Detection of Anti-LipL32 Antibodies in Serum Samples from Horses with Chronic Intraocular Infection with Leptospira spp.

Equine recurrent uveitis (ERU) is typically caused by chronic intraocular leptospiral infection in warm-blooded horses in central Europe. The most effective therapy for leptospiral-induced ERU is the surgical removal of diseased vitreous (vitrectomy). Since vitrectomy is a highly specialized and invasive surgery, the indication must be determined very carefully. In order to obtain evidence of intraocular leptospiral infection by laboratory diagnostics in questionable leptospiral ERU-cases, sampling of aqueous humor is required, because serum tests using microscopic agglutination test (MAT) are too unspecific. The SNAP Lepto is a cross-species rapid test for the detection of anti-Lipl32 antibodies that has a high sensitivity (0.97) and specificity (1.00) for the detection of anti-leptospiral antibodies using aqueous humor or vitreous samples, which is comparable to MAT. To evaluate sensitivity and specificity of SNAP Lepto using serum, serum samples from 90 horses with confirmed leptospiral ERU and from 103 ocularly healthy horses were tested by both MAT and SNAP Lepto. Sensitivity was similar for both tests (0.82 vs. 0.79), but specificity was lower for MAT (0.52 vs. 0.95). Sensitivity and specificity are therefore lower in serum samples compared to intraocular samples, however, the SNAP Lepto is far superior to MAT and suitable as a screening method using equine serum.

Download Full-text

Assessment of serological tests for antibodies to different antigens of the SARS-CoV-2 virus: comparison of six immunoassays

Medical Immunology (Russia) ◽

10.15789/1563-0625-aos-2228 ◽

2021 ◽

Vol 23 (6) ◽

pp. 1395-1404

Author(s):

V. V. Belyakova ◽

O. A. Maiorova ◽

N, V. Ivanova ◽

I. E. Stepanova ◽

M. A. Smerdova ◽

...

Keyword(s):

Sensitivity And Specificity ◽

Rapid Test ◽

Diagnostic Methods ◽

Federal State ◽

Control Group ◽

Laboratory Diagnostics ◽

Igg Antibodies ◽

Diagnostic Systems ◽

Serum Samples ◽

Serological Tests

The new coronavirus SARS-CoV-2 has become a global challenge to medicine and, in particular, laboratory diagnostics. The study of the antibodies’ level to SARS-CoV-2 can be used as a confirmation test in the diagnosis of a disease, but it becomes of paramount importance in assessing population immunity resulting from a disease or vaccination, as well as in selection of convalescent plasma donors. The kits developed in our country and abroad for detecting antibodies to the SARS-CoV-2 virus differ both in the methods of testing and in the used coronavirus antigens to which the antibodies are directed. The aim of this study was to compare the diagnostic sensitivity and specificity of five kits for the detection of IgG antibodies to the SARS-CoV-2 virus, based on different diagnostic methods. Serum samples from 137 COVID-19 convalescents and 166 donors of blood and its components were examined. The control group consisted of 50 blood sera collected at the beginning of 2019 and 19 sera collected in 2018 (before the advent of the SARS-CoV-2 virus) and stored at -70 °C. Testing was carried out in analytical systems: rapid test “COVID-19 IgM/IgG Rapid Test (Colloidal Gold)” (China), on an automatic immunochemical analyzer Abbott Architect™ i2000 and kit “SARS-CoV2-IgG” (Abbot, Chicago , IL USA), by the chemiluminescence method using an automatic analyzer of the CL series and kits of the “Mindray” company (China) “SARS-CoV-2 IgM” and “SARS-CoV-2 IgG” and by the enzyme immunoassay method on the kits of the companies “Diagnostic Systems” Ltd (Russia, Nizhny Novgorod) “DS-IFA-ANTI-SARS-CoV-2-G”, “Xema” Ltd (Federal State Budgetary Institution “National Medical Research Center of Hematology” of the Ministry of Health of Russia) “SARS-CoV-2-IgG-IFA” and “Vector-Best” CJSC (Russia, Novosibirsk)” SARS-COV-2-IgM-IFA-BEST” and “SARS-COV-2-IgG-IFABEST”. When comparing the results of testing 137 plasma samples on the Vector-Best and Mindray kits for IgG antibodies, 127 samples were positive, 7 samples were negative on both kits, the discrepancy was 2.2%. In the study of IgM antibodies, 32.1% were positive, and 52.6% were negative in both kits. The discrepancy rate was 15.3%. Out of 166 samples, 1 serum (0.6%) was negative in 5 kits. On the Mindray kit, IgG antibodies to the antigens of the SARS-CoV-2 virus were detected in 165 samples (99.4%), on Vector-Best – in 164 sera (98.8%), on Diagnostic systems – in 151 (90.96%), on Xema – in 154 (92.8%), and on Abbott – in 155 samples (93.4%). At the same time, 135 (81.33%) samples were positive in all kits, while 30 samples had discordant results (18.07%), and in 9 sera, specific IgG was not detected in 2 or more kits. ROC analysis revealed a high diagnostic value of all tested kits (AUC from 0.908 to 0.998), which indicates a high quality of the separation model of positive and negative samples (p < 0.001). With the cut-off set by the manufacturers, the sensitivity and specificity ranged from 82.8% and 93.3% for the Diagnostic Systems kit to 99.4% and 95.8% for the VectorBest kit. The calculated correlation coefficients were higher between kits with a similar composition of the antigen used in the kits; therefore, it is better to monitor the dynamics of antibodies by diagnostic kits from the same manufacturer.

Download Full-text

EVALUATION OF ELEVEN IMMUNOCHROMATOGRAPHIC ASSAYS FOR SARS-CoV-2 DETECTION: INVESTIGATING DENGUE CROSS-REACTION

10.1101/2020.10.09.20210039 ◽

2020 ◽

Author(s):

Beatriz Araujo Oliveira ◽

Lea Campos de Oliveira ◽

Franciane Mendes de Oliveira ◽

Geovana Maria Pereira ◽

Regina Maia de Souza ◽

...

Keyword(s):

Sensitivity And Specificity ◽

High Sensitivity ◽

Diagnostic Techniques ◽

Cross Reactivity ◽

Cross Reaction ◽

List Type ◽

Rt Pcr ◽

Serum Samples ◽

Igm Antibodies ◽

Good Agreement

AbstractBackgroundCOVID-19 disease (Coronavirus disease 2019) caused by SARS-CoV-2 (Severe acute respiratory syndrome coronavirus 2) is widespread worldwide, affecting more than 11 million people globally (July 6th, 2020). Diagnostic techniques have been studied in order to contain the pandemic. Immunochromatographic (IC) assays are feasible and low cost alternative for monitoring the spread of COVID-19 in the population.MethodsHere we evaluate the sensitivity and specificity of eleven different immunochromatographic tests in 98 serum samples from confirmed cases of COVID-19 through RT-PCR and 100 negative serum samples from blood donors collected in February 2019. Considering the endemic situation of Dengue in Brazil, we also evaluated the cross-reactivity with Dengue using 20 serum samples from patients with confirmed diagnosis for Dengue collected in early 2019 through four different tests.ResultsOur results demonstrated agreement between immunochromatographic assays and RT-PCR, especially after 10 days since the onset of symptoms. The evaluation of IgG and IgM antibodies combined demonstrated a strong level of agreement (0.85) of IC assays and RT-PCR. It was observed cross-reactivity between Dengue and COVID-19 using four different IC assays for COVID-19 diagnosis. The specificity of IC assays to detected COVID-19 IgM antibodies using Dengue serum samples varied from 80% to 85%; the specificity of IgG detection was 100% and total antibody was 95%.ConclusionsWe found high sensitivity, specificity and good agreement of IC assays, especially after 10 days onset of symptoms. However, we detected cross-reactivity between Dengue and COVID-19 mainly with IgM antibodies demonstrating the need for better studies about diagnostic techniques for these diseases.HighlightsImmunochromatographic assays demonstrated high sensitivity and specificity and good agreement with the gold-standard RT-PCR;Increase in sensitivity and specificity of assays using samples collected after the 10th day of symptoms;Cross-reaction with Dengue serology in evaluation of IgM.

Download Full-text

Comparison of Coombs Gel Test with ELISA and Standard Tube Agglutination Tests Used in Serological Diagnosis of Brucellosis

Infectious Diseases and Clinical Microbiology ◽

10.36519/idcm.2019.0024 ◽

2020 ◽

Vol 2 (1) ◽

pp. 1-7 ◽

Cited By ~ 1

Author(s):

Cigdem Akalan Kuyumcu ◽

Serpil Erol ◽

Rıza Adaleti ◽

Seniha Senbayrak ◽

Secil Deniz ◽

...

Keyword(s):

Sensitivity And Specificity ◽

Diagnostic Tests ◽

Serological Test ◽

High Sensitivity ◽

Serological Diagnosis ◽

Control Groups ◽

Serum Samples ◽

Serological Tests ◽

Reliable Test ◽

And Control

Objective: Serological tests are the most commonly used tests in the diagnosis of brucellosis; however, each serological test has some drawbacks. In this study, we aimed to determine the value of the Brucella Coombs gel test (BCGT) in the serological diagnosis of brucellosis in comparison with Standard tube agglutination (STA) and ELISA tests. Materials and Methods: The study included 42 patients who were considered to have brucellosis as a preliminary diagnosis. BCGT, Brucella-IgM/IgG ELISA, and STA tests were performed from serum samples of the patients. The correlation of the diagnostic tests was analyzed using Cohen’s Kappa Analysis. Results: Twenty-seven (64.2%) of 42 patients were diagnosed with brucellosis according to their medical history and clinical and serological tests. The sensitivity and specificity of BCGT to diagnose brucellosis was 96.2%, and 100%, respectively. The sensitivity and specificity for the diagnosis of brucellosis 62.9% and 100% for STA, respectively; 33.3% and 66.6% for Brucella-IgM; and 66.6% and 100% for Brucella-IgG. BCGT was significantly correlated with STA (κ= 0.590) and Brucella-IgG (κ=0.539) Conclusion: BCGT can be utilized as a simple and reliable test in the diagnosis of brucellosis with high sensitivity and specificity. Nevertheless, the sensitivity and specificity of BCGT should be demonstrated by comprehensive studies, including culture-confirmed cases and control groups.

Download Full-text

Serum metabolomics reveals dysregulation and diagnostic potential of oxylipins in tumor-induced osteomalacia

The Journal of Clinical Endocrinology & Metabolism ◽

10.1210/clinem/dgab885 ◽

2021 ◽

Author(s):

Yiyi Gong ◽

Xiaolin Ni ◽

Chenxi Jin ◽

Xiang Li ◽

Yujie Wang ◽

...

Keyword(s):

Sensitivity And Specificity ◽

Fibroblast Growth Factor 23 ◽

Tumor Resection ◽

High Sensitivity ◽

Leukotriene B4 ◽

Arachidonic Acid Metabolism ◽

Serum Samples ◽

Diagnostic Potential ◽

Liquid Chromatography Tandem Mass ◽

Diagnostic Panel

Abstract Context Excessive production of fibroblast growth factor 23 (FGF23) by tumor was considered as the main pathogenesis in tumor-induced osteomalacia (TIO). Despite its importance to comprehensive understanding of pathogenesis and diagnosis, the regulation of systemic metabolism in TIO remains unclear. Objectives We aimed to systematically characterize the metabolome alteration associated with TIO. Methods By means of liquid chromatography-tandem mass spectrometry (LC-MS) based metabolomics, we analyzed the metabolic profile from 96 serum samples (32 initial diagnosis TIO patients, pairwise samples after tumor resection and 32 matched healthy control subjects). In order to screen and evaluate potential biomarkers, statistical analyses, pathway enrichment and receiver operating characteristic (ROC) were performed. Results Metabolomic profiling revealed distinct alterations between TIO and HC cohort. Differential metabolites were screened and conducted to functional clustering and annotation. Significantly enriched pathway was found involved in arachidonic acid metabolism. A combination of 5 oxylipins, 4-HDoHE, leukotriene B4, 5-HETE, 17-HETE and 9,10,13-TriHOME, demonstrated a high sensitivity and specificity panel for TIO prediction screened by random forest (RF) algorithm (AUC=0.951, 95% confidence interval, CI 0.827-1). Supported vector machine (SVM) model and partial least-squares (PLS) model were conducted to validate the predictive capabilities of the diagnostic panel. Conclusions Metabolite profiling of TIO altered significant compared with HC. A high sensitivity and specificity panel with 5 oxylipins were tested as diagnostic predictor. For the first time, we provide the global profile of metabolomes and identify potential diagnostic biomarkers of TIO. The present work may offer novel insights into the pathogenesis of TIO.

Download Full-text

Evaluation of the performance of three serological tests for diagnosis of Leishmania infantum infection in dogs using latent class analysis

Revista Brasileira de Parasitologia Veterinária ◽

10.1590/s1984-29612020105 ◽

2020 ◽

Vol 29 (4) ◽

Author(s):

Asier Basurco ◽

Alda Natale ◽

Katia Capello ◽

Antonio Fernández ◽

María Teresa Verde ◽

...

Keyword(s):

Sensitivity And Specificity ◽

Leishmania Infantum ◽

Latent Class ◽

Rapid Test ◽

Antibody Test ◽

Latent Class Models ◽

Canine Leishmaniasis ◽

Enzyme Linked Immunosorbent Assay ◽

Serum Samples ◽

Serological Tests

Abstract Canine leishmaniasis (CanL) is a disease caused by Leishmania infantum. Serological methods are the most common diagnostic techniques used for the diagnosis of the CanL. The objective of our study was to estimate the sensitivity and specificity of one in-house ELISA kit (ELISA UNIZAR) and three commercially available serological tests (MEGACOR Diagnostik GmbH) including an immunochromatographic rapid test (FASTest LEISH®), an immunofluorescent antibody test (MegaFLUO LEISH®) and an enzyme-linked immunosorbent assay (MegaELISA LEISH®), using latent class models in a Bayesian analysis. Two hundred fifteen serum samples were included. The highest sensitivity was achieved for FASTest LEISH® (99.38%), ELISA UNIZAR (99.37%), MegaFLUO LEISH® (99.36%) followed by MegaELISA LEISH® (98.49%). The best specificity was obtained by FASTest LEISH® (98.43%), followed by ELISA UNIZAR (97.50%), whilst MegaFLUO LEISH® and MegaELISA LEISH® obtained the lower specificity (91.94% and 91.93%, respectively). The results of present study indicate that the immunochromatographic rapid test evaluated FASTest LEISH® show similar levels of sensitivity and specificity to the quantitative commercial tests. Among quantitative serological tests, sensitivity and specificity were similar considering ELISA or IFAT techniques.

Download Full-text

Evaluation of LipL32 ELISA for detection of bovine leptospirosis in West Java

Jurnal Ilmu Ternak dan Veteriner ◽

10.14334/jitv.v22i2.1610 ◽

2018 ◽

Vol 22 (2) ◽

pp. 80

Author(s):

Sumarningsih . ◽

Susanti . ◽

Simson Tarigan

Keyword(s):

Sensitivity And Specificity ◽

Roc Curve ◽

Area Under Curve ◽

Roc Analysis ◽

Rapid Test ◽

Agglutination Test ◽

Dna Encoding ◽

West Java ◽

Coating Antigen ◽

Bovine Leptospirosis

The current diagnosis of leptospirosis, micro Agglutination Test (MAT) and isolation, is expensive, impractical and technically demanding. This study was aimed at developing an ELISA based on recombinant LipL32 as a practical, inexpensive test for Leptospirosis. The DNA encoding LipL32 was isolated from Leptospira pomona, inserted into pRSET-C plasmid then expressed in E.coli BL21 as a poly-histidine-tagged protein. The amount of LipL32 protein, which was purified from the supernatant of lysed cells by a Ni-NTA column, was 1mg/l culture. This purified LipL32 was used as the coating antigen at 5µg/ml. The accuracy of ELISA was evaluated based on ROC analysis, by comparing the ELISA and MAT results of 517 bovine sera. Result in this study showed that the area under curve (AUC) was 0.853, which categorised the LipL32 ELISA as a “moderately accurate” test and indicates that the ELISA was able to differentiate positive and negative Leptospirosis serum. The result also showed ELISA LipL32 could detect serum positive MAT to Hardjo, Grippotyphosa, Tarrasovi, Rachmati and Bataviae. The optimal cut off for OD ELISA determined based on ROC curve was 0.504, and it showed sensitivity and specificity of ELISA LipL32 relative to MAT were 86.0% and 69.5%, respectively. Overall, the result in this study showed that ELISA LipL32 can be used as a rapid test for identification of anti-Leptospira antibodies in bovine.

Download Full-text

Comparison of diagnostics of bacterial vaginosis according to clinical signs with results of laboratory investigations

Journal of obstetrics and women s diseases ◽

10.17816/jowd65476-82 ◽

2016 ◽

Vol 65 (4) ◽

pp. 76-82

Author(s):

Elena V. Shipitsina ◽

Tatyana A. Khusnutdinova ◽

Olga S. Ryzhkova ◽

Anna A. Krysanova ◽

Olga V. Budilovskaya ◽

...

Keyword(s):

Bacterial Vaginosis ◽

Real Time ◽

Sensitivity And Specificity ◽

Real Time Pcr ◽

Vaginal Discharge ◽

Clinical Signs ◽

High Sensitivity ◽

Clinical Diagnostics ◽

Laboratory Diagnostics ◽

Molecular Method

Introduction. Bacterial vaginosis (BV) is associated with a number of reproductive health disorders, therefore timely and accurate diagnosis of this condition is exceedingly important. Objective.Comparison of effectiveness of clinical and laboratory diagnostics of BV in women with vaginal discharge. Material and methods. In total, 318 patients addressing gynecological clinics with complaints about vaginal discharge participated in the study. Clinical diagnostics of BV was performed in the clinics participating in patient enrollment in accordance with their clinical practice. For laboratory diagnostics, microscopy of Gram stained smears according to the Nugent method and quantitative real-time PCR were used. Sensitivity and specificity of clinical diagnostics of BV and the molecular method were evaluated using the Nugent method as reference standard. Results. With the Nugent method, BV was diagnosed in 27% of women, with real-time PCR — in 37% of women. Using clinical signs of BV, the condition was diagnosed in 91% women. Sensitivity and specificity of the real-time PCR were 97% and 87%, respectively. Sensitivity of clinical diagnostics was 100%, but specificity was only 17%. Conclusions. Diagnostics of BV based only on the presence of vaginal discharge leads to false positive results and requires laboratory confirmation. The molecular method has a high sensitivity and satisfactory specificity for BV diagnosis and can be used as an alternative to the Nugent method.

Download Full-text

Sensitivity and specificity of a rapid test for assessment of exposure to SARS-CoV-2 in a community-based setting in Brazil

10.1101/2020.05.06.20093476 ◽

2020 ◽

Cited By ~ 6

Author(s):

Lucia Campos Pellanda ◽

Eliana Márcia da Ros Wendland ◽

Alan John Alexander McBride ◽

Luciana Tovo-Rodrigues ◽

Marcos Roberto Alves Ferreira ◽

...

Keyword(s):

Diagnostic Test ◽

Rapid Diagnostic Test ◽

Sensitivity And Specificity ◽

Rapid Test ◽

Laboratory Diagnosis ◽

Epidemiological Studies ◽

Population Based ◽

Serum Samples ◽

Kappa Score ◽

Qrt Pcr

AbstractBackgroundWhile the recommended laboratory diagnosis of COVID-19 is a molecular based assay, population-based studies to determine the prevalence of COVID-19 usually use serological assays.ObjectiveTo evaluate the sensitivity and specificity of a rapid diagnostic test for COVID-19 compared to quantitative reverse transcription polymerase chain reaction (qRT-PCR).MethodsWe evaluated the sensitivity using a panel of finger prick blood samples from participants >18 years of age that had been tested for COVID-19 by qRT-PCR. For assessing specificity, we used serum samples from the 1982 Pelotas (Brazil) Birth Cohort participants collected in 2012 with no exposure to SARS-CoV-2.ResultsThe sensitivity of the test was 77.1% (95% CI 66.6 - 85.6), based upon 83 subjects who had tested positive for qRT-PCR at least 10 days before the rapid diagnostic test (RDT). Based upon 100 sera samples, specificity was 98.0% (95% CI 92.9 - 99.8). There was substantial agreement (Kappa score 0.76) between the qRT-PCR results and the RDT.InterpretationThe validation results are well in line with previous assessments of the test, and confirm that it is sufficiently precise for epidemiological studies aimed at monitoring levels and trends of the COVID-19 pandemic.

Download Full-text

Evaluation of a Rapid Kit for Detection of IgM against Leptospira in Human

Canadian Journal of Infectious Diseases and Medical Microbiology ◽

10.1155/2019/5763595 ◽

2019 ◽

Vol 2019 ◽

pp. 1-4 ◽

Cited By ~ 1

Author(s):

Mohan Rao ◽

Fairuz Amran ◽

Nadia Aqilla

Keyword(s):

Sensitivity And Specificity ◽

Predictive Value ◽

Clinical Manifestations ◽

Rapid Test ◽

Febrile Illness ◽

High Sensitivity ◽

Confirmatory Test ◽

Standard Laboratory ◽

Test Efficiency ◽

Sensitivity Specificity

Introduction. Leptospirosis is an acute febrile illness, known for its protean clinical manifestations and the challenge in differentiating from other infectious diseases. Standardized confirmatory test is antibody dependent and not accessible by the suburban community. This study measures efficiency of an immune-chromatographic assay, Leptocheck WB, in detecting acute leptospirosis. Methods. A total of 142 sera were used for kit evaluation. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated by comparing rapid kit results with gold standard laboratory, microscopic agglutination test (MAT). Results. We found this rapid kit to have a sensitivity and specificity of 66.6% and 78.9%, respectively, whereas the PPV and NPV of the kit appeared to be 73.3% and 73.2%, respectively. Discussion. Test efficiency of this rapid kit is reasonable. It is specific in detecting leptospiral antibody and assures clinician of accurate diagnosis by having higher PPV and NPV. It is prompt and efficient in comparison with conventional methods in assisting differential diagnosis. High sensitivity and specificity leptospirosis rapid test is indeed a crucial measure to assist the diagnosis of acute undifferentiated febrile illnesses.

Download Full-text