scholarly journals Performance characteristics and costs of serological tests for brucellosis in a pastoralist community of northern Tanzania

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
AbdulHamid S. Lukambagire ◽  
Ângelo J. Mendes ◽  
Rebecca F. Bodenham ◽  
John A. McGiven ◽  
Nestory A. Mkenda ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Standardized Testing ◽  
Predictive Value ◽  
Sub Saharan Africa ◽  
Enzyme Linked Immunosorbent Assay ◽  
Human Brucellosis ◽  
Index Test ◽  
Serological Tests ◽  
Pastoralist Community ◽  
Northern Tanzania

AbstractThe control of brucellosis across sub-Saharan Africa is hampered by the lack of standardized testing and the use of tests with poor performance. This study evaluated the performance and costs of serological assays for human brucellosis in a pastoralist community in northern Tanzania. Serum collected from 218 febrile hospital patients was used to evaluate the performance of seven index tests, selected based on international recommendation or current use. We evaluated the Rose Bengal test (RBT) using two protocols, four commercial agglutination tests and a competitive enzyme-linked immunosorbent assay (cELISA). The sensitivity, specificity, positive predictive value, negative predictive value, Youden’s index, diagnostic accuracy, and per-sample cost of each index test were estimated. The diagnostic accuracy estimates ranged from 95.9 to 97.7% for the RBT, 55.0 to 72.0% for the commercial plate tests, and 89.4% for the cELISA. The per-sample cost range was $0.69–$0.79 for the RBT, $1.03–$1.14 for the commercial plate tests, and $2.51 for the cELISA. The widely used commercial plate tests performed poorly and cost more than the RBT. These findings provide evidence for the public health value of discontinuing the use of commercial agglutination tests for human brucellosis in Tanzania.

scholarly journals The Clinical Utility of the Heparin Neutralization Assay in the Diagnosis of Heparin-Induced Thrombocytopenia

2017 ◽  
Vol 24 (5) ◽  
pp. 749-754 ◽  
Author(s):  
Gang Zheng ◽  
Michael B. Streiff ◽  
Clifford M. Takemoto ◽  
Jennifer Bynum ◽  
Elise Gelwan ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Predictive Value ◽  
Clinical Utility ◽  
Predictive Accuracy ◽  
High Sensitivity ◽  
Neutralization Assay ◽  
Serotonin Release ◽  
Enzyme Linked Immunosorbent Assay ◽  
Heparin Induced Thrombocytopenia ◽  
Heparin Neutralization

Heparin-induced thrombocytopenia (HIT) remains diagnostically challenging. Immunoassays including PF4/heparin enzyme-linked immunosorbent assay (ELISA) have high sensitivity but low specificity. Whether the heparin neutralization assay (HNA) improves the diagnostic accuracy of the PF4/heparin ELISA for HIT is uncertain. In this study, to assess its clinical utility and evaluate whether it improves the diagnostic accuracy for HIT, we implemented HNA in conjunction with PF4/heparin ELISA over a 1-year period. A total of 1194 patient samples were submitted to the laboratory for testing from December 2015 to November 2016. Heparin neutralization assay alone is a poor predictor for HIT, but it has high negative predictive value (NPV): Cases with %inhibition <70% are always negative for serotonin release assay. It improves the diagnostic positive predictive value (PPV) of ELISA without compromising sensitivity: ELISA optical density (OD) ≥1.4 alone has a sensitivity of 88% (14/16) and a PPV of 61% (14/23); with HNA %inhibition ≥70%, the sensitivity remains 88% (14/16) and PPV is 82% (14/17). 4Ts score correlates with ELISA OD and predicts HIT; the predictive accuracy of 4Ts score is further improved by HNA. Interestingly, HNA %inhibition of <70% correlates with low 4Ts scores. Based on its high NPV, HNA has the potential to facilitate more timely and accurate HIT diagnosis.

scholarly journals Diagnostic Accuracy of COVID-19 Antibody Tests Authorized by FDA Philippines: A Systematic Review and Meta-Analysis

2021 ◽  
Vol 3 (4) ◽  
pp. 283-301
Author(s):  
Carmel Reina R. Chua ◽  
Esther Delle E. De los Santos ◽  
Karla Veronica H. Escasa ◽  
Richmond Louis G. Estolas ◽  
Junnealyn Feliciano ◽  
...  
Keyword(s):  
Systematic Review ◽  
Diagnostic Accuracy ◽  
Random Effects ◽  
Meta Analysis ◽  
Characteristic Curve ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serological Tests ◽  
Random Effects Models ◽  
Specificity And Sensitivity ◽  
Antibody Tests

Introduction: Coronavirus Disease (COVID-19) is a highly infectious disease caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) which has infected many people all over the world. One of the best ways to lessen its spread is through early detection and diagnosis. Various serological tests are now being used as a surveillance tool in the detection of antibodies as a response to SARS-CoV-2. The aim of this study is to evaluate the diagnostic accuracy and performance of the available COVID-19 antibody tests authorized by the Food and Drug Administration (FDA) Philippines that make use of Enzyme-Linked Immunosorbent Assay (ELISA), Chemiluminescence Immunoassay (CLIA) and Lateral Flow Immunoassay (LFIA). Method: Complete published journal articles relevant to the diagnostic accuracy of the three antibody tests were collected using trusted medical journal search engines. The quality of journals was assessed using QUADAS-2 to determine the risk of bias and assess the applicability judgments of diagnostic accuracy studies. Forest plots were used to summarize the performance of LFIA, ELISA and CLIA according to their specificity and sensitivity in detecting various antibodies. Pooled sensitivity and specificity were also done using bivariate random-effects models with its log-likelihood, a corresponding chi-square test statistic, and area under the summary Receiver-Operating Characteristic curve to see the potential heterogeneity in the data and to assess the diagnostic accuracy of the COVID-19 antibody tests. Results: Bivariate random-effects model and areas under the sROC curve were used to evaluate the diagnostic accuracy of COVID-19 antibody tests. The pooled sensitivity in detecting IgG based on CLIA, ELISA, and LFIA were 81.7%, 58.7%, and 74.3% respectively, with an overall of 72.0%. For IgM detection, LFIA has a higher pooled sensitivity of 69.6% than CLIA with 61.0%. Overall, the pooled sensitivity is 68.5%. In IgA detection, only ELISA based test was included with a pooled sensitivity of 84.8%. Lastly, pooled sensitivities for combined antibodies based on ELISA and LFIA were 89.0% and 81.6% respectively, with an overall of 82.5%. On the other hand, all tests excluding ELISA-IgA displayed high pooled specificities with a range of 94.0% to 100.0%. Diagnostic accuracies of the test in detecting IgG, IgM, and combined antibodies were found out to be almost perfect based on the computed area under the sROC with values of 0.973, 0.953, and 0.966, respectively. Conclusion: In this systematic review and meta-analysis, existing evidence on the diagnostic accuracy of antibody tests for COVID-19 were found to be characterized by high risks of bias, consistency in the heterogeneity of sensitivities, and consistency in the homogeneity of high specificities except in IgA detection using ELISA. The bivariate random-effects models showed that there are no significant differences in terms of sensitivity among CLIA, ELISA and LFIA in detecting IgG, IgM, and combined antibodies at a 95% confidence interval. Nonetheless, CLIA, ELISA and LFIA were found to have excellent diagnostic accuracies in the detection of IgG, IgM and combined antibodies as reflected by their AUC values. Doi: 10.28991/SciMedJ-2021-0304-1 Full Text: PDF

scholarly journals Complement Component C1q as an Emerging Biomarker for the Diagnosis of Tuberculous Pleural Effusion

2021 ◽  
Vol 12 ◽  
Author(s):  
Xin Qiao ◽  
Ming-Ming Shao ◽  
Feng-Shuang Yi ◽  
Huan-Zhong Shi
Keyword(s):  
Pleural Effusion ◽  
Confidence Interval ◽  
Diagnostic Accuracy ◽  
Predictive Value ◽  
Complement Component ◽  
Enzyme Linked Immunosorbent Assay ◽  
Age And Gender ◽  
Tuberculous Pleural Effusion ◽  
And Gender ◽  
Sensitivity Specificity

Background and Objective: The accurate differential diagnosis of tuberculous pleural effusion (TPE) from other exudative pleural effusions is often challenging. We aimed to validate the accuracy of complement component C1q in pleural fluid (PF) in diagnosing TPE.Methods: The level of C1q protein in the PF from 49 patients with TPE and 61 patients with non-tuberculous pleural effusion (non-TPE) was quantified by enzyme-linked immunosorbent assay, and the diagnostic performance was assessed by receiver operating characteristic (ROC) curves based on the age and gender of the patients.Results: The statistics showed that C1q could accurately diagnose TPE. Regardless of age and gender, with a cutoff of 6,883.9 ng/mL, the area under the curve (AUC), sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of C1q for discriminating TPE were 0.898 (95% confidence interval: 0.825–0.947), 91.8 (80.4–97.7), 80.3 (68.2–89.4), 78.9 (69.2–86.2), and 92.5 (82.6–96.9), respectively. In subgroup analysis, the greatest diagnostic accuracy was achieved in the younger group (≤ 50 years of age) with an AUC of 0.981 (95% confidence interval: 0.899–0.999) at the cutoff of 6,098.0 ng/mL. The sensitivity, specificity, PLR, NLR, PPV, and NPV of C1q were 95.0 (83.1–99.4), 92.3 (64.0–99.8), 97.4 (85.2–99.6), and 85.7 (60.6–95.9), respectively.Conclusion: Complement component C1q protein was validated by this study to be a promising biomarker for diagnosing TPE with high diagnostic accuracy, especially among younger patients.

scholarly journals Protocol for a diagnostic accuracy study to develop diagnosis algorithm for biliary atresia using MMP-7 (DIABA-7 study): a study recruiting from Chinese Biliary Atresia Collaborative Network

BMJ Open ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. e052328
Author(s):  
Jingying Jiang ◽  
Jiale Deng ◽  
Gong Chen ◽  
Rui Dong ◽  
Song Sun ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Biliary Atresia ◽  
Predictive Value ◽  
Pearson Correlation ◽  
Collaborative Network ◽  
Index Test ◽  
Operating Characteristics ◽  
Serum Samples ◽  
Study Results ◽  
Diagnosis Algorithm

IntroductionBiliary atresia is a severe liver disease in neonates, and the prognosis partially depends on the age at which infants undergo the Kasai procedure. Matrix metalloproteinase-7 (MMP-7) was confirmed to have significant value in the diagnosis of biliary atresia. However, so far, the reference range and its cut-off value for diagnosing biliary atresia have not been established yet.Methods and analysisDIagnosis Algorithm for Biliary Atresia (DIABA-7) is a prospective diagnostic test. Cholestatic infants and normal controls within 150 days of age are recruiting from the Chinese Biliary Atresia Collaborative Network. The serum samples and dried blood spot (DBS) samples are obtained to detect MMP-7 concentrations using an ELISA kit. The reference standard is the intraoperative exploration and subsequent histological examination of liver biopsies. Lambda-Mu-Sigma (LMS) method is used to calculate the normal range of serum MMP-7 of each age group. Receiver operating characteristics (ROC) curves are constructed to calculate the best cut-off point and area under the curve for the index test. The sensitivity, specificity, positive predictive value and negative predictive value are used to show the diagnostic accuracy. Pearson correlation coefficient test is applied to assess the correlation of serum MMP-7 and DBS MMP-7.Ethics and disseminationThis study was reviewed and approved by the Ethics Committee of Children’s Hospital of Fudan University (Number 2020–296). Dissemination will be guided by investigators and patients. The aim is to publish the study results in a high-quality peer-reviewed journal and present the findings at international academic meetings.Trial registration numberChiCTR2000032983.

scholarly journals DIAGNOSTIC ACCURACY OF DRUG SCREENING IMMUNOASSAYS IN DRUG FACILITATED CRIMES

2021 ◽  
Vol 71 (1) ◽  
pp. 101-06
Author(s):  
Sadia Dawood ◽  
Ayesha Hafeez ◽  
Aamir Ijaz ◽  
Summera Moeen ◽  
Asif Ali Memon ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Diagnostic Accuracy ◽  
Drug Screening ◽  
Public Transportation ◽  
Predictive Value ◽  
False Negative ◽  
False Negative Rate ◽  
Armed Forces ◽  
Index Test

Objective: To determine the diagnostic accuracy of immunoassays in drug screening as required in emergency for the rapid diagnosis of drug intoxication in travel related crimes. Study Design: Diagnostic accuracy study. Place and Duration of Study: department of Chemical Pathology and Endocrinology, Armed Forces Institute ofPathology, Rawalpindi Pakistan, from Jul 2017 to Jun 2018. Methodology: Sealed urine specimens of 77 patients with history of suspected intoxication in drugs facilitatedstreet crimes, received for toxicology screening were included in the study. All the specimens were analysed,initially on immunoassay (index test) and then on Triple Quadrupole Liquid chromatography–Mass spectrometry (reference standard). Benzodiazepine being the main class of drugs involved in travel related crimes, diagnostic accuracy of immunoassay technique was assessed for these by calculating its sensitivity, specificity, positive predictive value and negative predictive value. Results: Victims were predominantly males and public transportation was the most common mode of transport. The most commonly used drug was Lorazepam. Immunoassay failed to detect few cases who were shown to be intoxicated with benzodiazepines by liquid-chromatography tandem mass spectrometry. The false negative rate was 4.9%. Only one false positive case was observed. The accuracy was calculated to be 94.8% with sensitivity of 95.08% and specificity of 93.7%. Conclusion: Immunoassay was found reliable for rapid testing in drug facilitated intoxication cases. Howevercritical decision making should be done cautiously keeping in mind the limitations associated with thesescreening procedures.

scholarly journals Seroprevalence of brucellosis in patients with prolonged fever in Bangladesh

2016 ◽  
Vol 10 (09) ◽  
pp. 939-946 ◽  
Author(s):  
AKM Anisur Rahman ◽  
Dirk Berkvens ◽  
Claude Saegerman ◽  
David Fretin ◽  
Noor Muhammad ◽  
...  
Keyword(s):  
Agglutination Test ◽  
Enzyme Linked Immunosorbent Assay ◽  
Human Brucellosis ◽  
Chain Reaction ◽  
Serological Tests ◽  
Human Sera ◽  
Polymerase Chain ◽  
Species Specific ◽  
First Time ◽  
Sera Samples

Introduction: This study describes the seroprevalence of human brucellosis among pyretic patients and detection of Brucella abortus DNA from seropositive pyretic patients using real-time polymerase chain reaction (rtPCR) for the first time in Bangladesh. Methodology: Blood samples were collected from 300 pyretic patients from October 2007 to May 2008 and subjected to three serological tests: Rose-Bengal plate test (RBT), standard tube agglutination test (STAT), and indirect enzyme-linked immunosorbent assay (iELISA). Risk factors were identified by multivariate Firth’s logistic regression analysis. Brucella genus (BCSP31) and species-specific (IS711) rtPCR were applied to six human sera samples. Results: The seroprevalence of brucellosis among pyretic patients was estimated to be 2.0% (95% confidence interval [CI]: 0.74–4.30). The odds of brucellosis seropositivity were 8.9 (95% CI: 1.26–63.0) times higher in pyretic patients who handled goats than those who handled only cattle, whereas the odds of brucellosis seropositivity were 9.7 (95% CI: 1.28–73.68) times higher in pyretic patients who had backache compared to those without backache. B. abortus DNA was amplified from all six human sera that tested positive by RBT, STAT, and iELISA. As the agreement between the tests was very strong, RBT is recommended as a screening test for the diagnosis of human brucellosis in Bangladesh because it is easier to use, cheaper, and faster. Conclusions: Brucellosis among pyretic patients is common, and B. abortus is responsible for brucellosis in such patients. Pyretic patients who handle goats and those with backaches should be screened for brucellosis.

Abstract 1122‐000033: Automated Detection of Intracerebral Hemorrhage Using Artificial Intelligence: Pilot Deployment of Viz ICH

2021 ◽  
Vol 1 (S1) ◽  
Author(s):  
Roshini Kalagara ◽  
Susmita Chennareddy ◽  
Stavros Matsoukas ◽  
Emma Reford ◽  
Colton Smith ◽  
...  
Keyword(s):  
Artificial Intelligence ◽  
Intracerebral Hemorrhage ◽  
Diagnostic Accuracy ◽  
Likelihood Ratio ◽  
Predictive Value ◽  
Positive Likelihood Ratio ◽  
Negative Likelihood Ratio ◽  
Index Test ◽  
Scan Time ◽  
Initial Care

Introduction : Stroke is a major cause of morbidity and mortality. Hemorrhagic strokes are often more severe and associated with higher mortality when compared to ischemic stroke and account for approximately 13% of all strokes. Initial care for patients with intracerebral hemorrhage (ICH) is in part guided by neuroimaging findings. Non‐contrast computed tomography (NCCT) is often the first imaging obtained in the work up of the acute stroke patient given its diagnostic accuracy for hemorrhage, ubiquity, low cost, and short scan time. Immediate evaluation of imaging by stroke experts, such as neurologists, neurosurgeons, and radiologists, is essential. Artificial intelligence tools can help to expedite image assessment and careteam coordination thereby accelerating time to treatment. In this study, we report on the use of Viz ICH, an AI‐enhanced ICH detection platform, to identify ICH on initial CT and coordinate emergent care in an urban health system with an ICH Center. Methods : All consecutive stroke codes presenting with ICH from May 2019 to August 2019 were eligible for analysis. Non‐contrast CT (NCCT) was conducted for each patient and submitted to the Viz ICH in a prospective fashion. An automated volumetric analysis of these NCCTs was conducted by Viz ICH and assessment was conducted for potential ICH. If suspected ICH was detected, Viz ICH sent an automated prompt to the stroke care team for review. CT impressions provided by radiologists served as the clinical reference standard test and Viz ICH output served as the index test. Diagnostic accuracy tests were then performed. Results : A total of 682 patients were analyzed for ICH, out of which 28 patients were positive for intracerebral hemorrhage (ICH) (4%) and 654 were negative for hemorrhage (96%) based on radiology impressions. Viz ICH was able to correctly identify hemorrhages in 25/28 patients and non‐hemorrhages in 650/654 patients. Overall, the software had high diagnostic accuracy with 89.3% sensitivity, 99.4% specificity, and an overall accuracy of 99.0%. The software also had a positive predictive value of 86.2%, a negative predictive value of 99.5%, a positive likelihood ratio of 145.98, and a negative likelihood ratio of 0.108. Conclusions : Viz ICH is an AI‐enhanced platform that may help in the diagnosis and detection of ICH, with a sensitivity of 89.3 and a specificity of 99.4% in this preliminary study. Though future validation studies with a larger cohort of patients positive for each type of hemorrhage must be conducted for true diagnostic accuracy data, Viz ICH has the potential to be an adjunct tool to streamline ICH triage, reduce treatment delays, and improve outcomes of patients presenting with ICH.

Rapid Review: Diagnostic Accuracy of Pooled Testing versus Individual Testing Using RT-PCR for SARS-CoV-2 for Screening and Surveillance of Individuals with Suspected COVID-19

2021 ◽  
Author(s):  
Rowena Natividad F. Genuino ◽  
Beatrice J. Tiangco ◽  
John Jefferson V. Besa ◽  
Howell Henrian G. Bayona
Keyword(s):  
Positive Predictive Value ◽  
Diagnostic Accuracy ◽  
Subgroup Analysis ◽  
Predictive Value ◽  
Pool Size ◽  
Rapid Review ◽  
Index Test ◽  
Rt Pcr ◽  
Pooled Testing ◽  
Screening And Surveillance

Background. Pooled testing has been implemented on a limited scale, mainly for screening and surveillance in populations with a low prevalence of COVID-19 to save on limited resources. Objective. To determine the diagnostic accuracy of pooled compared with individual RT-PCR testing for SARS-CoV-2 in individuals suspected of COVID-19. Methods. We searched websites of living CPGs on COVID-19 (Australian COVID-19, COVID NMA, CEBM Oxford), Philippine DOH HTA, databases (PubMed, CENTRAL, medRXIV/bioRXIV), and Clinicaltrials.gov for studies that used pooled testing on individuals suspected of COVID-19. When appropriate, we pooled data for sensitivity and specificity and obtained the range and median of other data, such as positive predictive value and resource savings. We did a priori subgroup analysis for pool size, presence or absence of symptoms and use case, type of specimen, cutoff for positivity, type of kit, and post hoc subgroup analysis for method of pooling and timing of processing. Results. We included 21 studies: 6 diagnostic accuracy studies, and 15 clinical validation studies. Studies had varying populations, index test kit and performance characteristics, positivity rate (0.02 to 15%), and pool size (5 to 16). There was moderate pooled sensitivity, 81% (95% CI 72, 88; I2=73.6%; 6 studies, 776 pools) and high pooled specificity, 99% (95% CI, 98 to 100; I2=1.84%; 5 studies, 666 pools). Positive predictive value based on 21 studies ranged from 67% to 100%. Resource savings in the number of test kits used ranged from 49 to 89%. Identified harms of pooled testing were delayed turnaround time for positive samples and laboratory errors. Conclusion. There is moderate sensitivity and high specificity with pooled testing for the screening of individuals with suspected COVID-19. We recommend further studies to validate the utility based on community prevalence and other test variables.

scholarly journals Diagnostic accuracy of non-contact infrared thermometers and thermal scanners: a systematic review and meta-analysis

2020 ◽  
Vol 27 (8) ◽  
Author(s):  
Nishant Aggarwal ◽  
Mohil Garg ◽  
Vignesh Dwarakanathan ◽  
Nitesh Gautam ◽  
Swasthi S Kumar ◽  
...  
Keyword(s):  
Systematic Review ◽  
Diagnostic Accuracy ◽  
Predictive Value ◽  
Meta Analysis ◽  
World Health ◽  
Cochrane Library ◽  
Research Database ◽  
Index Test ◽  
Reference Standard ◽  
Operating Characteristics

Abstract Infrared thermal screening, via the use of handheld non-contact infrared thermometers (NCITs) and thermal scanners, has been widely implemented all over the world. We performed a systematic review and meta-analysis to investigate its diagnostic accuracy for the detection of fever. We searched PubMed, Embase, the Cochrane Library, medRxiv, bioRxiv, ClinicalTrials.gov, COVID-19 Open Research Dataset, COVID-19 research database, Epistemonikos, EPPI-Centre, World Health Organization International Clinical Trials Registry Platform, Scopus and Web of Science databases for studies where a non-contact infrared device was used to detect fever against a reference standard of conventional thermometers. Forest plots and Hierarchical Summary Receiver Operating Characteristics curves were used to describe the pooled summary estimates of sensitivity, specificity and diagnostic odds ratio. From a total of 1063 results, 30 studies were included in the qualitative synthesis, of which 19 were included in the meta-analysis. The pooled sensitivity and specificity were 0.808 (95%CI 0.656–0.903) and 0.920 (95%CI 0.769–0.975), respectively, for the NCITs (using forehead as the site of measurement), and 0.818 (95%CI 0.758–0.866) and 0.923 (95%CI 0.823–0.969), respectively, for thermal scanners. The sensitivity of NCITs increased on use of rectal temperature as the reference. The sensitivity of thermal scanners decreased in a disease outbreak/pandemic setting. Changes approaching statistical significance were also observed on the exclusion of neonates from the analysis. Thermal screening had a low positive predictive value, especially at the initial stage of an outbreak, whereas the negative predictive value (NPV) continued to be high even at later stages. Thermal screening has reasonable diagnostic accuracy in the detection of fever, although it may vary with changes in subject characteristics, setting, index test and the reference standard used. Thermal screening has a good NPV even during a pandemic. The policymakers must take into consideration the factors surrounding the screening strategy while forming ad-hoc guidelines.

scholarly journals B-Cell-Specific Peptides of Leptospira interrogans LigA for Diagnosis of Patients with Acute Leptospirosis

2014 ◽  
Vol 21 (3) ◽  
pp. 354-359 ◽  
Author(s):  
Murugesan Kanagavel ◽  
Santhanam Shanmughapriya ◽  
Kumarasamy Anbarasu ◽  
Kalimuthusamy Natarajaseenivasan
Keyword(s):  
Early Diagnosis ◽  
B Cell ◽  
Predictive Value ◽  
Acute Stage ◽  
Antibody Detection ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Serological Tests ◽  
Content Type

ABSTRACTLeptospirosis is a reemerging infectious disease that is underdiagnosed and under-recognized due to low-sensitivity and cumbersome serological tests. Rapid reliable alternative tests are needed for early diagnosis of the disease. Considering the importance of the pathogenesis-associated leptospiral LigA protein expressedin vivo, we have evaluated its application in the diagnosis of the acute form of leptospirosis. The C-terminal coding sequence ofligA(ligA-C) was cloned into pET15b and expressed inEscherichia coli. Furthermore, the B-cell-specific epitopes were predicted and were synthesized as peptides for evaluation along with recombinant LigA-C. Epitope 1 (VVIENTPGK), with a VaxiJen score of 1.3782, and epitope 2 (TALSVGSSK), with a score of 1.2767, were utilized. A total of 140 serum samples collected from leptospirosis cases during the acute stage of the disease and 138 serum samples collected from normal healthy controls were utilized for evaluation. The sensitivity, specificity, positive predictive value, and negative predictive value were calculated for the recombinant LigA-C-specific IgM enzyme-linked immunosorbent assay (ELISA) and were found to be 92.1%, 97.7%, 92.8%, and 97.5%, respectively. Epitopes 1 and 2 used in the study showed 5.1 to 5.8% increased sensitivity over recombinant LigA-C in single and combination assays for IgM antibody detection. These findings suggest that these peptides may be potential candidates for the early diagnosis of leptospirosis.

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