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BMC Research Notes Jul 2021Canine visceral leishmaniasis (CVL) is the main source of human visceral leishmaniosis (HVL) in Mediterranean region, including Iran and is spread from domestic dogs to...
OBJECTIVE
Canine visceral leishmaniasis (CVL) is the main source of human visceral leishmaniosis (HVL) in Mediterranean region, including Iran and is spread from domestic dogs to Phlebotomine sand flies vectors to humans. To control the transmission of HVL, early and accurate detection of infected dogs is paramount importance despite it remains a confronting challenge. Herein, we evaluated the performance of direct agglutination test (DAT) against gold standard nested polymerase chain reaction (nested-PCR) for CVL diagnosis in symptomatic and asymptomatic domestic dogs from endemic areas of Iran.
RESULTS
Venous blood samples were collected from dogs without clinical signs (n = 30) and with clinical signs (n = 35) suggestive of Leishmania infantum infection. Among 65 samples examined, Leishmania DNA was detected by nested-PCR in 89.23% (58/65). Furthermore, 86.15% (56/65) nested-PCR positive samples were also DAT positive. The results of the DAT sensitivity test were 96.43% and 96.67% in symptomatic and asymptomatic dogs, respectively, while the specificity was 100.00% and 60.00% in symptomatic and asymptomatic dogs, respectively. The results of this study also pointed out substantial concordance between DAT test and nested-PCR method in both symptomatic dogs (Κ = 0.783; P < 0.001) and asymptomatic dogs (Κ = 0.618; P < 0.001). Thus, DAT represents as a simple and economic tool for initial diagnosis of CVL particularly in endemic areas of the disease.
Topics: Agglutination Tests; Animals; Antibodies, Protozoan; DNA, Protozoan; Dog Diseases; Dogs; Iran; Leishmania infantum; Leishmaniasis, Visceral; Polymerase Chain Reaction
PubMed: 34256817
DOI: 10.1186/s13104-021-05654-0 -
ACS Applied Materials & Interfaces Jan 2022Rapid serology platforms are essential in disease pandemics for a variety of applications, including epidemiological surveillance, contact tracing, vaccination...
Rapid serology platforms are essential in disease pandemics for a variety of applications, including epidemiological surveillance, contact tracing, vaccination monitoring, and primary diagnosis in resource-limited areas. Laboratory-based enzyme-linked immunosorbent assay (ELISA) platforms are inherently multistep processes that require trained personnel and are of relatively limited throughput. As an alternative, agglutination-based systems have been developed; however, they rely on donor red blood cells and are not yet available for high-throughput screening. Column agglutination tests are a mainstay of pretransfusion blood typing and can be performed at a range of scales, ranging from manual through to fully automated testing. Here, we describe a column agglutination test using colored microbeads coated with recombinant SARS-CoV-2 spike protein that agglutinates when incubated with serum samples collected from patients recently infected with SARS-CoV-2. After confirming specific agglutination, we optimized centrifugal force and time to distinguish samples from uninfected vs SARS-CoV-2-infected individuals and then showed concordant results against ELISA for 22 clinical samples, and also a set of serial bleeds from one donor at days 6-10 postinfection. Our study demonstrates the use of a simple, scalable, and rapid diagnostic platform that can be tailored to detect antibodies raised against SARS-CoV-2 and can be easily integrated with established laboratory frameworks worldwide.
Topics: Agglutination Tests; Antibodies, Viral; COVID-19 Serological Testing; Diagnostic Tests, Routine; Early Diagnosis; Humans; Recombinant Proteins; Sensitivity and Specificity; Spike Glycoprotein, Coronavirus
PubMed: 34990107
DOI: 10.1021/acsami.1c17859 -
Infectious Diseases of Poverty Mar 2021Brucellosis is an infectious-allergic zoonotic disease caused by bacteria of the genus Brucella. Early diagnosis is the key to preventing, treating, and controlling...
BACKGROUND
Brucellosis is an infectious-allergic zoonotic disease caused by bacteria of the genus Brucella. Early diagnosis is the key to preventing, treating, and controlling brucellosis. Fluorescence polarization immunoassay (FPA) is a new immunoassay for relatively rapid and accurate detection of antibodies or antigens based on antigen-antibody interaction. However, there is no report on FPA-based detection of human brucellosis in China. Therefore, this study is to evaluate the value of FPA for the diagnosis of human brucellosis in China.
METHODS
We recruited 320 suspected brucellosis cases who had the clinical symptoms and epidemiological risk factors between January and December, 2019. According to China Guideline for Human Brucellosis Diagnosis, the Rose Bengal test (RBT) was used for the screening test, and the serum agglutination test (SAT) was used as the confirmatory test. Brucellosis was confirmed only if the results of both tests were positive. Additionally, FPA and enzyme linked immune sorbent assay (ELISA) were compared with SAT, and their sensitivity, specificity, coincidence rate and consistency coefficient (Kappa value) as diagnostic tests were analyzed individually and in combination. The optimal cut-off value of FPA was also determined using the receiver operator characteristic (ROC) curve.
RESULTS
The optimum cut-off value of FPA was determined to be 88.5 millipolarization (mP) units, with a sensitivity of 94.5% and specificity of 100.0%. Additionally, the coincidence rate with the SAT test was 96.6%, and the Kappa value (0.9) showed excellent consistency. The sensitivity and specificity of FPA and ELISA combined were higher at 98.0% and 100.0% respectively.
CONCLUSIONS
When the cut-off value of FPA test is set at 88.5 mP, it has high value for the diagnosis of brucellosis. Additionally, when FPA and ELISA are combined, the sensitivity of diagnosis is significantly improved. Thus, FPA may have potential in the future as a diagnostic method for human brucellosis in China.
Topics: Agglutination Tests; Antibodies, Bacterial; Brucella; Brucellosis; Enzyme-Linked Immunosorbent Assay; Fluorescence Polarization Immunoassay; Humans; ROC Curve; Sensitivity and Specificity
PubMed: 33789762
DOI: 10.1186/s40249-021-00834-3 -
Preventive Veterinary Medicine Dec 2023When Bayesian latent class analysis is used for diagnostic test data in the absence of a gold standard test, it is common to assume that any unknown test sensitivities...
When Bayesian latent class analysis is used for diagnostic test data in the absence of a gold standard test, it is common to assume that any unknown test sensitivities and specificities are constant across different populations. Indeed this assumption is often necessary for model identifiability. However there are a number of practical situations, depending on the type of test and the nature of the disease, where this assumption may not be true. We present a case study of using a microscopic agglutination test to diagnose leptospiroris infection in beef cattle, which strongly suggests that sensitivity in particular varies among herds. We develop and fit an alternative model in which sensitivity is related to within-herd prevalence, and discuss the statistical and epidemiological implications.
Topics: Cattle; Animals; Bayes Theorem; Leptospirosis; Cattle Diseases; Agglutination Tests; Prevalence; Sensitivity and Specificity
PubMed: 37976969
DOI: 10.1016/j.prevetmed.2023.106074 -
Clinical Laboratory Sep 2020The diagnosis of human brucellosis is difficult based on clinical grounds alone. Thus, the diagnosis is based on microbiological and serological tests. Therefore, the...
BACKGROUND
The diagnosis of human brucellosis is difficult based on clinical grounds alone. Thus, the diagnosis is based on microbiological and serological tests. Therefore, the diagnosis relies predominantly on laboratory testing. The objective of this study was to determine the most efficient test for the diagnosis and monitoring of patients treated for brucellosis by comparing the standard agglutination test in a tube with 2-mercaptoethanol (SAT-2Me) to an enzyme-linked immunosorbent assay for the detection of antibodies against Brucella IgM (IgM ELISA).
METHODS
A retrospective chart review was performed. A total of 108 patients with brucellosis were analyzed at diagnosis and at the first and second follow-ups after treatment. The data were captured and analyzed using the SPSS 18.0 program. Frequencies, percentages, the Pearson's chi-square test, the kappa coefficient, sensitivity, specificity, predictive values, odds ratio, and conditional odds ratio (OR and COR) were calculated.
RESULTS
Diagnostic test: the IgM ELISA showed 96.3% sensitivity vs. 73.1% sensitivity for the SAT-2Me (p < 0.001). First follow-up: the IgM ELISA presented significant differences vs. the SAT-2Me in sensitivity (97.2% vs. 72.2%) and specificity (89.7% vs. 44.1%). Additionally, the second follow-up data showed significant differences in the sensitivity (85.7% vs. 71.4%) and specificity (82.8% vs. 41.4%) for the IgM ELISA vs. the SAT-2Me, re-spectively. In addition, the IgM ELISA showed significant concordance (0.836, p < 0.001 and 0.563, p < 0.001) at the first and second follow-ups, respectively, vs. the SAT-2Me.
CONCLUSIONS
The IgM ELISA is a more reliable and useful assay for the diagnosis and monitoring of brucellosis patients than the SAT-2 Me, avoiding up to 45.6% of unnecessary treatments. The SAT-2Me showed lower efficiency for diagnosis than the IgM ELISA and limited relevance for monitoring.
Topics: Agglutination; Agglutination Tests; Antibodies, Bacterial; Brucella; Brucellosis; Enzyme-Linked Immunosorbent Assay; Humans; Immunoenzyme Techniques; Immunoglobulin M; Mercaptoethanol; Retrospective Studies; Sensitivity and Specificity
PubMed: 32902225
DOI: 10.7754/Clin.Lab.2020.190932 -
Transfusion and Apheresis Science :... Oct 2022Use of fully automated solutions to perform analysis of immunohematology tests is highly desirable as it delivers an improved level of safety and security of results....
INTRODUCTION
Use of fully automated solutions to perform analysis of immunohematology tests is highly desirable as it delivers an improved level of safety and security of results. However, full automation may not be feasible financially and practically in all circumstances. A solution that addresses most of the process step hazards of manual testing can assist in achieving a higher level of confidence in and safety of test results.
METHODS
The study utilized a column agglutination technology (ORTHO BioVue ® System) to test a variety of samples on the ORTHO VISION ® Analyzer and compare to the reader capability of the ORTHO OPTIX™ Reader. Both direct agglutination and direct/indirect antiglobulin test methods were evaluated. The data was analysed for per cent agreement and for concordance at the lower bound 95% confidence interval. The acceptance criteria for concordance for direct agglutination was ≥ 99.4% and for indirect agglutination was ≥ 98.0% at a lower bound 95% confidence interval.
RESULTS
There were 13,805 columns producing 5174 interpreted tests for direct agglutination and 5998 columns producing 2958 interpreted direct/indirect antiglobulin tests evaluated. Testing demonstrated that direct agglutination and direct/indirect antiglobulin testing generated greater than 99% concordance between the fully automated instrument system and the reader.
CONCLUSIONS
The reader exceeded the approval criteria set for the study which demonstrates the capability to address the desire for a solution that moves manual testing to an enhanced level which achieves improved safety and security in immunohematology testing.
Topics: Humans; Coombs Test; Automation; Antibodies, Anti-Idiotypic
PubMed: 35414466
DOI: 10.1016/j.transci.2022.103441 -
BMC Infectious Diseases Feb 2024Leptospirosis is an underdiagnosed infectious disease with non-specific clinical presentation that requires laboratory confirmation for diagnosis. The serologic... (Meta-Analysis)
Meta-Analysis
Diagnosis of human leptospirosis: systematic review and meta-analysis of the diagnostic accuracy of the Leptospira microscopic agglutination test, PCR targeting Lfb1, and IgM ELISA to Leptospira fainei serovar Hurstbridge.
BACKGROUND
Leptospirosis is an underdiagnosed infectious disease with non-specific clinical presentation that requires laboratory confirmation for diagnosis. The serologic reference standard remains the microscopic agglutination test (MAT) on paired serum samples. However, reported estimates of MAT's sensitivity vary. We evaluated the accuracy of four index tests, MAT on paired samples as well as alternative standards for leptospirosis diagnosis: MAT on single acute-phase samples, polymerase chain reaction (PCR) with the target gene Lfb1, and ELISA IgM with Leptospira fainei serovar Hurstbridge as an antigen.
METHODS
We performed a systematic review of studies reporting results of leptospirosis diagnostic tests. We searched eight electronic databases and selected studies that tested human blood samples and compared index tests with blood culture and/or PCR and/or MAT (comparator tests). For MAT selection criteria we defined a threshold for single acute-phase samples according to a national classification of leptospirosis endemicity. We used a Bayesian random-effect meta-analysis to estimate the sensitivity and specificity of MAT in single acute-phase and paired samples separately, and assessed risk of bias using the Quality Assessment of Studies of Diagnostic Accuracy Approach- 2 (QUADAS-2) tool.
RESULTS
For the MAT accuracy evaluation, 15 studies were included, 11 with single acute-phase serum, and 12 with paired sera. Two included studies used PCR targeting the Lfb1 gene, and one included study used IgM ELISA with Leptospira fainei serovar Hurstbridge as antigen. For MAT in single acute-phase samples, the pooled sensitivity and specificity were 14% (95% credible interval [CrI] 3-38%) and 86% (95% CrI 59-96%), respectively, and the predicted sensitivity and specificity were 14% (95% CrI 0-90%) and 86% (95% CrI 9-100%). Among paired MAT samples, the pooled sensitivity and specificity were 68% (95% CrI 32-92%) and 75% (95% CrI 45-93%) respectively, and the predicted sensitivity and specificity were 69% (95% CrI 2-100%) and 75% (2-100%).
CONCLUSIONS
Based on our analysis, the accuracy of MAT in paired samples was not high, but it remains the reference standard until a more accurate diagnostic test is developed. Future studies that include larger numbers of participants with paired samples will improve the certainty of accuracy estimates.
Topics: Humans; Serogroup; Bayes Theorem; Antibodies, Bacterial; Leptospira; Leptospirosis; Agglutination Tests; Sensitivity and Specificity; Enzyme-Linked Immunosorbent Assay; Immunoglobulin M; Polymerase Chain Reaction
PubMed: 38326762
DOI: 10.1186/s12879-023-08935-0 -
Methods in Molecular Biology (Clifton,... 2020Toxoplasma gondii is a protozoan parasite that infects mammals and birds. Molecular epidemiology and population genetic studies have revealed widespread and distinct...
Toxoplasma gondii is a protozoan parasite that infects mammals and birds. Molecular epidemiology and population genetic studies have revealed widespread and distinct distribution of different T. gondii genotypes globally. Animals (domestic and wild) are the reservoirs for transmission of this parasite to humans. Recent development in molecular genotyping methods allowed us to identify parasite strains with high resolution and to dissect transmission patterns among different hosts. However, current data in the literature is still limited and fragmented. Here, we summarize a set of protocols that can be used to identify T. gondii infection in clinically normal animals, isolate the parasite by bioassay using animal tissues, extract parasite DNA from tissue samples, and finally identify the parasite by multilocus PCR-RFLP genotyping. We hope these protocols provide essential tools to study genetic diversity, population structure and transmission dynamics of T. gondii. Accumulation of the information will allow us to better understand, control, and prevent T. gondii infection in the future.
Topics: Agglutination Tests; Biological Assay; Genetic Variation; Genotype; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; Toxoplasma
PubMed: 31758446
DOI: 10.1007/978-1-4939-9857-9_3 -
The Journal of International Medical... Mar 2020The indirect antiglobulin test (IAT) and direct antiglobulin test (DAT) have been used as common tests for transfusion. Recently, we have found that in addition to...
BACKGROUND
The indirect antiglobulin test (IAT) and direct antiglobulin test (DAT) have been used as common tests for transfusion. Recently, we have found that in addition to causing false increases, rheumatoid factor (RF) can also cause false decreases in immunoassays for hepatitis B surface antigen and B-type natriuretic peptide. However, it remains unclear whether RF also interferes with the IAT and DAT.
METHODS
IAT models were produced by mixing IAT-positive plasma and RF-positive plasma, then one-step and two-step IATs were adopted for detection. DAT models were produced by mixing DAT-positive red blood cells (RBCs) and RF-positive plasma, followed by detection with the DAT. The DAT models were diluted using the same RF-positive plasma, and the DAT was performed again.
RESULTS
The rate of decrease of the two-step IAT (40.63%) was significantly higher than that of the one-step IAT (31.51%). Both the rate of decrease (76.67%) and increase (16.67%) of the results of the 60 DAT models were significantly higher than those of the IAT models after two-fold dilution.
CONCLUSIONS
The RF can lead to both false decreases and false increases in IAT and DAT. And the interference effects are related to the RF content relative to the IgG-sensitized RBCs.
Topics: Blood Transfusion; Coombs Test; Erythrocytes; Rheumatoid Factor
PubMed: 31854210
DOI: 10.1177/0300060519892386 -
Parasitology International Feb 2023An in-house enzyme-linked immunosorbent assay (ELISA) based on crude antigen of Leishmania reported a high sero-prevalence (82.0%) in Leishmania donovani induced...
An in-house enzyme-linked immunosorbent assay (ELISA) based on crude antigen of Leishmania reported a high sero-prevalence (82.0%) in Leishmania donovani induced cutaneous leishmaniasis (CL) in Sri Lanka. ELISA was further compared with established serological tools to identify a suitable point of care diagnostic tool. Sero-prevalence of 100 CL samples were analyzed using in-house ELISA, Indian dipstick test and rK39 strip test. Results obtained were further compared with direct agglutination test (DAT) for 40 CL. Test performance was evaluated using Kappa index value. Clinico-epidemiological characteristics of patients were analyzed using SPSSv25.0. Cost analysis of tests was carried out. ELISA showed a high sero-positivity of 81.0% (n = 81/100) while DAT (57.5%,n = 23/40), Indian dipstick test (22.0%,n = 22/100) and rK39 test (15.0%,n = 15/100) showed a comparatively less sero-positivity. According to Kappa index values, there were no perfect agreement between tests. Among ELISA positive patients (n = 81/100), DAT, Indian dipstick test and rK39 demonstrated sero-positivity rates of 61.3% (n = 19/31), 25.9% (n = 21/81) and 16.0% (n = 13/81) respectively. Among ELISA negative patients (n = 19/100), three assays demonstrated sero-positivity rates of 44.4% (n = 4/9), 5.3% (n = 1/9) and 10.5% (n = 2/19) respectively. DAT can be used as an alternative test when ELISA is not available or negative. Clinico-epidemiological profiles of patients that showed sero-positivity by each assay were different. Cost per patient was approximately 5.5 USD for DAT and 3.0 USD for each other tests. Established serological tests demonstrated different and relatively lower detection rates. Species, strain and antigen heterogeneity, inconsistency in amount of used antigens, sera, antibody expression patterns and testing methodologies could be responsible. This study highlighted the importance of designing an in-house serological assay based on local parasite.
Topics: Humans; Leishmania donovani; Prevalence; Leishmaniasis, Cutaneous; Hematologic Tests; Agglutination Tests
PubMed: 36038060
DOI: 10.1016/j.parint.2022.102660