Missed opportunities for the diagnosis of Brucella infection among slaughterhouse workers at the Kumasi Abattoir, Ghana

Brucellosis is a zoonotic disease in humans with its public health importance. Laboratory diagnostic methods targeting brucellosis are not performed in hospital settings across Ghana. Very little is known about the comparative diagnostic abilities of the various tests available presently. The aim of this study therefore was to evaluate and compare diagnostic performances of Rose Bengal Plate Test (RBPT), Enzyme Linked Immunosorbent Assay (ELISA) and Polymerase Chain Reaction (PCR) employed in diagnosing Brucella infection.Two hundred and twenty Abattoir workers were randomly selected in Kumasi, Ghana. Blood samples were collected, serum extracted and tested for the presence of anti-Brucella antibodies and compared among three different techniques, using ELISA, RBPT and PCR.From the 220 participants tested for antibodies against Brucella spp., 3 (1.4%), 4 (1.8%) and 21 (9.6%) were positive for Rose Bengal Plate test, anti-Brucella ELISA IgM and anti-Brucella ELISA IgG respectively. A total of 98 (44.5%) participants tested positive by PCR. The sensitivity, specificity, positive predictive value, negative predictive values and Kappa value for Rose Bengal in comparison with PCR were 66.7%, 55.8%, 2.0%, 100% and 0.013 respectively while that for ELISA IgG in comparison with PCR were 85.7%, 71.3%, 18.4%, 98.5% and 0.212 respectively.PCR yielded the highest sensitivity and specificity among the three diagnostic methods in this study and should be considered for use at strategic reference laboratories to augment existing routine serological tests for brucella performed in laboratories in Ghana.

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Comparison of RPR and ELISA with TPHA for the Diagnosis of Syphilis: Implication for Updating Syphilis Point-of-Care Tests in Ethiopia

Journal of Immunology Research ◽

10.1155/2018/2978419 ◽

2018 ◽

Vol 2018 ◽

pp. 1-7 ◽

Cited By ~ 1

Author(s):

Markos Negash ◽

Tadelo Wondmagegn ◽

Demeke Geremew

Keyword(s):

Transmitted Disease ◽

Treponema Pallidum ◽

Public Health Problem ◽

Elisa Test ◽

Confirmatory Test ◽

Enzyme Linked Immunosorbent Assay ◽

Major Public Health Problem ◽

Predictive Values ◽

Kappa Value ◽

Sensitivity Specificity

Background.Syphilis is a sexually transmitted disease (STD) caused by the spirocheteTreponema pallidum, and it persists to be a major public health problem in Africa, including Ethiopia. Syphilis diagnosis is made by either nontreponemal or treponemal approaches, though in developing countries the diagnosis relies mostly on nonspecific tests due to several reasons. Thus, the objective of this study was to assess the sensitivity, specificity, predictive values, and agreement of rapid plasma reagin (RPR) and enzyme-linked immunosorbent assay (ELISA) withTreponema pallidumhemagglutination assay (TPHA) as a gold standard for the diagnosis of syphilis.Results. The sensitivity, specificity, and positive and negative predictive values of ECOTEST-RPR were 100%, 80.8%, 76.2%, and 100%, respectively. However, the sensitivity, specificity, and positive and negative predictive values of DIALAB-ELISA were 98.4%, 94.9%, 92.3%, and 98.9%, respectively. The agreement between DIALAB-ELISA and Randox-TPHA was excellent (kappa value: 0.96) as compared to ECOTEST-RPR and Randox-TPHA assay (kappa value: 0.88).Conclusion.We found a characteristically variable performance of DIALAB-ELISA test and the currently available traditional ECOTEST-RPR test in the study area. The use of ECOTEST-RPR as a diagnostic test is confronted by its false positivity. Thus, neither the ECOTEST-RPR nor the DIALAB-ELISA test stands on its own to be used either as screening or confirmatory test for syphilis diagnosis. Consequently, thorough studies should be conducted aiming on a change of the current diagnostic scheme in the community.

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Development And Performance Evaluation of A Rapid In-House ELISA for Retrospective Serosurveillance of SARS-CoV-2

10.1101/2020.12.10.20244350 ◽

2020 ◽

Cited By ~ 1

Author(s):

Bijon Kumar Sil ◽

Mumtarin Jannat Oishee ◽

Md. Ahsanul Haq ◽

Nowshin Jahan ◽

Tamanna Ali ◽

...

Keyword(s):

Clinical Signs ◽

Blocking Agent ◽

Diagnostic Methods ◽

Molecular Diagnostic ◽

Rt Pcr ◽

Serological Tests ◽

Predictive Values ◽

Monitoring Tools ◽

Kappa Value ◽

And Performance

Background In the ongoing pandemic situation of COVID-19, serological tests can complement the molecular diagnostic methods, and can be one of the important tools of sero-surveillance and vaccine evaluation. Aim To develop and evaluate a rapid SARS-CoV-2 specific IgG ELISA with increased sensitivity and specificity. Methods In order to develop the ELISA, three panels of samples (n=184) have been used: panel 1 (n=19) and panel 2 (n=60) were collected from RT-PCR positive patients within 14 and after 14 days respectively following the onset of clinical signs of disease whereas panel 3 consisted of negative samples (n=105) collected either from healthy donors during pre-pandemic era, pandemic era or from RT-PCR negative healthy individuals. As a capturing agent full-length SARS-CoV-2 specific recombinant nucleocapsid was immobilized and blocked using blocking agent. In total of 30 samples from the panels have been tested with Elecsys Anti-SARS-CoV-2 for selecting positive and negative controls, as well as comparator assay. The threshold cut-off point, inter-assay and intra assay variations were determined. Results The assay time was set at a total of 30 minutes with the sensitivity of 84% (95% confidence interval, CI, 60.4%, 96.6%) and 98% (95% CI, 91.1%, 100.0%), for panel 1 and 2 respectively, with overall 94.9% sensitivity (95% CI 87.5%, 98.6%). Moreover, the clinical specificity is 97.1% (95% CI, 91.9%, 99.4%) with no cross-reaction with dengue sample. The overall positive and negative predictive values are 96.2% (95% CI 89.2%, 99.2%) and 96.2% (95% CI, 90.6% 99.0%) respectively. In-house ELISA demonstrated 100% positive and negative percent agreement with ROCHE (Elecsys; Anti-SARS-CoV-2), with a Cohens kappa value of 1.00 (very strong agreement), while comparing 13 positive and 17 negative confirmed cases. Conclusion The assay is rapid and can be applied as one of the early and retrospective sero-monitoring tools in all over the affected areas.

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Development and performance evaluation of a rapid in-house ELISA for retrospective serosurveillance of SARS-CoV-2

PLoS ONE ◽

10.1371/journal.pone.0246346 ◽

2021 ◽

Vol 16 (2) ◽

pp. e0246346

Author(s):

Bijon Kumar Sil ◽

Nowshin Jahan ◽

Md. Ahsanul Haq ◽

Mumtarin Jannat Oishee ◽

Tamanna Ali ◽

...

Keyword(s):

Clinical Symptoms ◽

Diagnostic Methods ◽

Molecular Diagnostic ◽

Serological Tests ◽

Predictive Values ◽

Monitoring Tools ◽

Healthy Donors ◽

Kappa Value ◽

And Performance ◽

Selection Of

Background In the ongoing pandemic situation of COVID-19, serological tests can complement the molecular diagnostic methods, and can be one of the important tools of sero-surveillance and vaccine evaluation. Aim To develop and evaluate a rapid SARS-CoV-2 specific ELISA for detection of anti-SARS-CoV2 IgG from patients’ biological samples. Methods In order to develop this ELISA, three panels of samples (n = 184) have been used: panel 1 (n = 19) and panel 2 (n = 60) were collected from RT-PCR positive patients within 14 and after 14 days of onset of clinical symptoms, respectively; whereas panel 3 consisted of negative samples (n = 105) collected either from healthy donors or pre-pandemic dengue patients. As a capturing agent full-length SARS-CoV2 specific recombinant nucleocapsid was immobilized. Commercial SARS-CoV2 IgG kit based on chemiluminescent assay was used for the selection of samples and optimization of the assay. The threshold cut-off point, inter-assay and intra-assay variations were determined. Results The incubation/reaction time was set at a total of 30 minutes with the sensitivity of 84% (95% confidence interval, CI, 60.4%, 96.6%) and 98% (95% CI, 91.1%, 100.0%), for panel 1 and 2, respectively; with overall 94.9% sensitivity (95% CI 87.5%, 98.6%). Moreover, the clinical specificity was 97.1% (95% CI, 91.9%, 99.4%) with no cross reaction with dengue samples. The overall positive and negative predictive values are 96.2% (95% CI 89.2%, 99.2%) and 96.2% (95% CI, 90.6% 99.0%), respectively. In-house ELISA demonstrated 100% positive and negative percent agreement with Elecsys Anti-SARS-CoV-2, with Cohen’s kappa value of 1.00 (very strong agreement), while comparing 13 positive and 17 negative confirmed cases. Conclusion The assay is rapid and can be applied as one of the early and retrospective sero-monitoring tools in all over the affected areas.

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COVID-19 Seroprevalence among Healthcare Workers of a Large COVID-19 Hospital in Rome Reveals Strengths and Limits of Two Different Serological Tests

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18052650 ◽

2021 ◽

Vol 18 (5) ◽

pp. 2650

Author(s):

Giuseppe Vetrugno ◽

Daniele Ignazio La Milia ◽

Floriana D’Ambrosio ◽

Marcello Di Pumpo ◽

Roberta Pastorino ◽

...

Keyword(s):

Blood Test ◽

Healthcare Workers ◽

Point Of Care ◽

Venous Blood ◽

Administrative Staff ◽

Serological Tests ◽

Predictive Values ◽

Work From Home ◽

Significant Difference ◽

Sensitivity Specificity

Healthcare workers are at the forefront against COVID-19, worldwide. Since Fondazione Policlinico Universitario A. Gemelli (FPG) IRCCS was enlisted as a COVID-19 hospital, the healthcare workers deployed to COVID-19 wards were separated from those with limited/no exposure, whereas the administrative staff were designated to work from home. Between 4 June and 3 July 2020, an investigation was conducted to evaluate the seroprevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunoglobulin (IgG) antibodies among the employees of the FPG using point-of-care (POC) and venous blood tests. Sensitivity, specificity, and predictive values were determined with reverse-transcription polymerase chain reaction on nasal/oropharyngeal swabs as the diagnostic gold standard. The participants enrolled amounted to 4777. Seroprevalence was 3.66% using the POC test and 1.19% using the venous blood test, with a significant difference (p < 0.05). The POC test sensitivity and specificity were, respectively, 63.64% (95% confidence interval (CI): 62.20% to 65.04%) and 96.64% (95% CI: 96.05% to 97.13%), while those of the venous blood test were, respectively, 78.79% (95% CI: 77.58% to 79.94%) and 99.36% (95% CI: 99.07% to 99.55%). Among the low-risk populations, the POC test’s predictive values were 58.33% (positive) and 98.23% (negative), whereas those of the venous blood test were 92.86% (positive) and 98.53% (negative). According to our study, these serological tests cannot be a valid alternative to diagnose COVID-19 infection in progress.

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Evaluation of Diagnostic Value in Using a Panel of Multiple Tumor-Associated Antigens for Immunodiagnosis of Cancer

Journal of Immunology Research ◽

10.1155/2014/512540 ◽

2014 ◽

Vol 2014 ◽

pp. 1-7 ◽

Cited By ~ 6

Author(s):

Peng Wang ◽

Chunhua Song ◽

Weihong Xie ◽

Hua Ye ◽

Kaijuan Wang ◽

...

Keyword(s):

Negative Likelihood Ratio ◽

Cyclin B1 ◽

Diagnostic Value ◽

Antibody Detection ◽

Enzyme Linked Immunosorbent Assay ◽

Predictive Values ◽

Multiple Tumor ◽

Tumor Associated Antigens ◽

Cancer Group ◽

Kappa Value

To determine whether a panel of multiple tumor-associated antigens (TAAs) would enhance antibody detection, the diagnostic value of autoantibodies to a panel of multiple TAAs in cancer has been evaluated. The TAAs used in this study was composed of eight TAAs including Imp1, p62, Koc, p53, C-myc, Cyclin B1, Survivin, and p16 full-length recombinant proteins. Enzyme-linked immunosorbent assay and immunoblotting were used to detect antibodies in 304 cancer sera and also 58 sera from normal individuals. The antibody frequency to any individual TAA in cancer was variable but rarely exceeded 20%. With the successive addition of TAAs to a final combination of total of eight antigens, there was a stepwise increase of positive antibody reactions reaching a sensitivity of 63.5% and a specificity of 86.2% in the combined cancer group. In different types of cancer, the ranges of positive and negative likelihood ratio were 4.07–4.76 and 0.39–0.51, respectively, and the ranges of positive and negative predictive values were 74.2–88.7% and 58.8–75.8%, respectively. Agreement rate and Kappa value were 67.1% and 0.51, respectively. These results further support our previous hypothesis that detection of anti-TAAs autoantibodies for diagnosis of certain type of cancer can be enhanced by using a miniarray of several TAAs.

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Increased detection of schistosomiasis with Kato-Katz and SWAP-IgG-ELISA in a Northeastern Brazil low-intensity transmission area

Revista da Sociedade Brasileira de Medicina Tropical ◽

10.1590/s0037-86822012000400019 ◽

2012 ◽

Vol 45 (4) ◽

pp. 510-513 ◽

Cited By ~ 17

Author(s):

Teiliane Rodrigues Carneiro ◽

Marta Cristhiany Cunha Pinheiro ◽

Sara Menezes de Oliveira ◽

Ana Lúcia de Paula Hanemann ◽

José Ajax Nogueira Queiroz ◽

...

Keyword(s):

Serological Test ◽

Laboratory Diagnosis ◽

Elisa Test ◽

Northeastern Brazil ◽

Enzyme Linked Immunosorbent Assay ◽

Serological Tests ◽

Predictive Values ◽

Transmission Area ◽

Elisa Technique ◽

Endemic Areas

INTRODUCTION: The laboratory diagnosis of schistosomiasis is based mainly on the detection of parasite eggs in stool samples through the Kato-Katz (KK) technique, reading one slide by test. However, a widely known limitation of parasitological methods is reduced sensitivity, particularly in low endemic areas. METHODS: To increase sensitivity, we conducted further slide readings from the same stool sample using the parasitological method associated with a serological test. We used the KK method (three slides) and the IgG anti-Schistosoma mansoni-enzyme-linked immunosorbent assay (ELISA) technique to diagnose schistosomiasis in low endemic areas in the Brazilian State of Ceará. Fecal samples and sera from 250 individuals were analyzed. RESULTS: Sixteen percent and 47.2% of samples were positive in parasitological tests and serological tests, respectively. Parasitological methods showed that 32 (80%) individuals tested positive on the first slide, 6 (15%) on the second slide, and 2 (5%) on the third. The performance of the ELISA test in the diagnosis, using the KK method as diagnostic reference, showed a negative predictive value of 100%, with specificity and positive predictive values of 62.8% and 33.9%, respectively. CONCLUSIONS: In this study, the increase from one to three slides analyzed per sample using the KK technique was shown to be a useful procedure for increasing the diagnostic sensitivity of this technique.

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Bayesian evaluation of three serological tests for the diagnosis of bovine brucellosis in Bangladesh

Epidemiology and Infection ◽

10.1017/s0950268818003503 ◽

2019 ◽

Vol 147 ◽

Cited By ~ 5

Author(s):

A. K. M. A. Rahman ◽

S. Smit ◽

B. Devleesschauwer ◽

P. Kostoulas ◽

E. Abatih ◽

...

Keyword(s):

Latent Class ◽

Latent Class Model ◽

Dairy Farm ◽

Agglutination Test ◽

Enzyme Linked Immunosorbent Assay ◽

Bovine Brucellosis ◽

Class Model ◽

Serological Tests ◽

Predictive Values ◽

Conditional Dependence

AbstractWe evaluated the performance of three serological tests – an immunoglobulin G indirect enzyme linked immunosorbent assay (iELISA), a Rose Bengal test and a slow agglutination test (SAT) – for the diagnosis of bovine brucellosis in Bangladesh. Cattle sera (n = 1360) sourced from Mymensingh district (MD) and a Government owned dairy farm (GF) were tested in parallel. We used a Bayesian latent class model that adjusted for the conditional dependence among the three tests and assumed constant diagnostic accuracy of the three tests in both populations. The sensitivity and specificity of the three tests varied from 84.6% to 93.7%, respectively. The true prevalences of bovine brucellosis in MD and the GF were 0.6% and 20.4%, respectively. Parallel interpretation of iELISA and SAT yielded the highest negative predictive values: 99.9% in MD and 99.6% in the GF; whereas serial interpretation of both iELISA and SAT produced the highest positive predictive value (PPV): 99.9% in the GF and also high PPV (98.9%) in MD. We recommend the use of both iELISA and SAT together and serial interpretation for culling and parallel interpretation for import decisions. Removal of brucellosis positive cattle will contribute to the control of brucellosis as a public health risk in Bangladesh.

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Sensitivity, Specificity and Predictive Values of Molecular and Serological Tests for COVID-19: A Longitudinal Study in Emergency Room

Diagnostics ◽

10.3390/diagnostics10090669 ◽

2020 ◽

Vol 10 (9) ◽

pp. 669 ◽

Cited By ~ 4

Author(s):

Zeno Bisoffi ◽

Elena Pomari ◽

Michela Deiana ◽

Chiara Piubelli ◽

Niccolò Ronzoni ◽

...

Keyword(s):

Emergency Room ◽

Latent Class ◽

Single Gene ◽

Molecular Test ◽

Clinical Context ◽

Serological Tests ◽

Predictive Values ◽

Molecular Tests ◽

Sensitivity Specificity

Background: We assessed the sensitivity, specificity and positive and negative predictive value (PPV and NPV) of molecular and serological tests for the diagnosis of SARS-CoV-2 infection. Methods: A total of 346 patients were enrolled in the emergency room. We evaluated three Reverse Transcriptase-real time PCRs (RT-PCRs) including six different gene targets, five serologic rapid diagnostic tests (RDT) and one ELISA. The final classification of infected/non-infected patients was performed using Latent Class Analysis combined with clinical re-assessment of incongruous cases. Results: Out of these, 24.6% of patients were classified as infected. The molecular test RQ-SARS-nCoV-2 showed the highest performance with 91.8% sensitivity, 100% specificity, 100.0% PPV and 97.4% NPV respectively. Considering the single gene targets, S and RdRp of RQ-SARS-nCoV-2 had the highest sensitivity (94.1%). The in-house RdRp presented the lowest sensitivity (62.4%). The specificity ranged from 99.2% for in-house RdRp and N2 to 95.0% for E. The PPV ranged from 97.1% of N2 to 85.4% of E and the NPV from 98.1% of S to 89.0% of in-house RdRp. All serological tests had < 50% sensitivity and low PPV and NPV. VivaDiag IgM (RDT) had 98.5% specificity, with 84.0% PPV, but 24.7% sensitivity. Conclusion: Molecular tests for SARS-CoV-2 infection showed excellent specificity, but significant differences in sensitivity. Serological tests have limited utility in a clinical context.

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FEV1/FEV6: A Reliable, Easy-to-Use, and Cheaper Alternative to FEV1/FVC in Diagnosing Airway Obstruction in Indian Population

ISRN Pulmonology ◽

10.5402/2012/109295 ◽

2012 ◽

Vol 2012 ◽

pp. 1-5 ◽

Cited By ~ 1

Author(s):

Anupam Kumar Singh ◽

Amit Lohia

Keyword(s):

Airway Obstruction ◽

Gold Standard ◽

Indian Population ◽

Area Under The Curve ◽

Predictive Values ◽

Tertiary Centre ◽

Kappa Value ◽

Sensitivity Specificity ◽

Acceptability Criteria ◽

Indian Data

Background. FEV1/FEV6 has been proposed as a cheap, reproducible and valid alternative to FEV1/FVC in spirometry. No Indian data exists on its utility to diagnose airway obstruction. Aim. we sought to determine a fixed cut off of FEV1/FEV6 to diagnose obstruction corresponding to FEV1/FVC < 0.70 proposed by GOLD guidelines. Method. Spirometry was done on patient referred to a tertiary centre in India. Age, sex, height weight were recorded in addition to spirometric variables like FEV1, FVC, FEV6. The sensitivity, specificity, positive and negative predictive values of FEV1/FEV6 were determined with respect to gold standard of FEV1/FVC < 0.70. Results. 467 spirometries were analysed after meeting the ATS acceptability criteria. Considering FEV1/FVC < 0.7 as being the gold standard for obstruction, ROC curve was used to determine the best corresponding cut-off for FEV1/FEV6. The area under the curve was 99.3% (95% CI: 98.1–99.8%), and the FEV1/FEV6 cut-off, corresponding to the greatest sum of sensitivity and specificity, was 73%. For the total population, the FEV1/FEV6 sensitivity, specificity, PPV, NPV were was 95.7 %, 94.2 %, 87.5 % and 97.9 % respectively. Agreement by Kappa value between two cut offs was excellent 0.89 (0.87–0.91). Conclusion. FEV1/FEV6 < 73% is a new reliable spirometry index to diagnose airway obstruction in Indian population.

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Evaluation of a Novel Enzyme-Linked Immunosorbent Assay To Detect Immunoglobulin G Antibody to Enolase for Serodiagnosis of Invasive Candidiasis

Clinical and Vaccine Immunology ◽

10.1128/cvi.00396-06 ◽

2007 ◽

Vol 14 (3) ◽

pp. 318-319 ◽

Cited By ~ 24

Author(s):

Ana Laín ◽

María D. Moragues ◽

Juan Carlos García Ruiz ◽

Joaquín Mendoza ◽

Ana Camacho ◽

...

Keyword(s):

Candida Albicans ◽

Immunosorbent Assay ◽

Immunoglobulin G ◽

Invasive Candidiasis ◽

Enzyme Linked Immunosorbent Assay ◽

Predictive Values ◽

Sensitivity Specificity ◽

Immunocompetent Patients

ABSTRACT The performance of a new test to detect antibodies to Candida albicans recombinant enolase was investigated in 47 immunocompromised and 51 immunocompetent patients. The sensitivity, specificity, and positive and negative predictive values of the test for the diagnosis of invasive candidiasis were 81.0, 83.9, 79.1, and 85.5%, respectively.

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