scholarly journals Sensitivity of anti-SARS-CoV-2 serological assays in a high-prevalence setting

2021 ◽  
Author(s):  
Lisa Müller ◽  
Philipp Niklas Ostermann ◽  
Andreas Walker ◽  
Tobias Wienemann ◽  
Alexander Mertens ◽  
...  
Keyword(s):  
Neutralization Test ◽  
Positive Test ◽  
Test Results ◽  
Immunofluorescence Test ◽  
Neutralization Titer ◽  
Serological Tests ◽  
High Prevalence

AbstractEvaluation and power of seroprevalence studies depend on the performed serological assays. The aim of this study was to assess four commercial serological tests from EUROIMMUN, DiaSorin, Abbott, and Roche as well as an in-house immunofluorescence and neutralization test for their capability to identify SARS-CoV-2 seropositive individuals in a high-prevalence setting. Therefore, 42 social and working contacts of a German super-spreader were tested. Consistent with a high-prevalence setting, 26 of 42 were SARS-CoV-2 seropositive by neutralization test (NT), and immunofluorescence test (IFT) confirmed 23 of these 26 positive test results (NT 61.9% and IFT 54.8% seroprevalence). Four commercial assays detected anti-SARS-CoV-2 antibodies in 33.3-40.5% individuals. Besides an overall discrepancy between the NT and the commercial assays regarding their sensitivity, this study revealed that commercial SARS-CoV-2 spike-based assays are better to predict the neutralization titer than nucleoprotein-based assays are.

scholarly journals Comprehensive characterization of COVID-19 patients with repeatedly positive SARS-CoV-2 tests using a large US electronic health record database

2021 ◽  
Author(s):  
Xiao Dong ◽  
Yujia Zhou ◽  
Xiao-ou Shu ◽  
Elmer Bernstam ◽  
Rebecca Stern ◽  
...  
Keyword(s):  
Electronic Health Record ◽  
Clinical Manifestations ◽  
Positive Test ◽  
Health Record ◽  
Test Results ◽  
High Prevalence ◽  
Testing Data ◽  
Surrogate Measure ◽  
Electronic Health

Background: In the absence of genome sequencing, two positive molecular SARS-CoV-2 tests separated by negative tests, prolonged time, and symptom resolution remain the best surrogate measure of possible re-infection. Methods: Using a large electronic health record database, we characterized clinical and testing data for 23 patients with repeatedly positive SARS-CoV-2 PCR test results >60 days apart, separated by >2 consecutive negative test results. Prevalence of chronic medical conditions, symptoms and severe outcomes related to COVID-19 illness were ascertained. Results: Median age was 64.5 years, 40% were Black, and 39% were female. 83% smoked within the prior year, 61% were overweight/obese, 83% had immune compromising conditions, and 96% had >2 comorbidities. Median interval between the two positive tests was 77 days. Among the 19 patients with 60-89 days between positive tests, 17 (89%) exhibited symptoms or clinical manifestations indicative of COVID-19 at the time of the second positive test and 14 (74%) were hospitalized at the second positive test. Of the four patients with >90 days between two positive tests, two had mild or no symptoms at the second positive test and one, an immune compromised patient, had a brief hospitalization at the first diagnosis, followed by ICU admission at the second diagnosis three months later. Conclusions: Our study demonstrated a high prevalence of immune compromise, comorbidities, obesity and smoking among patients with repeatedly positive SARS-CoV-2 tests. Despite limitations, including lack of semi-quantitative estimates of viral load, these data may help prioritize suspected cases of reinfection for investigation and continued surveillance.

scholarly journals Prevalence of celiac disease in dyspeptic patients

2005 ◽  
Vol 42 (3) ◽  
pp. 153-156 ◽  
Author(s):  
Vinícius Machado de Lima ◽  
Lenora Gandolfi ◽  
José Augusto de Araújo Pires ◽  
Riccardo Pratesi
Keyword(s):  
Celiac Disease ◽  
Serological Test ◽  
Villous Atrophy ◽  
Duodenal Biopsy ◽  
Upper Gastrointestinal Endoscopy ◽  
Test Results ◽  
Serological Tests ◽  
Routine Testing ◽  
Endoscopic Findings ◽  
High Prevalence

BACKGROUND: Celiac disease is one of the most common dietary-mediated inflammatory enteropathies that occur in genetically predisposed individuals in response to gluten intolerance. This disorder has become more common than in the past, even if it frequently remains undetected for long periods of time. The screening of patients with dyspepsia, a symptom that can be a manifestation of celiac disease, may allow an early identification of affected individuals. Endoscopy and serological tests may have an important role in the management of these patients. AIMS: Determining the prevalence of celiac disease in dyspeptic patients submitted to routine diagnostic upper gastrointestinal endoscopy. PATIENTS/METHODS: Endoscopic findings, duodenal biopsy histological specimens and serological test results were assessed and compared in 142 patients consecutively admitted with dyspeptic symptoms between October 2001 and October 2003. RESULTS: An endoscopic pattern suggestive of celiac disease was observed in four patients. The IgG-AGA assay was positive in 24 patients. Two of the IgG-AGA positive patients also yielded positive results on the IgA-EMA test and concomitantly disclosed endoscopic pattern and histological features in duodenal biopsy compatible with celiac disease. Abnormal endoscopic findings were notably marked in biopsy proven celiac patients. Therefore, a 1.4% prevalence of celiac disease was observed in this study group. CONCLUSIONS: The high prevalence of celiac among dyspeptic symptomatic individuals indicates that they are a higher risk group for developing celiac disease. Undiagnosed celiac disease may be inferred by endoscopic markers of duodenal villous atrophy. Endoscopic findings, however, may be inadequate to suitably diagnose this disease and consequently the incorporation of diagnostic serologic assays of celiac disease in routine testing for dyspepsia is strongly recommended.

scholarly journals Effectiveness of Ultraviolet-C Room Disinfection on Preventing Healthcare-Associated Clostridioides difficile Infection

2020 ◽  
Vol 41 (S1) ◽  
pp. s33-s33
Author(s):  
Michihiko Goto ◽  
Erin Balkenende ◽  
Gosia Clore ◽  
Rajeshwari Nair ◽  
Loretta Simbartl ◽  
...  
Keyword(s):  
Acute Care ◽  
Acute Care Hospitals ◽  
Incidence Rates ◽  
Positive Test ◽  
Negative Binomial Regression Model ◽  
Test Results ◽  
Clostridioides Difficile ◽  
Ultraviolet C ◽  
Healthcare Associated ◽  
Uv C

Background: Enhanced terminal room cleaning with ultraviolet C (UVC) disinfection has become more commonly used as a strategy to reduce the transmission of important nosocomial pathogens, including Clostridioides difficile, but the real-world effectiveness remains unclear. Objectives: We aimed to assess the association of UVC disinfection during terminal cleaning with the incidence of healthcare-associated C. difficile infection and positive test results for C. difficile within the nationwide Veterans Health Administration (VHA) System. Methods: Using a nationwide survey of VHA system acute-care hospitals, information on UV-C system utilization and date of implementation was obtained. Hospital-level incidence rates of clinically confirmed hospital-onset C. difficile infection (HO-CDI) and positive test results with recent healthcare exposures (both hospital-onset [HO-LabID] and community-onset healthcare-associated [CO-HA-LabID]) at acute-care units between January 2010 and December 2018 were obtained through routine surveillance with bed days of care (BDOC) as the denominator. We analyzed the association of UVC disinfection with incidence rates of HO-CDI, HO-Lab-ID, and CO-HA-LabID using a nonrandomized, stepped-wedge design, using negative binomial regression model with hospital-specific random intercept, the presence or absence of UVC disinfection use for each month, with baseline trend and seasonality as explanatory variables. Results: Among 143 VHA acute-care hospitals, 129 hospitals (90.2%) responded to the survey and were included in the analysis. UVC use was reported from 42 hospitals with various implementation start dates (range, June 2010 through June 2017). We identified 23,021 positive C. difficile test results (HO-Lab ID: 5,014) with 16,213 HO-CDI and 24,083,252 BDOC from the 129 hospitals during the study period. There were declining baseline trends nationwide (mean, −0.6% per month) for HO-CDI. The use of UV-C had no statistically significant association with incidence rates of HO-CDI (incidence rate ratio [IRR], 1.032; 95% CI, 0.963–1.106; P = .65) or incidence rates of healthcare-associated positive C. difficile test results (HO-Lab). Conclusions: In this large quasi-experimental analysis within the VHA System, the enhanced terminal room cleaning with UVC disinfection was not associated with the change in incidence rates of clinically confirmed hospital-onset CDI or positive test results with recent healthcare exposure. Further research is needed to understand reasons for lack of effectiveness, such as understanding barriers to utilization.Funding: NoneDisclosures: None

scholarly journals Rapid point-of-care (POC) testing for Hepatitis C antibodies in a very high prevalence setting: persons injecting drugs in Tallinn, Estonia

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Anneli Uusküla ◽  
Ave Talu ◽  
Jürgen Rannap ◽  
David M. Barnes ◽  
Don Des Jarlais
Keyword(s):  
Hepatitis C ◽  
Point Of Care ◽  
Antibody Test ◽  
Hcv Rna ◽  
Test Results ◽  
Blood Draw ◽  
Persons Who Inject Drugs ◽  
Oral Swab ◽  
High Prevalence ◽  
Hcv Antibody

Abstract Background Between December 2018 and January of 2019, we evaluated the accuracy of the point-of-care Hepatitis C (HCV) antibody test (POC; OraQuick HCV) used at a community-based needle and syringe exchange program serving persons who inject drugs in Tallinn, Estonia. Methods We compared the results of screening for HCV antibodies by OraQuick (oral swab) and enzyme immunoassay (EIA; blood draw) and assessed test results implications in a high prevalence setting. Findings Of the 100 participants, 88 (88%) had reactive POC test results, and 93 were HCV antibody positive on EIA testing. Sensitivity, specificity and negative predictive value (NPV) for the POC assay with EIA as the relevant reference test were as follows: 94.6% (95% CI 90.0–99.2%), 100% and 58.3% (95% CI 30.4–86.2%). Of the 12 testing, HCV-negative with the POC only 7 (58.3%) were true negatives. Conclusions Oral swab rapid testing HCV screening in this nonclinical setting was sensitive and specific but had unacceptably low NPV. In high prevalence settings, POC tests with high sensitivity and that directly measure HCV RNA may be warranted.

scholarly journals Seroprevalence and correlates of SARS-CoV-2 neutralizing antibodies from a population-based study in Bonn, Germany

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
N. Ahmad Aziz ◽  
Victor M. Corman ◽  
Antje K. C. Echterhoff ◽  
Marcel A. Müller ◽  
Anja Richter ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Response Rate ◽  
Neutralization Test ◽  
Population Based ◽  
Immunofluorescence Assay ◽  
Test Results ◽  
Community Based ◽  
Population Based Study ◽  
Temporal Course ◽  
Confirmatory Tests

AbstractTo estimate the seroprevalence and temporal course of SARS-CoV-2 neutralizing antibodies, we embedded a multi-tiered seroprevalence survey within an ongoing community-based cohort study in Bonn, Germany. We first assessed anti-SARS-CoV-2 immunoglobulin G levels with an immunoassay, followed by confirmatory testing of borderline and positive test results with a recombinant spike-based immunofluorescence assay and a plaque reduction neutralization test (PRNT). Those with a borderline or positive immunoassay result were retested after 4 to 5 months. At baseline, 4771 persons participated (88% response rate). Between April 24th and June 30th, 2020, seroprevalence was 0.97% (95% CI: 0.72−1.30) by immunoassay and 0.36% (95% CI: 0.21−0.61) when considering only those with two additional positive confirmatory tests. Importantly, about 20% of PRNT+ individuals lost their neutralizing antibodies within five months. Here, we show that neutralizing antibodies are detectable in only one third of those with a positive immunoassay result, and wane relatively quickly.

DIAGNOSTIC TESTS FOR TOXOPLASMOSIS

PEDIATRICS ◽  
1949 ◽  
Vol 4 (4) ◽  
pp. 490-497
Author(s):  
F. H. ADAMS ◽  
P. KABLER ◽  
M. COONEY ◽  
J. M. ADAMS
Keyword(s):  
Diagnostic Tests ◽  
Complement Fixation ◽  
Neutralization Test ◽  
Correlation Study ◽  
Positive Test ◽  
Prozone Phenomenon

Results of a correlation study of the rabbit neutralization, complement fixation, skin and slide neutralization tests for toxoplasmosis are presented. The agreement between these is fairly striking, except those from the complement test. Reversal of a positive test was found to occur in the sera of six patients, and, in three instances, the prozone phenomenon was revealed. The new slide neutralization test of Sabin and Feldman appears to be the most accurate, the most economical and the quickest test available at present for the diagnosis of toxoplasmosis.

scholarly journals Lectins for the detection of IgM antibodies to T. gondii in the diagnosis of acute toxoplasmosis by immunofluorescence test

1987 ◽  
Vol 29 (6) ◽  
pp. 354-360
Author(s):  
I. T. I. Nojimoto ◽  
S. Hoshino-Shimizu ◽  
T. K. Nagasse-Sugahara ◽  
M. E. Camargo
Keyword(s):  
Relative Efficiency ◽  
Healthy Subjects ◽  
Lens Culinaris ◽  
Test Results ◽  
Immunofluorescence Test ◽  
Igm Antibodies ◽  
Acute Toxoplasmosis

Lectins were labeled with fluorescein and tried as conjugates in the immunofluorescence (IP) test for the detection of IgM antibodies to T. gondii, in the diagnosis of acute toxoplasmosis. This approach was an attempt to find alternative reagents for anti-human IgM fluorescent conjugates (AHIgMFC), which contain quite frequently anaibcdies to toxoplasma, as contaminants, due to natural T. gondii infections among animals used for imunization. Lentil (Lens culinaris) lectin fluorescence conjugates (LcFC) provided most satisfactory results. The evaluation of LcFC carried out in a total of 179 sera from patients with acute and chronic toxoplasmosis, with non-related infections or healthy subjects, gave high values of relative efficiency, co-positivity and co-negativity indices, respectively 0.989, 0.969 and 1.000, in reference to the conventional AHIgMFC. Moreover, three batches of LcFC successively prepared gave reproducible test results. The advantage of LcFC as an alternative reagent for the serodiagnosis of acute toxoplasmosis is supported by practical aspects of its preparation.

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