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PLoS Neglected Tropical Diseases Feb 2023This study aims to evaluate the efficacy of the standard agglutination test (SAT), the Brucellacapt test and enzyme-linked immunosorbent assay (ELISA) in clinical...
BACKGROUND
This study aims to evaluate the efficacy of the standard agglutination test (SAT), the Brucellacapt test and enzyme-linked immunosorbent assay (ELISA) in clinical specimens collected from patients with suspected brucellosis.
METHODS
A prospective study was conducted from December 2020 to December 2021. Brucellosis was diagnosed on the basis of clinical evidence, and confirmed by isolation of Brucella or a four-fold rise in SAT titer. All samples were tested by the SAT, ELISA and the Brucellacapt test. Titers ≥1:100 were considered as SAT positive; ELISA was considered positive when an index greater than 11 was detected, while titers ≥1/160 indicated positivity on the Brucellacapt test. The specificity, sensitivity, and positive (PPVs) and negative predictive values (NPVs) of the three different methods were calculated.
RESULTS
A total of 149 samples were collected from patients with suspected brucellosis. The sensitivities for the SAT, IgG, and IgM detection were 74.42%, 88.37% and 74.42%, respectively. The specificities were 95.24%, 93.65%, and 88.89%, respectively. The simultaneous measurement of IgG and IgM improved the sensitivity (98.84%) but reduced the specificity (84.13%) compared to each antibody test separately. The Brucellacapt test had excellent specificity (100%) and a high PPV (100%); however, the sensitivity and NPV were 88.37% and 86.30%, respectively. The combination of IgG detection by ELISA and the Brucellacapt test had excellent diagnostic performance, with 98.84% sensitivity and 93.65% specificity.
CONCLUSION
This study showed that the simultaneous performance of IgG detection by ELISA and the Brucellacapt test has the potential to overcome the current limitations of detection.
Topics: Humans; Prospective Studies; Antibodies, Bacterial; Brucellosis; Agglutination Tests; Enzyme-Linked Immunosorbent Assay; Immunoglobulin G; Immunoglobulin M; Sensitivity and Specificity
PubMed: 36802393
DOI: 10.1371/journal.pntd.0011131 -
Veterinary Clinical Pathology Dec 2019The appropriate cutoff to define a positive point-of-care card agglutination (CA) test for dog erythrocyte antigen 1 (DEA 1) blood typing depends on whether the test can...
A card agglutination test for dog erythrocyte antigen 1 (DEA 1) blood typing in donor dogs: Determining an appropriate cutoff to detect positivity using a receiver operating characteristic curve.
BACKGROUND
The appropriate cutoff to define a positive point-of-care card agglutination (CA) test for dog erythrocyte antigen 1 (DEA 1) blood typing depends on whether the test can be used in the donor or recipient.
OBJECTIVES
By screening for CA test positivity, we aimed to evaluate the best cutoff value for DEA 1 blood typing in canine blood donors using a receiver operator characteristic (ROC) curve.
METHODS
Ethylenediaminetetraacetic acid (EDTA) blood samples from 100 canine blood donors were blood-typed in parallel for DEA 1 using both immunochromatographic (IC) and CA tests. The effect of temperature, storage time, and anticoagulant solutions for both methods was evaluated. Unweighted and weighted Cohen's Kappa (K) statistic was calculated to evaluate the agreement between the two testing methods. The overall performance of the CA test was evaluated by generating a ROC curve using the IC test as the reference method.
RESULTS
Concordant results were obtained for 86% of the samples. Unweighted and weighted K statistics demonstrated good and moderate agreement, respectively. For the CA test, the ROC curve showed an area under the curve (AUC) of 0.910, with the highest sensitivity cutoff values at ≥1+ agglutination. CA- and IC-typed EDTA blood samples stored at room temperature for up to 1 week and refrigerated for up to 1 month were concordant as were the citrate phosphate dextrose adenine 1 (CPDA-1) anticoagulated blood samples stored for up to 1 week at 4 ± 2°C.
CONCLUSIONS
The overall reliability of the CA method seemed to be lower than that of the IC method. When CA is used as a screening test for canine blood donors, the correct cut off is ≥1+ agglutination is recommended to maximize sensitivity.
Topics: Agglutination Tests; Animals; Blood Group Antigens; Blood Grouping and Crossmatching; Chromatography, Affinity; Dogs; Female; Male; ROC Curve; Reproducibility of Results
PubMed: 31650574
DOI: 10.1111/vcp.12788 -
Preventive Veterinary Medicine Apr 2022Toxoplasma gondii infection in pigs is commonly diagnosed using serological tests that detect IgG antibodies targeted against the parasite. Such tests include...
Determination of an optimal ELISA cut-off for the diagnosis of Toxoplasma gondii infection in pigs using Bayesian latent class modelling of data from multiple diagnostic tests.
Toxoplasma gondii infection in pigs is commonly diagnosed using serological tests that detect IgG antibodies targeted against the parasite. Such tests include enzyme-linked immunosorbent assay (ELISA), modified agglutination test (MAT), and western blot (WB), which are commercially available as rapid test kits. In this study, we evaluated the manufacturer recommended cut-off of ELISA-PrioCHECK test kit and determined a new optimal cut-off for identifying T. gondii infections in pigs. Assessment of the commercial ELISA kit was done by including data from two additional serological tests, MAT, and WB, applied to seven pig population categories with varying prevalences. A total of 233 plasma samples that were previously used in other studies for investigating T. gondii seroprevalence in pigs in Denmark were randomly selected for inclusion, including 95 samples that had previously been analysed with all three tests and an additional 138 samples that were analysed using the three serological tests for this study. In the absence of a gold standard test, a latent class model was fit to the data to obtain estimates of sensitivity and specificity for each of the tests along with prevalence in each of the populations. A cut-off that maximized the sensitivity and specificity of the ELISA test was then selected. The optimal cut-off value for percent of positive control (PP) in ELISA-PrioCHECK was estimated to be 27.7 PP, which is higher than the cut-off value of 20 PP that is recommended by the manufacturer. At this cut-off, the estimated sensitivities of ELISA, MAT and WB were 99.2% (96.3-100.0%), 96.3% (88.0-100.0%), and 89.8% (80.0-98.0%), respectively. The estimated specificities of ELISA, MAT and WB were 95.2% (92.5-97.6%), 99.6% (97.5-100.0%), and 98.2% (95.9-100.0%), respectively. Our findings have broad relevance to the use of the ELISA-PrioCHECK test kit for detecting Toxoplasma gondii infection in pigs.
Topics: Agglutination Tests; Animals; Antibodies, Protozoan; Bayes Theorem; Diagnostic Tests, Routine; Enzyme-Linked Immunosorbent Assay; Seroepidemiologic Studies; Swine; Toxoplasma; Toxoplasmosis, Animal
PubMed: 35286870
DOI: 10.1016/j.prevetmed.2022.105606 -
Poultry Science Dec 2019Pullorum disease caused by Salmonella Pullorum is one of the most important infectious diseases in the poultry industry worldwide, which leads to serious economic losses... (Comparative Study)
Comparative Study
Pullorum disease caused by Salmonella Pullorum is one of the most important infectious diseases in the poultry industry worldwide, which leads to serious economic losses in many developing countries because of its high mortality rate in young chicks. The traditional slide agglutination test with low cost, fast reaction, and on-site detection has been widely used in the diagnosis of Pullorum disease. However, in practice, the test performance is with the disadvantages of false positive results and unstable detection results. In this paper, we developed self-made agglutination antigens prepared by local isolates in the poultry farm and compare the detection performance with commercial agglutination antigens (China Institute of Veterinary Drug Control) and Group D Salmonella ELISA kit (BioChek UK Ltd). The results of detecting 200 serum samples indicated that the consistency of commercial agglutination antigen detecting in 2 times was only 79.5%. Using the ELISA kit as the reference method, the commercial agglutination antigen detecting results of the Kappa test were only moderately consistent (0.58 ∼ 0.59). Meanwhile, positive and total coincidence rates of the self-made agglutination antigen test with more reliable repeat could reach 97.4 and 88%, respectively, and the result of Kappa test was highly consistent (0.75). The Receiver Operating Characteristic curve analysis clarified that the area under the receiver-operating-characteristic curve values of self-made and commercial agglutination antigen tests could reach 0.861 and 0.804, respectively. These results were coincident when detecting known positive serum from the infected chickens. It's worth mentioning that the visible positive reaction of self-made agglutination antigen test appeared faster and stronger than commercial antigen test. In conclusion, self-made Salmonella Pullorum agglutination antigen developed in this study was much better than commercial agglutination antigen and is expected to be a valuable tool in the diagnosis of the epidemiology of Salmonella Pullorum.
Topics: Agglutination Tests; Animals; Antigens, Bacterial; Chickens; Enzyme-Linked Immunosorbent Assay; Poultry Diseases; Salmonella; Salmonella Infections, Animal
PubMed: 31399741
DOI: 10.3382/ps/pez453 -
International Journal of Medical... 2011Different serological tests are used in serologic diagnosis of brucellosis. The most widely used of these are Standard Tube Agglutination and Coombs anti-brucella tests....
BACKGROUND
Different serological tests are used in serologic diagnosis of brucellosis. The most widely used of these are Standard Tube Agglutination and Coombs anti-brucella tests. Whereas ELISA Ig M and Ig G tests have been in use for a long time, immuncapture agglutination test has been recently introduced and used in serological diagnosis. The aim of this study was to compare diagnostic values of ELISA Ig M and Ig G and immuncapture agglutination tests with Coombs anti-brucella test.
METHODS
Sera from 200 patients with presumptive diagnosis of brucellosis were included into the study. Coombs anti-brucella test, ELISA Ig M and Ig G tests and Immuncapture test were investigated in these sera. Then, sensitivity, specificity, negative predictive and positive predictive values were calculated.
RESULTS
Sensitivity, specificity, negative predictive and positive predictive values were found to be 90.6%, 76.3%, 94.2%, and 65.9% respectively for the Immuncapture test, whereas they were found to be 73.7%, 58.9%, 84.2%, and 42.8% for Ig G and 72.2%, 67.8%, 85.2%, and 48.7% for Ig M. The Immuncapture test was found to be compatible with ELISA Ig M and Ig G tests but it was statistically incompatible with Coombs anti-brucella test.
CONCLUSIONS
Immuncapture agglutination test yields similar results to those of Coombs anti-brucella test. This test is a useful test by virtue of the fact that it determines blocking antibodies in the diagnosis and follow-up of brucellosis.
Topics: Adult; Agglutination Tests; Antibodies, Bacterial; Antibody Affinity; Brucella; Brucellosis; Coombs Test; Enzyme-Linked Immunosorbent Assay; Female; Humans; Immunoglobulin G; Immunoglobulin M; Male; Middle Aged; Predictive Value of Tests; Sensitivity and Specificity
PubMed: 21814476
DOI: 10.7150/ijms.8.428 -
Revista Argentina de Microbiologia 2020Leptospirosis is considered an endemic disease in Buenos Aires province, Argentina, with human cases reported annually from rural and urban areas. The aim of the study...
Leptospirosis is considered an endemic disease in Buenos Aires province, Argentina, with human cases reported annually from rural and urban areas. The aim of the study was to describe the variables that influence the delay in the serological confirmation of leptospirosis in human cases (period 2006-2014) from Buenos Aires province. Sixty-four percent (64%) of cases could be confirmed by microscopic agglutination test (MAT) with the first sample. The time of confirmation of the human leptospirosis cases was on average 21 days from the onset of the first clinical signs, and varied depending on the distance of the different sanitary regions. The geographical distribution of the confirmed leptospirosis human cases, in addition to the high number of suspected cases and probable cases (which could not be confirmed by MAT), demonstrate that leptospirosis is endemic and underreported in Buenos Aires province, and that distance and lack of resources could be determinant factors of this situation.
Topics: Agglutination Tests; Argentina; Endemic Diseases; Humans; Leptospirosis
PubMed: 31959371
DOI: 10.1016/j.ram.2019.11.005 -
Acta Veterinaria Scandinavica Feb 2012The aim of this study was to compare a gel-based test with the traditional direct agglutination test (DAT) for the diagnosis of immune-mediated haemolytic anaemia (IMHA).
BACKGROUND
The aim of this study was to compare a gel-based test with the traditional direct agglutination test (DAT) for the diagnosis of immune-mediated haemolytic anaemia (IMHA).
METHODS
Canine (n = 247) and feline (n = 74) blood samples were submitted for DAT testing to two laboratories. A subset of canine samples was categorized as having idiopathic IMHA, secondary IMHA, or no IMHA.
RESULTS
The kappa values for agreement between the tests were in one laboratory 0.86 for canine and 0.58 for feline samples, and in the other 0.48 for canine samples. The lower agreement in the second laboratory was caused by a high number of positive canine DATs for which the gel test was negative. This group included significantly more dogs with secondary IMHA.
CONCLUSIONS
The gel test might be used as a screening test for idiopathic IMHA and is less often positive in secondary IMHA than the DAT.
Topics: Agglutination Tests; Anemia, Hemolytic, Autoimmune; Animals; Cat Diseases; Cats; Dog Diseases; Dogs; Gels
PubMed: 22316049
DOI: 10.1186/1751-0147-54-10 -
The American Journal of Tropical... May 2012In areas where visceral leishmaniasis is anthroponotic, asymptomatically infected patients may play a role in transmission. Additionally, the number of asymptomatic...
Usefulness of the rK39-immunochromatographic test, direct agglutination test, and leishmanin skin test for detecting asymptomatic Leishmania infection in children in a new visceral leishmaniasis focus in Amhara State, Ethiopia.
In areas where visceral leishmaniasis is anthroponotic, asymptomatically infected patients may play a role in transmission. Additionally, the number of asymptomatic patients in a disease-endemic area will also provide information on transmission dynamics. Libo Kemkem and Fogera districts (Amhara State, Ethiopia) are now considered newly established areas to which visceral leishmaniasis is endemic. In selected villages in these districts, we conducted a study to assess the usefulness of different approaches to estimate the asymptomatic infection rate. Of 605 participants, the rK39 immunochromatographic test was able to detect asymptomatic infection in 1.5% (9 of 605), direct agglutination test in 5.3% (32 of 605), and leishmanin skin test in 5.6% (33 of 589); the combined use of serologic methods and leishmanin skin test enabled detecting asymptomatic infection in 10.1% (61 of 605). We conclude that the best option to detect asymptomatic infection in this new visceral leishmaniasis-endemic focus is the combined use of the direct agglutination test and the leishmanin skin test.
Topics: Adolescent; Agglutination Tests; Antigens, Protozoan; Asymptomatic Infections; Child; Child, Preschool; Chromatography, Affinity; Endemic Diseases; Ethiopia; Female; Humans; Leishmania; Leishmaniasis, Visceral; Male; Skin Tests
PubMed: 22556076
DOI: 10.4269/ajtmh.2012.11-0196 -
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 -
Clinical and Diagnostic Laboratory... Jul 1998Current serologic tests used to detect antibodies to Neospora caninum require species-specific secondary antibodies, limiting the number of species that can be tested.... (Comparative Study)
Comparative Study
A modified agglutination test for Neospora caninum: development, optimization, and comparison to the indirect fluorescent-antibody test and enzyme-linked immunosorbent assay.
Current serologic tests used to detect antibodies to Neospora caninum require species-specific secondary antibodies, limiting the number of species that can be tested. In order to examine a wide variety of animal species that may be infected with N. caninum, a modified direct agglutination test (N-MAT) similar to the Toxoplasma gondii modified direct agglutination test (T-MAT) was developed. This test measures the direct agglutination of parasites by N. caninum-specific antibodies in serum, thus eliminating the need for secondary host-specific anti-isotype sera. The N-MAT was compared to the indirect fluorescent-antibody test (IFAT) and the enzyme-linked immunosorbent assay (ELISA) with a "gold standard" serum panel from species for which secondary antibodies were available (n = 547). All positive samples tested were from animals with histologically confirmed infections. Up to 16 different species were tested. The N-MAT gave a higher sensitivity (100%) and specificity (97%) than the ELISA (74 and 94%, respectively) and had a higher sensitivity but a lower specificity than the IFAT (98 and 99%, respectively). The reduced specificity of the N-MAT was due to false-positive reactions in testing fetal fluids with particulate matter or severely hemolyzed serum. Overall, the N-MAT proved to be highly sensitive and specific for both naturally and experimentally infected animals, highly reproducible between and within readers, easy to use on large sample sizes without requiring special equipment, and useful in testing serum from any species without modification.
Topics: Abortion, Veterinary; Agglutination Tests; Animals; Antibodies, Protozoan; Cattle; Cattle Diseases; Coccidiosis; Enzyme-Linked Immunosorbent Assay; Evaluation Studies as Topic; Female; Fluorescent Antibody Technique, Indirect; Neospora; Predictive Value of Tests; Pregnancy; Sensitivity and Specificity; Species Specificity
PubMed: 9665950
DOI: 10.1128/CDLI.5.4.467-473.1998