopsy-proven CD patients (2 with IgA deficiency) and 138 controls were tested by both methods.Results.Sensitivities of QUANTA Flash assays ranged from 35.1% to 90.5% and specificities from 96.4% to 99.3%, while sensitivities for EliA assays ranged from 37.8% to 90.5% (equivocal considered positive) and specificities from 97.1% to 100.0%. Good qualitative agreement was found between all assays. Thirty-four (50.0%) of the 68 QUANTA Flash h-tTG IgA positive results were higher than 10 times the upper limit of normal (ULN). In contrast, only 22.8% of the EliA tTG IgA positive samples were >10x ULN. Seventy-three (98.6%) biopsy-proven CD patients were correctly identified with the QUANTA Flash h-tTG IgA+DGP IgG combination, while 64 (86.5%) and 72 (97.3%) (depending on equivocal range) were identified with the same combination of EliA assays.Conclusion.The QUANTA Flash CD assays have outstanding clinical performance. Of particular clinical significance, in light of proposals to decrease the absolute necessity of biopsy, was the demonstration that 50% of the QUANTA Flash h-tTG IgA results were >10x ULN.

scholarly journals Celiac disease: Understandings in diagnostic, nutritional, and medicinal aspects

2021 ◽  
Vol 35 ◽  
pp. 205873842110087
Author(s):  
Taoufik Ben Houmich ◽  
Brahim Admou
Keyword(s):  
Celiac Disease ◽  
Villous Atrophy ◽  
Current Trend ◽  
Diagnostic Delay ◽  
General Medicine ◽  
Iga Deficiency ◽  
Health Concern ◽  
Intestinal Biopsy ◽  
Antibody Testing ◽  
Main Challenge

Celiac disease (CD) is characterized by clinical polymorphism, with classic, asymptomatic or oligosymptomatic, and extra-intestinal forms, which may lead to diagnostic delay and exposure to serious complications. CD is a multidisciplinary health concern involving general medicine, pediatric, and adult gastroenterology, among other disciplines. Immunology and pathology laboratories have a fundamental role in diagnosing and monitoring CD. The diagnosis consists of serological testing based on IgA anti-transglutaminase (TG2) antibodies combined with IgA quantification to rule out IgA deficiency, a potential misleading factor of CD diagnosis. Positive TG2 serology should be corroborated by anti-endomysium antibody testing before considering an intestinal biopsy. Owing to multiple differential diagnoses, celiac disease cannot be confirmed based on serological positivity alone, nor on isolated villous atrophy. In children with classical signs or even when asymptomatic, with high levels of CD-linked markers and positive HLA DQ2 and/or DQ8 molecules, the current trend is to confirm the diagnosis on basis of the non-systematic use of the biopsy, which remains obligatory in adults. The main challenge in managing CD is the implementation and compliance with a gluten-free diet (GFD). This explains the key role of the dietitian and the active participation of patients and their families throughout the disease-management process. The presence of the gluten in several forms of medicine requires the sensitization of physicians when prescribing, and particularly when dispensing gluten-containing formulations by pharmacists. This underlines the importance of the contribution of the pharmacist in the care of patients with CD within the framework of close collaboration with physicians and nutritionists.

scholarly journals EXPRESS: Clinical performance of the Elecsys® Anti-SARS-CoV-2 combined in an algorithm with two specific anti-IgG immunoassays for the evaluation of the serological response of patients with COVID-19 in a population with a high prevalence of infection

2021 ◽  
pp. 000456322110380
Author(s):  
Xavier Gabaldó-Barrios ◽  
Simona Iftimie ◽  
Anna Hernández-Aguilera ◽  
Isabel Pujol ◽  
Frederic Ballester ◽  
...  
Keyword(s):  
Immune Response ◽  
Polymerase Chain Reaction ◽  
Predictive Value ◽  
Clinical Performance ◽  
Polymerase Chain Reaction Test ◽  
Serological Response ◽  
Chain Reaction ◽  
Automated Assay ◽  
High Prevalence ◽  
Polymerase Chain

Background: Anti-SARS-CoV-2 antibodies have been used in the study of the immune response in infected patients. However, differences in sensitivity and specificity have been reported, depending on the method of analysis. The aim of the present study was to evaluate the diagnostic accuracy of an algorithm in which a high-throughput automated assay for total antibodies was used for screening and two semi-automated IgG-specific methods were used to confirm the results, and also to correlate the analytical results with the clinical data and the time elapsed since infection. Methods: We studied 306 patients, some hospitalized and some outpatients, belonging to a population with a high prevalence of COVID-19. One-hundred and ten patients were classified as SARS-CoV-2 negative and 196 as positive by polymerase chain reaction. Results: The algorithm and automated assay alone had a specificity and a positive predictive value of 100%, although the sensitivity and negative predictive value of the algorithm was higher. Both methods showed a good sensitivity from day 11 of the onset of symptoms in asymptomatic and symptomatic patients. The absorbance of the total antibodies was significantly higher in severely symptomatic than in asymptomatic or mildly symptomatic patients, which suggests the antibody level was higher. We found 15 patients that did not present seroconversion at 12 days from the onset of symptoms or the first polymerase chain reaction test. Conclusion: This study highlights the proper functioning of algorithms in the diagnosis of the immune response to COVID-19, which can help to define testing strategies against this disease.

scholarly journals Evaluation of the INOVA Diagnostics Enzyme-Linked Immunosorbent Assay Kits for Measuring Serum Immunoglobulin G (IgG) and IgA to Deamidated Gliadin Peptides

2006 ◽  
Vol 13 (1) ◽  
pp. 150-151 ◽  
Author(s):  
Harry E. Prince
Keyword(s):  
Celiac Disease ◽  
Immunosorbent Assay ◽  
Immunoglobulin G ◽  
Immunoglobulin A ◽  
Serum Immunoglobulin ◽  
Enzyme Linked Immunosorbent Assay ◽  
Gliadin Antibodies ◽  
Gliadin Peptides ◽  
Disease Specific ◽  
Inova Diagnostics

ABSTRACT New assays for antibodies to deamidated gliadin peptides (DGP) expressing celiac disease-specific epitopes were evaluated using 154 sera previously tested for endomysial immunoglobulin A (IgA) (EMA), transglutaminase IgA (TGA), and conventional gliadin antibodies. DGP antibody results showed 97% concordance with EMA and TGA results. Of 56 sera negative for EMA and TGA but positive for conventional gliadin antibodies, 54 (96%) were negative for DGP antibodies.

Three Years of Experience With Random Urinary Homovanillic and Vanillylmandelic Acid Levels in the Diagnosis of Neuroblastoma

PEDIATRICS ◽  
1987 ◽  
Vol 79 (2) ◽  
pp. 203-205
Author(s):  
Mendel Tuchman ◽  
Margaret L. R. Ramnaraine ◽  
William G. Woods ◽  
William Krivit
Keyword(s):  
False Positive ◽  
Homovanillic Acid ◽  
False Negative ◽  
False Negative Rate ◽  
Urine Samples ◽  
Vanillylmandelic Acid ◽  
Test Results ◽  
Upper Limit ◽  
Positive Results ◽  
Rule Out

During the last 3 years, random urine samples from 408 patients were tested for elevated homovanillic acid (HVA) and vanillylmandelic acid (VMA) levels to rule out the diagnosis of neuroblastoma. Thirty-seven of these patients had elevated HVA and/or VMA levels, and neuroblastoma was subsequently diagnosed. In three additional patients with negative test results (normal HVA and VMA levels), tumors were subsequently diagnosed (false-negative rate of 7.5%). Ten percent of the patients with neuroblastoma had normal HVA and 27.5% had normal VMA levels at the time of diagnosis. Only one patient (2.5%) with neuroblastoma had elevated VMA levels in the presence of normal HVA levels. More than 60% of the patients with neuroblastoma had urinary HVA and/or VMA levels higher than twice the upper limit of normal. No false-positive results were encountered. Age and stage distributions of the patients are shown, and the significance of the results is discussed.

scholarly journals The Prevalence of Celiac Disease-Specific Auto-Antibodies in Type 1 Diabetes in a Moroccan Population

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Ider Oujamaa ◽  
Majda Sebbani ◽  
Lahcen Elmoumou ◽  
Aïcha Bourrahouate ◽  
Rabiy El Qadiry ◽  
...  
Keyword(s):  
Celiac Disease ◽  
Tissue Transglutaminase ◽  
Iga Deficiency ◽  
Cross Sectional Study ◽  
Biological Data ◽  
Cross Sectional ◽  
Systematic Screening ◽  
Lower Height ◽  
Hla Dq2

Objective. We aimed to determine the prevalence of specific auto-antibodies to celiac disease (CD) in Moroccan type 1 diabetic (T1D) patients and compare the clinical and biological characteristics of seropositive and seronegative cases. Patients and Methods. A cross-sectional study was carried out on 276 T1D patients including 109 adults and 167 pediatric cases. The screening for CD was performed by an Elisa IgA anti-tissue transglutaminase antibody (tTGA) testing, combined with IgA quantification by nephelometry. Positive-IgA-tTGA cases were secondly tested for anti-endomysial antibodies (EMA) using an immunofluorescence technique, and the IgA deficiency cases were screened for IgG-tTGA. Patients with low positive tTGA titers underwent HLA-DQ2/DQ8 typing. Sociodemographic and clinical data of the patients were collected using a hetero-administered questionnaire. The comparison of clinical and biological data between seropositive and seronegative diabetics was done using independent T, Mann–Whitney U, chi-squared, and Fisher tests, which were considered significant if p value <0.05. Results. The prevalence of CD-specific auto-antibodies was estimated to be 9.1% (IC = 95%), with 25 positive cases in tTGA and EMA testing. Eight cases displayed low titers of IgA-tTGA, among which 4 were positive for HLA-DQ2, 1 for HLA-DQ8, and 1 for both DQ2 and DQ8. The other 2 cases had a biopsy-proven CD. Compared to seronegative patients, seropositive cases had a higher percentage of associated autoimmune disorders (16% vs. 2.4%, p=0.008), with a significant lower height Z-scores (median: −0.90 (−3.93 to 0.95) vs. −0.51 (−4.54 to 2.18), p=0.029) and a higher HbA1c level (median: 11.30% (7.31 to 16.00) vs. 9.30% (4.40 to17.31), p=0.022). Conclusion. The current study gave evidence of a high prevalence of CD specific auto-antibodies in T1D population. The co-existence of these two conditions was associated with a poor glycemic control, a lower height, and other autoimmune diseases. These findings may suggest the necessity of a systematic screening of CD in T1D patients.

scholarly journals Defining the smallest analyte concentration an immunoassay can measure

1996 ◽  
Vol 42 (6) ◽  
pp. 893-903 ◽  
Author(s):  
E N Brown ◽  
T J McDermott ◽  
K J Bloch ◽  
A D McCollom
Keyword(s):  
Prostate Cancer ◽  
Quality Control ◽  
Diagnostic Tests ◽  
Specific Antigen ◽  
Bayes Theorem ◽  
Analyte Concentration ◽  
Low Concentrations ◽  
Detectable Concentration ◽  
Automated Immunoassay ◽  
Positive Results

Abstract An immunoassay's minimal detectable concentration (MDC), the smallest analyte concentration the assay can reliably measure, is one of its most important properties. Bayes' theorem is used to unify the five current mathematical MDC definitions. The unified definition has significant implications for defining positive results for screening and diagnostic tests, setting criteria for immunoassay quality control and optimal design, reliably measuring biological substances at low concentrations, and, in general, measuring small analyte concentrations with calibrated analytic methods. As an illustration, we apply the unified definition to the microparticle capture enzyme immunoassay for prostate-specific antigen (PSA) developed for the Abbott IMx automated immunoassay system. The MDC of this assay as estimated by our unifying approach is shown to be 4.1-7.1 times greater than currently reported. As a consequence, the ability of the assay to measure reliably small concentrations of PSA to detect early recurrences of prostate cancer is probably overstated.

scholarly journals 1088. Ultrasensitive Detection of C. difficile Toxins in Stool Using Single Molecule Counting Technology: A Multicenter Study for Evaluation of Clinical Performance

2018 ◽  
Vol 5 (suppl_1) ◽  
pp. S325-S326 ◽  
Author(s):  
Stephen Young ◽  
Ray Mills ◽  
Christen Griego-Fullbright ◽  
Aaron Wagner ◽  
Emily Herding ◽  
...  
Keyword(s):  
Single Molecule ◽  
Multicenter Study ◽  
Clinical Performance ◽  
Turnaround Time ◽  
Neutralization Assay ◽  
Single Step ◽  
Reporting Structure ◽  
One Step ◽  
Automated Immunoassay ◽  
Higher Sensitivity

Abstract Background Commercially available tests for Clostridium difficile infection (CDI) make test selection by the laboratory difficult due to the following unsatisfactory characteristics: long turnaround time, poor sensitivity, and/or poor specificity. The Singulex Clarity® C. diff toxins A/B assay (in development) is a rapid and automated immunoassay for the detection of C. difficile toxins A and B in stool, with analytical limits of detection for toxins A and B at 2.0 and 0.7 pg/mL, respectively. In this multicenter study, the clinical performance of the Singulex Clarity C. diff toxins A/B assay was compared with standalone PCR, a multistep algorithm with enzyme immunoassay (EIA) and PCR, and cell cytotoxicity neutralization assay (CCNA). Methods Fresh samples from 267 subjects with suspected CDI were tested at two sites (Minneapolis Medical Research Foundation and TriCore Reference Laboratories) with the Singulex Clarity assay, PCR (Xpert®C. difficile), and EIA (C. Diff Quik Chek Complete®) for GDH and toxin testing. The performance of the assays and multistep algorithms were evaluated against CCNA (Microbiology Specialists, Inc.). Results The overall CDI prevalence was 15.7%. The Singulex Clarity C. diff toxins A/B assay had 90.5% sensitivity and 96.0% specificity, with a 98.2% negative predictive value when compared with CCNA, and the Clarity assay’s AuROC was 0.9534. PCR had 90.5% sensitivity and 91.1% specificity. Compared with CCNA, the toxin EIA had 47.6% sensitivity and 100% specificity. Testing with a multistep algorithm using EIA with discordant results reflexed to PCR resulted in 85.7% sensitivity and 94.7% specificity. Conclusion The ultrasensitive Singulex Clarity C. diff toxins A/B assay is equivalent to the sensitivity of PCR while providing higher specificity. Compared with a multistep algorithm, the Clarity assay provides higher sensitivity and specificity while providing faster time-to-result in a simpler-to-understand, one-step reporting structure, allowing for a standalone, single-step solution for detection of C. difficile toxins in patients with suspected CDI. Disclosures E. Friedland, Singulex, Inc.: Employee, Salary. A. Bartolome, Singulex, Inc.: Employee, Salary. A. Almazan, Singulex, Inc.: Employee, Salary. S. Tam, Singulex, Inc.: Employee, Salary. S. Biscocho, Singulex, Inc.: Employee, Salary. S. Abusali, Singulex, Inc.: Employee, Salary. J. Sandlund, Singulex, Inc.: Employee, Salary. J. Estis, Singulex, Inc.: Employee, Salary. J. Bishop, Singulex, Inc.: Employee, Salary.

Chromogranin-A Levels Measured with Automated Immunoassay

2015 ◽  
Vol 30 (1) ◽  
pp. 132-135 ◽  
Author(s):  
Damien Gruson ◽  
Thibault Lepoutre ◽  
Françoise Smits
Keyword(s):  
Cardiovascular Diseases ◽  
Risk Stratification ◽  
Immunosorbent Assay ◽  
Reference Values ◽  
Chromogranin A ◽  
Turnaround Time ◽  
Enzyme Linked Immunosorbent Assay ◽  
Neuroendocrine Neoplasms ◽  
Automated Assay ◽  
Automated Immunoassay

Measurement of chromogranin-A (CgA) levels is relevant for the diagnosis of neuroendocrine neoplasms. The use of CgA testing for risk stratification of cardiovascular diseases is also increasing. The objective of our study was to determine the performances and reference values of a novel automated assay for CgA testing. The new method was compared with an enzyme-linked immunosorbent assay. Our results showed that the performances of the automated assay were satisfactory and that the agreement between the two methods was excellent. The automation of CgA testing also reduced the turnaround time of analysis and, therefore, might contribute to a faster delivery of the results to physicians.

scholarly journals Is There a Role of Using a Rapid Finger Prick Antibody Test in Screening for Celiac Disease in Children?

2019 ◽  
Vol 2019 ◽  
pp. 1-5 ◽  
Author(s):  
Kristina Baraba Dekanić ◽  
Ivona Butorac Ahel ◽  
Lucija Ružman ◽  
Jasmina Dolinšek ◽  
Jernej Dolinšek ◽  
...  
Keyword(s):  
Celiac Disease ◽  
Point Of Care ◽  
Tissue Transglutaminase ◽  
Rapid Test ◽  
Antibody Test ◽  
First Grade ◽  
Iga Deficiency ◽  
Iga Antibodies ◽  
Point Of Care Tests

Introduction. Celiac disease (CD) is an autoimmune disease triggered by gluten in genetically predisposed individuals. Despite the increasing prevalence of CD, many patients remain undiagnosed. Standard serology tests are expensive and invasive, so several point-of-care tests (POC) for CD have been developed. We aimed to determine the prevalence of CD in first-grade pupils in Primorje-Gorski Kotar County, Croatia, using a POC test. Methods. A Biocard celiac test that detects IgA antibodies to tissue transglutaminase in whole blood was used to screen for celiac disease in healthy first-grade children born in 2011 and 2012 who consumed gluten without restrictions. Results. 1478 children were tested, and none of them were tested positive with a rapid test. In 10 children (0,6%), IgA deficiency has been suspected; only 4 of them agreed to be tested further for total IgA, anti-tTG, and anti-DGP antibodies. IgA deficiency was confirmed in 3 patients, and in all 4 children, CD has been excluded. Conclusion. Our results have not confirmed the usefulness of the POC test in screening the general population of first-grade schoolchildren. Further research is needed to establish the true epidemiology of CD in Primorje-Gorski Kotar County and to confirm the value of the rapid test in comparison with standard antibody CD testing.

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