scholarly journals Performance verification of the Abbott SARS-CoV-2 test for qualitative detection of IgG in Cali, Colombia

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0256566
Author(s):  
Maria del Mar Castro ◽  
Isabella Caicedo ◽  
Helen Johanna Ortiz-Rojas ◽  
Carmen Manuela Castillo ◽  
Adriana Giovanna Medina ◽  
...  
Keyword(s):  
High Sensitivity ◽  
High Specificity ◽  
Epidemiologic Studies ◽  
Kappa Index ◽  
Antibody Testing ◽  
Infection Age ◽  
Qualitative Detection ◽  
Variable Sensitivity ◽  
Patient Groups ◽  
Sensitivity Specificity

Background Adequate testing is critically important for control of the SARS-CoV-2 pandemic. Antibody testing is an option for case management and epidemiologic studies, with high specificity and variable sensitivity. However, characteristics of local populations may affect performance of these tests. For this reason, the National Institute of Health (INS) and regulatory agencies in Colombia require verification of diagnostic accuracy of tests introduced to the Colombian market. Methods We conducted a validation study of the Abbott SARS-CoV-2 test for qualitative detection of IgG using the Abbott Architect i2000SR. Participants and retrospective samples were included from patients with suspected SARS-CoV-2 infection, age ≥18 years, and ≥8 days elapsed since initiation of symptoms. Pre-pandemic plasma samples (taken before October 2019) were used as controls. We estimated the sensitivity, specificity and agreement (kappa) of the Abbott IgG test compared to the gold standard (RT-PCR). Results The overall sensitivity was 83.1% (95% CI: 75.4–100). Sensitivity among patients with ≥14 days since the start of symptoms was 85.7%, reaching 88% in samples collected from patients with COVID-19 symptoms onset >60 days. Specificity was 100% and the kappa index of agreement was 0.804 (95% CI: 0.642–0.965). Conclusions Our findings show high sensitivity and specificity of the Abbott IgG test in a Colombian population, which meet the criteria set by the Colombian INS to aid in the diagnosis of COVID-19. Data from our patient groups also suggest that IgG response is detectable in a high proportion of individuals (88.1%) during the first two months following onset of symptoms.

scholarly journals INDIRECT ELISA FOR DETECTION OF ANTIBODIES TO FMDV NON-STRUCTURAL PROTEINS IN PORCINE SERA

2018 ◽  
pp. 13-20
Author(s):  
A. S. Yakovleva ◽  
A. V. Kanshina ◽  
A. V. Scherbakov
Keyword(s):  
Indirect Elisa ◽  
High Sensitivity ◽  
High Specificity ◽  
Structural Proteins ◽  
Post Inoculation ◽  
Nonstructural Proteins ◽  
Diagnostic Specificity ◽  
Fmd Virus ◽  
Specificity And Sensitivity ◽  
Sensitivity Specificity

An indirect variant of ELISA used for detection of antibodies to nonstructural proteins of the FMD virus in porcine blood sera was developed. The results of the validation showed that the developed method is characterized by high sensitivity, specificity and reproducibility. When testing the blood serum panel obtained from experimentally infected animals, the method allowed to detect antibodies to FMD virus in 7 of 18 sera collected on day 6 post inoculation, in 13 of 19 sera – on day 7 post inoculation, in 16 of 19 sera – on day 8 post inoculation and in all 76 sera obtained on days 9–12 post inoculation. The diagnostic specificity of 3AB-ELISA was 100% when testing 100 knowingly negative blood sera from pigs imported to Russia from Norway. High specificity and sensitivity of the method, established during the development of the method, are confirmed in the course of routine diagnostic tests.

scholarly journals COVID Seroprevalence, Symptoms and Mortality During the First Wave of SARS-CoV-2 in Canada

2021 ◽  
Author(s):  
◽  
Prabhat Jha
Keyword(s):  
Nursing Home ◽  
Nursing Homes ◽  
Nursing Home Residents ◽  
High Sensitivity ◽  
High Specificity ◽  
The Elderly ◽  
Dried Blood Spots ◽  
Mortality Data ◽  
Infection Prevalence ◽  
Antibody Testing

Background: Efforts to stem the SARS-CoV-2 pandemic in Canada can benefit from direct understanding of the prevalence, infection fatality rates (IFRs), and information on asymptomatic infection. Methods: We surveyed a representative sample of 19,994 adult Canadians about COVID symptoms and analyzed IgG antibodies against SARS-CoV-2 from self-collected dried blood spots (DBS) in 8,967 adults. A sensitive and specific chemiluminescence ELISA detected IgG to the spike trimer. We compared seroprevalence to deaths to establish IFRs and used mortality data to estimate infection levels in nursing home residents. Results: The best estimate (high specificity) of adult seroprevalence nationally is 1.7%, but as high as 3.5% (high sensitivity) depending on assay cut-offs. The highest prevalence was in Ontario (2.4-3.9%) and in younger adults aged 18-39 years (2.5-4.4%). Based on mortality, we estimated 13-17% of nursing home residents became infected. The first viral wave infected 0.54-1.08 million adult Canadians, half of whom were <40 years old. The IFR outside nursing homes was 0.20-0.40%, but the COVID mortality rate in nursing home residents was >70 times higher than that in comparably-aged adults living in the community. Seropositivity correlated with COVID symptoms, particularly during March. Asymptomatic adults constituted about a quarter of definite seropositives, with a greater proportion in the elderly. Interpretation: Canada had relatively low infection prevalence and low IFRs in the community, but not in nursing homes, during the first viral wave. Self-collected DBS for antibody testing is a practicable strategy to monitor the ongoing second viral wave and, eventually, vaccine-induced immunity among Canadian adults.

scholarly journals High diagnostic accuracy of automated rapid Strep A test reduces antibiotic prescriptions for children in the United Arab Emirates

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Salama Bin Hendi ◽  
Zainab A. Malik ◽  
Amar Hassan Khamis ◽  
Fadil Y. A. Al-Najjar
Keyword(s):  
Diagnostic Accuracy ◽  
United Arab Emirates ◽  
Predictive Value ◽  
High Sensitivity ◽  
Signs And Symptoms ◽  
Throat Culture ◽  
Clinical Criteria ◽  
Variable Sensitivity ◽  
High Level ◽  
Sensitivity Specificity

Abstract Background Diagnosis of Group A Streptococcus (GAS) pharyngitis in children is hindered by variable sensitivity of clinical criteria and rapid Strep A tests (SAT), resulting in reliance on throat cultures as the gold standard for diagnosis. Delays while awaiting culture reports result in unnecessary antibiotic prescriptions among children, contributing to the spread of antimicrobial resistance (AMR). Methods Diagnostic accuracy study of an automated SAT (A-SAT) in children up to 16 years of age presenting to an emergency room with signs and symptoms of pharyngitis between March and June 2019. Paired throat swabs for A-SAT and culture were collected. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for A-SAT were calculated. Results Two hundred and ninety-one children were included in this study. 168 (57.7%) were boys and the mean age was 4.2 years. A-SAT was positive in 94 (32.3%) and throat culture was positive in 90 (30.9%) children. A-SAT and throat culture results showed a high level of consistency in our cohort. Only 6 (2%) children had inconsistent results, demonstrating that the A-SAT has a high sensitivity (98.9%), specificity (97.5%), PPV (94.7%) and NPV (99.5%) for the diagnosis of GAS pharyngitis in children. Only 92 (32%) children were prescribed antibiotics while the vast majority (68%) were not. Conclusions A-SAT is a quick and reliable test with diagnostic accuracy comparable to throat culture. Its widespread clinical use can help limit antibiotic prescriptions to children presenting with pharyngitis, thus limiting the spread of AMR.

scholarly journals Reliability of Cobas Amplicor PCR test in detection of Mycobacterium tuberculosis in respiratory and nonorespiratory specimens

2009 ◽  
Vol 66 (12) ◽  
pp. 992-997
Author(s):  
Zorica Lepsanovic ◽  
Dejana Savic ◽  
Branka Tomanovic
Keyword(s):  
Mycobacterium Tuberculosis ◽  
High Sensitivity ◽  
High Specificity ◽  
Diagnostic Methods ◽  
Nucleic Acid Amplification ◽  
Culture Methods ◽  
Predictive Values ◽  
Polymerase Chain ◽  
Low Sensitivity ◽  
Sensitivity Specificity

Background/Aim. Traditional methods for detection of mycobacteria, such as microscopic examination for the presence of acid-fast bacilli and isolation of the organism by culture, have either a low sensitivity and/or specificity, or take weeks before a definite result is available. Molecular methods, especially those based on nucleic acid amplification, are rapid diagnostic methods which combine high sensitivity and high specificity. The aim of this study was to determine the usefulness of the Cobas Amplicor Mycobacterium tuberculosis polymerase chain reaction (CAPCR) assay in detecting the tuberculosis cause in respiratory and nonrespiratory specimens (compared to culture). Methods. Specimens were decontaminated by the N-acetyl-L-cystein- NaOH method. A 500 ?L aliquot of the processed specimen were used for inoculation of L?wenstein-Jensen (L-J) slants, a drop for acid-fast staining, and 100 ?L for PCR. The Cobas Amplicor PCR was performed according to the manufacturer's instructions. Results. A total of 110 respiratory and 355 nonrespiratory specimens were investigated. After resolving discrepancies by reviewing medical history, overall sensitivity, specificity, and positive and negative predictive values for CA-PCR assay compared to culture, were 83%, 100%, 100%, and 96.8%, respectively. In comparison, they were 50%, 99.7%, 87.5%, and 98%, respectively, for the nonrespiratory specimens. The inhibition rate was 2.8% for respiratory, and 7.6% for nonrespiratory specimens. Conclusion. CA-PCR is a reliable assay that enables specialists to start treatment promptly on a positive test result. Lower value for specificity in a group of nonrespiratory specimens is a consequence of an extremely small number of mycobacteria in some of them.

scholarly journals Dynamics of HEV Antibodies and Development of a Multi-factorial Model to Improve the Diagnosis of Current HEV Infection in Resource-limited Settings

2020 ◽  
Author(s):  
Jie Lu ◽  
Yan Huang ◽  
Peiyun Wang ◽  
Qing Li ◽  
Ziqiang Li ◽  
...  
Keyword(s):  
Detection Efficiency ◽  
High Sensitivity ◽  
High Specificity ◽  
Hepatitis E ◽  
Operating Characteristics ◽  
Serum Samples ◽  
Factorial Model ◽  
Sequential Samples ◽  
Sensitivity Specificity ◽  
Very High

Serological markers are important for the diagnosis of hepatitis E virus (HEV) infection. This study aims to compare the diagnostic performance of the anti-HEV IgM and the HEV Antigen (Ag) assays, and establish a multi-factorial model to improve the diagnosis of current HEV infection when HEV RNA detection is not available. A total of 809 serum samples, including 325 anti-HEV IgM-positive and 484 anti-HEV IgM-negative samples, were tested for HEV RNA. The anti-HEV IgM assay had very high sensitivity (99.4%), but moderate accuracy (79.2%) and specificity (74.3%). By retrospective follow-up of 58 patients with sequential samples (n=143) tested for anti-HEV antibodies, we found anti-HEV IgM remained positive for more than 10 months in some HEV-infected patients, when HEV RNA was already undetectable; thus, decision solely based on anti-HEV IgM may lead to misdiagnosis. In contrast, the HEV Ag assay had very high specificity (100%). However, the detection efficiency of HEV Ag greatly diminished when the HEV RNA level was low or the anti-HEV IgG level was high. By logistic regression, a model integrating anti-HEV IgM, alanine aminotransferase and HEV Ag was proposed and the cut-off value was determined based on the testing results of the 143 sequential samples. The model was further evaluated with 67 randomly-selected IgM-positive samples from single-visit patients. Overall, the model outperformed the anti-HEV IgM or the HEV Ag assay in the diagnosis of current HEV infection (sensitivity/specificity/accuracy: 89.5%/95.2%/91.9%). The area under the receiver operating characteristics curve of the model was greater than 0.97.

Study on Diagnostic Values of Astrocyte Elevated Gene 1 (AEG-1) and Glypican 3 (GPC-3) in Hepatocellular Carcinoma

2019 ◽  
Vol 152 (5) ◽  
pp. 647-655 ◽  
Author(s):  
Wenqing Cao ◽  
Meenal Sharma ◽  
Rami Imam ◽  
Jiangzhou Yu
Keyword(s):  
Hepatocellular Carcinoma ◽  
High Sensitivity ◽  
High Specificity ◽  
The Other ◽  
Diagnostic Potential ◽  
Dysplastic Nodules ◽  
Nontumor Tissue ◽  
Diagnostic Values ◽  
Low Sensitivity ◽  
Sensitivity Specificity

Abstract Objectives To investigate the diagnostic potential of AEG-1 and GPC-3 in hepatocellular carcinoma (HCC). Methods AEG-1 and GPC-3 immunohistochemistry were performed on HCC, adjacent nontumor tissue (ANT), and dysplastic nodules (DN). Results H score of AEG-1 or GPC-3 in HCC was significantly higher than in ANT or DN. In HCC, 92% and 54% showed AEG-1 and GPC-3 positivity, respectively. In ANT, 16.2% were AEG-1 and 7.6% GPC-3 positive. AEG-1 staining was mostly diffuse, whereas GPC-3 frequently showed focal staining. AEG-1 alone showed high sensitivity but low specificity and accuracy. GPC-3, on the other hand, showed high specificity but low sensitivity and accuracy. Combination of both stains boosted the sensitivity, specificity, and accuracy to 94.6%, 89.5%, and 90.5%, respectively, when only diffuse staining was considered as positive. Conclusions AEG-1 or GPC-3 alone seemed not an ideal marker for HCC. The combination of AEG-1 and GPC-3 might improve early diagnosis of HCC.

scholarly journals A Comparative Analysis of Diffusion-weighted Imaging and Ultrasound in Thyroid Nodules

2019 ◽  
Author(s):  
Weidan Kong ◽  
Xiuhui Yue ◽  
Jiliang Ren ◽  
xiaofeng tao
Keyword(s):  
Signal Intensity ◽  
Diffusion Weighted Imaging ◽  
Thyroid Nodules ◽  
Area Under The Curve ◽  
High Sensitivity ◽  
High Specificity ◽  
Adc Value ◽  
Diffusion Weighted ◽  
Significant Difference ◽  
Sensitivity Specificity

Abstract Background: Diffusion-weighted imaging (DWI) and ultrasound are commonly used methods to examine thyroid nodules, but their comparative value is rarely studied. We evaluated the utility of DWI and ultrasound in differentiating benign and malignant thyroid nodules. Methods: A total of 100 patients with 137 nodules who underwent both DWI and ultrasound before operation were enrolled. The T1 and T2 signal intensity ratio (SIR) of each thyroid nodule was calculated by measuring the mean signal intensity divided by that of paraspinal muscle. The apparent diffusion coefficient (ADC) value and the SIR of benign and malignant thyroid nodules were analyzed by two-sample independent t tests. The sensitivity, specificity, and accuracy of DWI and ultrasound were compared with chi-square tests. Results: There was no significant difference in the SIR between benign and malignant thyroid nodules. The ADC value was significantly different. At the threshold value was 1.12 × 10 -3 mm 2 /s, the maximum area under the curve was 0.944. The sensitivity, specificity, and accuracy were 84.9%, 92.2%, and 87.6% respectively. The corresponding values of ultrasound diagnosis were 90.1%, 80.4%, and 86.9%. Conclusions: Ultrasound has high sensitivity in differentiating benign and malignant thyroid nodules, and the ADC value has high specificity, but there is no statistical difference in sensitivity or specificity between the two modalities. DWI and ultrasound each have their own advantages in differentiating benign and malignant thyroid nodules. Keywords Thyroid nodules, Ultrasound, Diffusion-weighted imaging

scholarly journals Chest CT accuracy in the diagnosis of SARS-CoV-2 infection: initial experience in a cancer center

2020 ◽  
Vol 53 (4) ◽  
pp. 211-215 ◽  
Author(s):  
Paula Nicole Vieira Pinto Barbosa ◽  
Almir Galvão Vieira Bitencourt ◽  
Gabriel Diaz de Miranda ◽  
Maria Fernanda Arruda Almeida ◽  
Rubens Chojniak
Keyword(s):  
High Sensitivity ◽  
High Specificity ◽  
Chest Ct ◽  
Cancer Center ◽  
Rt Pcr ◽  
Interpretation Criteria ◽  
Single Center Study ◽  
Constrained Environments ◽  
Diagnosis Of Cancer ◽  
Sensitivity Specificity

Abstract Objective: To evaluate the accuracy of chest computed tomography (CT) in patients with suspected severe acute respiratory syndrome-related coronavirus-2 (SARS-CoV-2) infection at a cancer center. Materials and Methods: This retrospective single-center study selected 91 patients who had chest CT and real-time polymerase chain reaction (RT-PCR) test collected at the same day. CT results were classified in negative, typical, indeterminate or atypical findings. Diagnostic accuracy, sensitivity and specificity were calculated for two different scenarios: in the first, only typical findings on CT were considered positive; in the second, both typical and indeterminate findings were considered positive. Results: Mean patients’ age was 58.2 years, most were male (60.4%) and had prior diagnosis of cancer (85.7%). CT showed typical findings in 28.6%, indeterminate findings in 24.2% and atypical findings in 26.4%. RT-PCR results were positive for SARS-CoV-2 in 27.5%. The sensitivity, specificity and accuracy in the first and second scenarios were respectively 64.0%, 84.8% and 79.1%, and 92.0%, 62.1% and 70.3%. Conclusion: CT has a high accuracy for the diagnosis of SARS-CoV-2 infection. Different interpretation criteria can provide either high sensitivity or high specificity. CT should be integrated as a triage test in resource-constrained environments during the pandemic to assist in the optimization of PCR-tests, isolation beds and intensive care units.

scholarly journals Role of ultrasound, Color duplex Doppler and sono-elastography in the evaluation of renal allograft complications

2019 ◽  
Vol 50 (1) ◽  
Author(s):  
Abeer Mohammed Abd El-Motaal ◽  
Rasha M. Dawoud ◽  
Mohamed F. Sherif ◽  
Tarek A. Eldiasty
Keyword(s):  
Renal Transplantation ◽  
Renal Allograft ◽  
Color Doppler ◽  
Prognostic Index ◽  
High Sensitivity ◽  
High Specificity ◽  
Imaging Method ◽  
Duplex Doppler ◽  
Stage Renal Disease ◽  
Sensitivity Specificity

Abstract Background Renal transplantation could be considered for patients with end-stage renal disease. Ultrasonography is the imaging method chosen for renal allograft evaluation early in the postoperative period. Sono-elastography is used to estimate tissue stiffness. This study aimed to assess the correlation between sono-elastography and renal allograft histopathology in patients who had transplanted kidney and determine the efficacy of grayscale ultrasound, sono-elastography, and color duplex in evaluation renal allograft complications and correlation with renal function. Results Forty patients (26 males and 14 females) who underwent renal transplantation were included. Their ages ranging from 10:52 years; they all subjected to ultrasound, color Doppler, sono-elastography, and histopathology. The studded patients were divided into 3 groups according to histopathology: patient with normal results, patients with ATI, and patients with CAI. The difference between the mean elasticity values between the three groups was statistically highly significant (p value < 0.001) with high specificity, sensitivity, and accuracy in differentiating ATI and normal groups and also CAI and normal groups, while the lowest sensitivity noticed in differentiating between ATI and CAI groups that is mean elasticity was good to differentiating between ATI and normal groups and also between CAI and normal groups while it was less in differentiating between ATI and CAI groups. As regards the RI, the highest sensitivity of the RI was in differentiating ATI and normal with high sensitivity, specificity, and accuracy, and the lowest sensitivity, specificity, and accuracy of RI were in differentiating CAI and normal groups. Conclusion Transplanted renal allograft could be assessed by combined US, color duplex Doppler, and sono-elastography examination; also we can detect posttransplant complications early. Sono-elastography could be an efficient noninvasive method to diagnose and monitor kidney allograft rejection and follow-up of the renal allograft, which may give a further and possibly earlier prognostic index for chronic dysfunction in addition to serum creatinine.

scholarly journals Validation of Lung EpiCheck®, a novel methylation-based blood assay, for the detection of lung cancer in European and Chinese high-risk individuals

2020 ◽  
pp. 2002682
Author(s):  
Mina Gaga ◽  
Joanna Chorostowska-Wynimko ◽  
Ildikó Horváth ◽  
Martin C Tammemagi ◽  
David Shitrit ◽  
...  
Keyword(s):  
Risk Factors ◽  
Lung Cancer ◽  
Predictive Accuracy ◽  
Early Stage ◽  
Lung Cancer Screening ◽  
High Sensitivity ◽  
High Specificity ◽  
Case Control ◽  
Early Stage Nsclc ◽  
Sensitivity Specificity

AimLung cancer screening reduces mortality. We aim to validate the performance of Lung EpiCheck®, a 6-marker panel methylation-based plasma test, in the detection of lung cancer in European and Chinese samples.MethodsA case-control European training set (102 lung cancer cases/265 controls) was used to define the panel and algorithm. Two cut-offs were selected, low cut-off (LCO) for high sensitivity and high cut-off (HCO) for high specificity. The performance was validated in case-control European and Chinese validation sets (cases/controls: 179/137 and 30/15).ResultsThe European and Chinese validation sets achieved AUCs of 0.882 and 0.899, respectively. The respective sensitivity/specificity with LCO were 87.2%/64.2% and 76.7%/93.3% and with HCO were 74.3%/90.5% and 56.7%/100.0%, respectively. Stage I NSCLC sensitivity in European and Chinese samples with LCO was 78.4% and 70.0% and with HCO was 62.2% and 30.0%, respectively. SCLC was represented only in the European set and sensitivities with LCO and HCO were 100.0% and 93.3%. In multivariable analyses of the European validation set, the assay's ability to predict lung cancer was independent of established risk factors (age, smoking, COPD), and overall AUC was 0.942.ConclusionsLung EpiCheck demonstrated strong performance in lung cancer prediction in case-control European and Chinese samples, detecting high proportions of early stage NSCLC and SCLC and significantly improving predictive accuracy when added to established risk factors. Prospective studies are required to confirm these findings. Utilising such a simple and inexpensive blood test has the potential to improve compliance and broaden access to screening for at-risk populations.

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