scholarly journals Multiplex Point-of-Care Tests for the Determination of Antibodies after Acellular Pertussis Vaccination

Diagnostics ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 187
Author(s):  
Aapo Knuutila ◽  
Carita Rautanen ◽  
Jussi Mertsola ◽  
Qiushui He
Keyword(s):  
Point Of Care ◽  
Vaccine Antigen ◽  
Igg Antibodies ◽  
Serum Samples ◽  
Test Platform ◽  
New Type ◽  
Point Of Care Tests ◽  
Spatial Multiplex ◽  
Diagnostic Outcome

Most of the current serological diagnosis of pertussis is based on pertussis toxin (PT) IgG antibodies and does not differentiate between vaccination and infection-induced antibodies. PT is included in all of acellular pertussis vaccines available in the world. Multiplex testing of non-vaccine antigen-related antibodies has the potential to improve the diagnostic outcome of these assays. In this study, we developed a quantitatively spatial multiplex lateral flow immunoassay (LFIA) for the detection of IgG antibodies directed against PT, pertactin (PRN), and filamentous hemagglutinin (FHA). The assay was evaluated with serum samples with varying anti-PT, anti-PRN, and anti-FHA IgG levels and the result was compared to those obtained with standardized ELISA. The developed assay showed good specificity with PT and PRN antibodies and semiquantification throughout the antigen combinations. This exploratory study indicates that the multiplex LFIA is specific and sensitive, and a similar test platform with alternative antigens could be suitable for new type of pertussis serology.

Rapid HIV testing using Determine™ HIV 1/2 antibody tests: is there a difference between the visual appearance of true- and false-positive tests?

2012 ◽  
Vol 23 (9) ◽  
pp. 644-646 ◽  
Author(s):  
R Sacks ◽  
A Omodele-Lucien ◽  
N Whitbread ◽  
D Muir ◽  
A Smith
Keyword(s):  
False Positive ◽  
Point Of Care ◽  
Line Strength ◽  
Positive Sample ◽  
True Positive ◽  
Patient Anxiety ◽  
Serum Samples ◽  
Visual Appearance ◽  
Risk Patients ◽  
Point Of Care Tests

HIV point-of-care tests (POCTs) give occasional false positive results, causing unnecessary patient anxiety. We aimed to elicit whether false- and true-positive POCTs differed visually. Seventeen false- and 17 true-positive serum samples were randomized into pairs, comprising one false- and one true-positive sample. Two independent readers identified each POCT as negative or positive and compared line strength between pairs. Six further readers graded line strength, 0-5, from POCT photographs. All true-positive samples were identified positive and 8/17 false-positive samples negative, on repeat testing of stored sera. Eight out of the 9 remaining false-positive tests were described as having weaker pigment uptake than their paired true-positive POCT. Mean grade of line strength was 4.2 in true- and 0.9 in false-positive samples, on photographic evaluation. These results suggest false-positive POCTs may differ visually from true-positive POCTs. If larger studies confirm these findings, we may be able to alleviate anxiety in low risk patients with faintly positive POCTs awaiting their confirmatory laboratory result, where the possibility of a false-positive result could be emphasized.

Prevalence of scrub typhus in a tertiary care centre in Telangana, south India

2020 ◽  
Author(s):  
Ram Mohan Mylavarapu Venkata Naga Lakshmi ◽  
Teja Vijay Dharma ◽  
Sukanya Sudhaharan ◽  
Subbalaxmi Malladi Venkata Surya ◽  
Rajkiran Emmadi ◽  
...  
Keyword(s):  
Scrub Typhus ◽  
Point Of Care ◽  
Tertiary Care ◽  
Delayed Presentation ◽  
Serum Samples ◽  
Tertiary Care Centre ◽  
Doxycycline Treatment ◽  
Clinical Records ◽  
High Index Of Suspicion ◽  
Point Of Care Tests

Background and Objectives: Scrub typhus is re-emerging as an important cause of acute undifferentiated fever in the last decade from various parts of India. Complexity in performing the “gold standard” immunofluorescent assay and the unre- liable nature of Weil Felix test often results in delayed or misdiagnosis in a majority of cases. The present study seeks to integrate the results of rapid diagnostic tests, clinical and laboratory features to aid the diagnosis and management of scrub typhus patients. Materials and Methods: A total of 645 serum samples with suspected scrub typhus sent to the Department of Microbiology were included in the study. Scrub typhus was tested by rapid immunochromatographic test (SD Diagnostics) and IgM ELI- SA (Inbios International, USA). Clinical features, laboratory parameters and final outcome were analysed from the clinical records of positive patients. Results: Scrub typhus was diagnosed in 13.7% of patients and majority of them were observed in the month of August. 58.6% of scrub typhus patients presented with fever of one to two weeks duration. Eschar was documented in 13.7% of patients and 24% of patients gave a history of working outdoors or exposure to vegetation. All the patients responded to Doxycycline treatment and there was no mortality. Conclusion: High index of suspicion for scrub typhus is necessary in febrile patients not responding to conventional anti- biotics especially during outbreak situations. Rapid immunochromatographic tests with excellent specificity and acceptable sensitivity can be used as potential point of care tests for quick diagnosis of scrub typhus especially in delayed presentation.

scholarly journals Sonochemical synthesis of polyoxometalate-stabilized gold nanoparticles for point-of-care determination of acetaminophen levels: preclinical study in an animal model

RSC Advances ◽  
2020 ◽  
Vol 10 (28) ◽  
pp. 16805-16816
Author(s):  
Tahereh Rohani Bastami ◽  
Abolphazl Ghaedi ◽  
Scott G. Mitchell ◽  
Aida Javadian-Saraf ◽  
Mohammad Karimi
Keyword(s):  
Gold Nanoparticles ◽  
Animal Model ◽  
Clinical Diagnosis ◽  
Point Of Care ◽  
Preclinical Study ◽  
Sonochemical Synthesis ◽  
Serum Samples ◽  
Over The Counter ◽  
Pharmaceutical Tablets

The aim of this study is the accurate detection of acetaminophen (AP) for point-of-care (POC) clinical diagnosis. The concentration of acetaminophen was measured in over-the-counter pharmaceutical tablets and in serum samples taken from mice.

scholarly journals Comparison of diagnostic accuracy for eight SARS-CoV-2 serological assays

2021 ◽  
Vol 31 (1) ◽  
pp. 121-133
Author(s):  
Andrea Tešija Kuna ◽  
Marijana Miler ◽  
Mario Štefanović ◽  
Ivan Šamija ◽  
Josipa Periša ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Severe Disease ◽  
Comparison Study ◽  
Igg Antibodies ◽  
Serum Samples ◽  
Serological Tests ◽  
Perfect Agreement ◽  
Significant Difference ◽  
Polymerase Chain

Introduction: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serological tests have been suggested as an additional diagnostic tool in highly suspected cases with a negative molecular test and determination of seroprevalence in population. We compared the diagnostic performance of eight commercial serological assays for IgA, IgM, and IgG antibodies to the SARS-CoV-2 virus. Materials and methods: The comparison study was performed on a total of 76 serum samples: 30 SARS-CoV-2 polymerase chain reaction (PCR)- negative and 46 SARS-CoV-2 PCR-positive patients with asymptomatic to severe disease and symptoms duration from 3-30 days. The study included: three rapid lateral flow immunochromatographic assays (LFIC), two enzyme-linked immunosorbent assays (ELISA), and three chemiluminescence immunoassays (CLIA). Results: Agreement between IgM assays were minimal to moderate (kappa 0.26 to 0.63) and for IgG moderate to excellent (kappa 0.72 to 0.92). Sensitivities improved with > 10 days of symptoms and were: 30% to 89% for IgM; 89% to 100% for IgG; 96% for IgA; 100% for IgA/IgM combination; 96% for total antibodies. Overall specificities were: 90% to 100% for IgM; 85% to 100% for IgG; 90% for IgA; 70% for IgA/IgM combination; 100% for total antibodies. Diagnostic accuracy for IgG ELISA and CIA assays were excellent (AUC ≥ 0.90), without significant difference. IgA showed significantly better diagnostic accuracy than IgM (P < 0.001). Conclusion: There is high variability between IgM assays independently of the assay format, while IgG assays showed moderate to perfect agreement. The appropriate time for testing is crucial for the proper immunity investigation.

scholarly journals Discovery of Specific Antigens That Can Predict Microfilarial Intensity inLoa loaInfection

2017 ◽  
Vol 55 (9) ◽  
pp. 2671-2678 ◽  
Author(s):  
Papa M. Drame ◽  
Sasisekhar Bennuru ◽  
Thomas B. Nutman
Keyword(s):  
Point Of Care ◽  
Bioinformatic Analysis ◽  
Potential Utility ◽  
Circulating Biomarkers ◽  
Loa Loa ◽  
Serum Samples ◽  
Blood Samples ◽  
Antigen Capture ◽  
Specific Antigens

ABSTRACTAntigen-based immunoassays are currently needed for point-of-care quantification ofLoa loamicrofilariae (mf). Coupling transcriptomic approaches with bioinformatic analysis, we have identified 11 specific putative proteins (coding mRNAs) with potential utility as biomarkers of patent (mf+)L. loainfection. We successfully developed antigen capture immunoassays to quantify 2 (LOAG_14221 and LOAG_15846) of these proteins in individual plasma/serum samples. Of the 2 quantifiable circulating biomarkers, LOAG_14221 showed the highest degree of specificity, particularly with a monoclonal antibody-based immunoassay. Moreover, the levels of LOAG_14221 inL. loamf+patients were positively correlated to the mf densities in the corresponding blood samples (r= 0.53 andP= 0.008 for polyclonal assay;r= 0.54 andP= 0.004 for monoclonal assay). Thus, LOAG_14221 is a very promising biomarker that will be exploited in a quantitative point-of-care immunoassay for determination ofL. loamf densities.

scholarly journals Diagnosis of SARS-CoV-2 infection

2020 ◽  
Vol 40 (2) ◽  
pp. 50-54
Author(s):  
Tatjana Vilibić-Čavlek ◽  
Ljubo Barbić ◽  
Vladimir Savić ◽  
Maja Bogdanić ◽  
Ljiljana Antolašić ◽  
...  
Keyword(s):  
Clinical Symptoms ◽  
Neutralization Test ◽  
Point Of Care ◽  
Disease Onset ◽  
Rt Pcr ◽  
Serum Samples ◽  
Detection Rates ◽  
Extent Of Disease ◽  
Negative Detection

The most important use of serology in the COVID-19 diagnostics is for determination of the extent of disease in the population. However, immunoassays could represent an additional diagnostic method, especially in patients with exposure history and clinical symptoms compatible with COVID-19 who failed to be confirmed by RT-PCR. We analyzed the preliminary results of six serology tests for the diagnosis of SARS-CoV-2. Three point-of-care lateral flow chromatographic immunoassays (POC): ACRO, AMP and ENCODE and three enzyme immunoassays (ELISA): DiaPro, Vircell and Euroimmun were used. A total of 15 serum samples from COVID-19 patients and 15 serum samples from asymptomatic persons were tested. Time of sampling for COVID-19 patients was 4 – 10 days (N=4), 11 – 19 days (N=6) and 20 – 34 days (N=5) after disease onset. Initially reactive results were confirmed using a virus neutralization test (VNT). In COVID-19 patients (N=15), IgM/IgA positive detection rates were 9/60.0% (ACRO), 11/73.3% (AMP, ENCODE, Euroimmun), 12/80.0% (DiaPro) and 13/86.6% (Vircell). Overall IgG detection rates were 10//66.6% (AMP, Euroimmun) and 11/73.3% (other tests). According to the sampling time, positive detection rates were as follows: a) days 4 – 10: 1/25.0% and 2/50.0% (IgM/IgA and IgG); b) days 11 –19: 4/66.6%-6/100% (IgM/IgA), 4/66.6% and 5/83.3% (IgG); c) days 20 – 34: 4/80.0% and 5/100% (IgM/IgA), 5/100% (IgG). One asymptomatic participant tested IgM/IgA positive using ACRO, DiaPro and Vircell was confirmed seropositive using a VNT. In a group of asymptomatic persons detected seronegative using a VNT (N=14), IgM/IgA negative detection rates were 12/85.7% (ACRO), 13/92.8% (DiaPro, Vircell) and 14/100% (AMP, ENCODE, Euroimmun). IgG negative detection rates were 13/92.8% (ACRO) and 14/100% (other tests). ELISA tests showed a higher overall IgM/IgA sensitivity compared to POC tests in patients with COVID-19, while the IgG sensitivity was similar in both POC and ELISA.

scholarly journals Study of eosinophil cationic protein serum levels in patients with toxocariasis

2020 ◽  
Vol 2 (3) ◽  
pp. 178-182
Author(s):  
Eleonara Marinova Kaneva ◽  
◽  
Rumen Nenkov Harizanov ◽  
Iskra Georgieva Rainova ◽  
Iskren Tsvetkov Kaftandjiev ◽  
...  
Keyword(s):  
Eosinophil Cationic Protein ◽  
Serum Levels ◽  
Disease Stage ◽  
Confirmatory Test ◽  
Ocular Involvement ◽  
Igg Antibodies ◽  
Serum Samples ◽  
Recent Infection ◽  
Cationic Protein

Introduction: Toxocariasis is a zoonotic helminth infection with difficult diagnosis. Determination of specific IgG antibodies alone does not allow to establish the disease stage and to evaluate the treatment efficacy. Therefore it is necessary to identify additional markers that will assist the diagnosis. The purpose of our study was to identify and monitor eosinophil cationic protein (ECP) levels in patients with toxocariasis confirmed by serology and to compare our data with the literature to determine the relevance of this protein as an indicator for recent infection and the effectiveness of the therapy. Material and methods: ELISA (CUSABIO) commercial kit was used for determination of ECP concentration. Sixty serum samples were studied from individuals previously tested and confirmed for toxocariasis by the presence of specific anti-Toxocara IgG antibodies in ELISA (Toxocara IgG Rbiopharm) and the presence of specific bands in Western blot as confirmatory test (LD BIO). Twenty serum samples from clinically healthy blood donors were used as a control group. Results: The mean concentration of serum ECP in the patients with toxocariasis was significantly higher than in clinically healthy subjects. Seventy-two percent of patients affected by toxicariasis showed increased serum concentration of ECP. However, no statistically significant differences were observed in terms of age (p = 0.451) and sex (p = 0.682) of the patients or clinical form of the disease. ECP levels among patients with visceral toxocariasis were relatively higher (mean 22.99 ng / ml ± 13.16 SD) in comparison to those with ocular involvement (15.60 ng/ml ± 9.92 SD). Correlation between the presence of peripheral eosinophilia and the concentration of serum ECP was not also established. Conclusion: Data from our study give us reason to believe that serum levels of ECP could serve as an additional marker indicating recent infection, especially in patients without marked increase in the blood eosinophils.

scholarly journals Identification and Pilot Evaluation of Salivary Peptides from Anopheles albimanus as Biomarkers for Bite Exposure and Malaria Infection in Colombia

2020 ◽  
Vol 21 (3) ◽  
pp. 691 ◽  
Author(s):  
Berlin Londono-Renteria ◽  
Papa M. Drame ◽  
Jehidys Montiel ◽  
Ana M. Vasquez ◽  
Alberto Tobón-Castaño ◽  
...  
Keyword(s):  
Disease Risk ◽  
Mosquito Species ◽  
Igg Antibodies ◽  
Anopheles Albimanus ◽  
Serum Samples ◽  
Igg Antibody ◽  
Quantitative Immunoassay ◽  
Risk Of Disease ◽  
Antibody Levels

Insect saliva induces significant antibody responses associated with the intensity of exposure to bites and the risk of disease in humans. Several salivary biomarkers have been characterized to determine exposure intensity to Old World Anopheles mosquito species. However, new tools are needed to quantify the intensity of human exposure to Anopheles bites and understand the risk of malaria in low-transmission areas in the Americas. To address this need, we conducted proteomic and bioinformatic analyses of immunogenic candidate proteins present in the saliva of uninfected Anopheles albimanus from two separate colonies—one originating from Central America (STECLA strain) and one originating from South America (Cartagena strain). A ~65 kDa band was identified by IgG antibodies in serum samples from healthy volunteers living in a malaria endemic area in Colombia, and a total of five peptides were designed from the sequences of two immunogenic candidate proteins that were shared by both strains. ELISA-based testing of human IgG antibody levels against the peptides revealed that the transferrin-derived peptides, TRANS-P1, TRANS-P2 and a salivary peroxidase peptide (PEROX-P3) were able to distinguish between malaria-infected and uninfected groups. Interestingly, IgG antibody levels against PEROX-P3 were significantly lower in people that have never experienced malaria, suggesting that it may be a good marker for mosquito bite exposure in naïve populations such as travelers and deployed military personnel. In addition, the strength of the differences in the IgG levels against the peptides varied according to location, suggesting that the peptides may able to detect differences in intensities of bite exposure according to the mosquito population density. Thus, the An. albimanus salivary peptides TRANS-P1, TRANS-P2, and PEROX-P3 are promising biomarkers that could be exploited in a quantitative immunoassay for determination of human-vector contact and calculation of disease risk.

scholarly journals Determination of Specific Anti - Toxocara Antibodies in Patients with Cardiac Disease

2021 ◽  
Vol 9 (3) ◽  
pp. 36
Author(s):  
Eleonora Kaneva ◽  
Rumen Harizanov ◽  
Stefka Krumova ◽  
Petya Genova-Kalu ◽  
Iskra Rainova ◽  
...  
Keyword(s):  
Heart Disease ◽  
Western Blot ◽  
Cardiac Disease ◽  
Igg Antibodies ◽  
Serological Study ◽  
Serum Samples ◽  
Primary Screening ◽  
Inflammatory Heart Disease ◽  
Disease Specific

Aim of this study is to find the seroprevalence of specific anti - Toxocara IgG antibodies among patients with inflammatory heart disease and to evaluate the significance of this parasite as a possible etiological agent of such pathology. We performed a serological study of 41 patients with heart disease (myocarditis, pericarditis and endocarditis) for presence of specific anti-Toxocara IgG antibodies. We used ELISA for primary screening, and Western blot as a confirmatory method. Presence of specific anti-Toxocara IgG antibodies in ELISA was detected in three (7.3%) of the serum samples, and another two (4.9%) were with borderline values. These serum samples were further examined in Western blot and three of them (7.3%) displayed disease-specific bands. We do not in any way claim that in these cases Toxocara infection is the cause of inflammatory heart disease, but the data from the study shows that such a link is possible.

Trial production of γ-type energy filtering TEM

1995 ◽  
Vol 53 ◽  
pp. 604-605
Author(s):  
Y. Taniguchi ◽  
E. Nakazawa ◽  
S. Taya
Keyword(s):  
Magnetic Energy ◽  
Electron Optics ◽  
Electron Microscopic ◽  
Mass Spectrometers ◽  
Ion Optics ◽  
Energy Filtering ◽  
New Information ◽  
New Type ◽  
Fringing Fields

Imaging energy filters can add new information to electron microscopic images with respect to energy-axis, so-called electron spectroscopic imaging (ESI). Recently, many good results have been reported using this imaging technique. ESI also allows high-contrast observation of unstained biological samples, becoming a trend of the field of morphology. We manufactured a new type of energy filter as a trial production. This energy filter consists of two magnets, and we call γ-filter since the trajectory of electrons shows ‘γ’-shape inside the filter. We evaluated the new energyγ-filter TEM with the γ-filter.Figure 1 shows schematic view of the electron optics of the γ-type energy filter. For the determination of the electron-optics of the γ-type energy filter, we used the TRIO (Third Order Ion Optics) program which has been developed for the design of high resolution mass spectrometers. The TRIO takes the extended fringing fields (EFF) into consideration. EFF makes it difficult to design magnetic energy filters with magnetic sector fields.

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