scholarly journals Evaluation of anti-SARS-CoV-2 antibody testing in asymptomatic or mild COVID-19 patients in outbreak on a cruise ship

2021 ◽  
Author(s):  
Norihito Kaku ◽  
Fumitaka Nishimura ◽  
Yui Shigeishi ◽  
Rina Tachiki ◽  
Hironori Sakai ◽  
...  
Keyword(s):  
Genetic Test ◽  
False Negative ◽  
Enzyme Linked Immunosorbent Assay ◽  
Cruise Ship ◽  
Igg Antibodies ◽  
Antibody Testing ◽  
Predictive Values ◽  
Blood Samples ◽  
Negative Results ◽  
Genetic Test Results

AbstractBackgroundA few studies on antibody testing have focused on asymptomatic or mild coronavirus disease 2019 (COVID-19) patients with low initial anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody responses. Anti-SARS-CoV-2 antibody-testing performance was evaluated using blood samples from asymptomatic or mild COVID-19 patients.MethodsBlood samples were collected from 143 COVID-19 patients during an outbreak on a cruise ship 3 weeks after diagnosis. Simultaneously, a second SARS-CoV-2 genetic test was performed. Samples stored before the COVID-19 pandemic were also used to evaluate the lateral flow immunochromatographic assay (LFA) and electrochemiluminescence immunoassay (ECLIA). Titers of anti-SARS-CoV-2 IgM and IgG antibodies against the nucleocapsid and spike proteins were measured using the enzyme-linked immunosorbent assay to compare false-negative- with positive-result samples.ResultsSensitivity, specificity, positive-predictive, and negative-predictive values of LFA-detected IgM antibodies were 0.231, 1.000, 1.000, and 0.613, respectively; those of LFA-detected IgG antibodies were 0.483, 0.989, 0.972, and 0.601, respectively; and those of ECLIA-detected total antibodies were 0.783, 1.000, 1.000, and 0.848, respectively. IgM-, IgG-, and total-antibody positivity rates in the patients with negative results from the second genetic testing were 22.9%, 47.6%, and 72.4%, respectively. All antibody titers, especially those of the IgG antibody against nucleocapsid protein, were significantly lower in blood samples with false-negative results than in those with positive results.ConclusionsThese findings suggest that anti-SARS-CoV-2 antibody testing has lower performance in asymptomatic or mild COVID-19 patients than required in the guidelines, and situations in which it is useful are limited.Key pointsAnti-SARS-CoV-2 antibody testing in asymptomatic or mild COVID-19 patients is lower than the required clinical sensitivity, although it may be useful in patients at 3–4 weeks after symptom onset but with negative SARS-CoV-2 genetic test results.

scholarly journals Performance of anti-SARS-CoV-2 antibody testing in asymptomatic or mild COVID-19 patients: A retrospective study in outbreak on a cruise ship

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0257452
Author(s):  
Norihito Kaku ◽  
Fumitaka Nishimura ◽  
Yui Shigeishi ◽  
Rina Tachiki ◽  
Hironori Sakai ◽  
...  
Keyword(s):  
False Negative ◽  
Enzyme Linked Immunosorbent Assay ◽  
Cruise Ship ◽  
Igg Antibodies ◽  
Antibody Testing ◽  
Predictive Values ◽  
Blood Samples ◽  
Negative Results ◽  
Sensitivity Specificity

Objectives A few studies on antibody testing have focused on asymptomatic or mild coronavirus disease 2019 (COVID-19) patients with low initial anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody responses. Anti-SARS-CoV-2 antibody-testing performance was evaluated using blood samples from asymptomatic or mild COVID-19 patients. Methods Blood samples were collected from 143 COVID-19 patients during an outbreak on a cruise ship 3 weeks after diagnosis. Simultaneously, a follow-up SARS-CoV-2 genetic test was performed. Samples stored before the COVID-19 pandemic were also used to evaluate the lateral flow immunochromatographic assay (LFA) and electrochemiluminescence immunoassay (ECLIA). Titers of anti-SARS-CoV-2 IgM and IgG antibodies against the nucleocapsid and spike proteins were measured using the enzyme-linked immunosorbent assay to confirm which antibodies were influenced on LFA- and ECLIA- false-negative result in crew-member samples. Results Sensitivity, specificity, positive-predictive, and negative-predictive values of LFA-detected IgM antibodies were 0.231, 1.000, 1.000, and 0.613, respectively; those of LFA-detected IgG antibodies were 0.483, 0.989, 0.972, and 0.601, respectively; and those of ECLIA-detected total antibodies were 0.783, 1.000, 1.000, and 0.848, respectively. All antibody titers measured using ELISA were significantly lower in blood samples with negative results than in those with positive results in both LFA and ECLIA. In the patients with negative results from the follow-up genetic testing, IgM-, IgG-, and total-antibody positivity rates were 22.9%, 47.6%, and 72.4%, respectively. Conclusions These findings suggest that anti-SARS-CoV-2 antibody testing has lower performance in asymptomatic or mild COVID-19 patients than required in the guidelines.

scholarly journals Detection of Leishmania infantum in Dogs by PCR with Lymph Node Aspirates and Blood

1999 ◽  
Vol 37 (9) ◽  
pp. 2931-2935 ◽  
Author(s):  
S. Reale ◽  
L. Maxia ◽  
F. Vitale ◽  
N. S. Glorioso ◽  
S. Caracappa ◽  
...  
Keyword(s):  
Lymph Node ◽  
Leishmania Infantum ◽  
Blot Hybridization ◽  
False Negative ◽  
Clinical Signs ◽  
Leishmania Braziliensis ◽  
Antibody Testing ◽  
Dot Blot ◽  
Predictive Values ◽  
Blood Samples

The PCR technique was applied to the diagnosis of leishmaniasis in dogs, both serologically negative and positive. DNA was taken from lymph node aspirates and blood. The primers 13a and 13b, derived fromLeishmania amazonies and Leishmania braziliensis kinetoplast DNA (kDNA), also amplifiedLeishmania infantum IPT1 constant region of minicircle kDNA. The amplified fragment is 116 bp long. It was cloned and the sequence was determined. A 70-bp inner fragment was designed and used as a probe in dot blot hybridization. A group of 124 dogs was examined, 37 of which showed typical symptoms of disease. PCR was performed on 124 blood samples and 52 lymph node aspirates. Using microscopic examination as the “gold standard,” we calculated sensitivity, specificity, and positive and negative predictive values of 100% using lymph node aspirates and values of 85, 80, 95, and 57%, respectively, using blood samples. We found that 40% of the animals without lesions and 38% of the animals with clinical signs gave false-negative results by indirect immunofluorescence antibody testing. These animals could contribute to the spreading of infection among dogs, and represent a potential risk for human health as well.

scholarly journals Evaluation and Diagnostic Usefulness of Domestic and Imported Enzyme-Linked Immunosorbent Assays for Detection of Human Immunodeficiency Virus Type 1 Antibody in India

2005 ◽  
Vol 12 (12) ◽  
pp. 1425-1428 ◽  
Author(s):  
H. Syed Iqbal ◽  
Suniti Solomon ◽  
K. G. Murugavel ◽  
Sunil Suhas Solomon ◽  
P. Balakrishnan
Keyword(s):  
Human Immunodeficiency Virus ◽  
False Negative ◽  
Confirmatory Test ◽  
Enzyme Linked Immunosorbent Assay ◽  
Antibody Testing ◽  
Negative Results ◽  
Hiv Test ◽  
Immunodeficiency Virus ◽  
Hiv Antibodies ◽  
Hiv 1

ABSTRACT Diagnosis of human immunodeficiency virus (HIV) infection is important for patient management and prevention of new infections. The number of test kits available for the detection of HIV antibodies is unprecedented. In order to identify appropriate test kits, we evaluated a variety of commercial kits manufactured abroad as well as in India. The plasma and serum specimens (n = 264) were collected from individuals attending the Voluntary Counseling and Testing Centre at the YRG Centre for AIDS and Education. The specimens were used to evaluate six commercially available HIV test kits: Enzaids HIV 1+2, HIV-CheX, Murex HIV-1.2.0, Genscreen HIV 1/2 version 2, Vironostika HIV Uni-Form II Ag/Ab, and CombAids RS Advantage. High sensitivities and specificities (≥99%) were observed for the Enzaids, Murex, Vironostika, and CombAids assays. HIV-CheX showed the highest number of false-positive and false-negative results. The Genscreen test also gave many false positives. The study indicated that the Enzaids, Murex, and Vironostika enzyme-linked immunosorbent assay kits and the CombAids RS Advantage rapid assay could be used to achieve acceptable results for the detection of HIV antibodies. A combination of two tests is recommended to optimize the efficiency of HIV antibody testing algorithms, especially when evaluation with an HIV Western blot confirmatory test is not possible.

scholarly journals Sensitivity, Specificity, and Predictive Values of ThreeSalmonella Rapid Detection Kits Using Fresh and Frozen Poultry Environmental Samples versus Those of Standard Plating

1999 ◽  
Vol 65 (3) ◽  
pp. 1055-1060 ◽  
Author(s):  
Melissa O. Peplow ◽  
Maria Correa-Prisant ◽  
Martha E. Stebbins ◽  
Frank Jones ◽  
Peter Davies
Keyword(s):  
Rapid Detection ◽  
Environmental Samples ◽  
False Negative ◽  
Food Samples ◽  
Detection Methods ◽  
Enzyme Linked Immunosorbent Assay ◽  
Culture Methods ◽  
Predictive Values ◽  
Negative Results ◽  
Rapid Tests

ABSTRACT To reduce human exposure to Salmonella spp. in poultry products, broiler chicken flocks have been tested by culture methods. Since the standard techniques may take 3 to 5 days, rapid detection methods have been developed. In this study we tested the performance of three rapid tests originally developed for food samples by using environmental samples obtained from poultry houses. These rapid tests were Reveal, an enzyme-linked immunosorbent assay from Neogen Corp.; BIND, a bacterial ice nucleation detection method from Idetek Corp.; and a filter monitor method from Future Medical Technologies, Inc. For the standard culture, brilliant green with novabiocin and xylose–lysine–tergitol-4 agar were used for presumptive identification, and identities were confirmed by using poly-O antisera. Environmental samples were collected from farms belonging to an integrated poultry company prior to chick placement and 1 week before slaughter. Sensitivities, specificities, and predictive values with 95% confidence intervals were calculated. Statistical differences were determined by using McNemar’s chi square test. The sensitivities of the different tests were not stable, varying widely between sample times, and were affected by freezing of the samples. All of the rapid tests had low sensitivities, which led to many false-negative results. All tests were able to detect Salmonella spp. at a concentration of 10 CFU/ml in at least one of four trials. The BIND and Reveal tests were simple to use with multiple samples and reduced laboratory time by up to 1 day. Based on our results, we do not recommend that any of these rapid tests, in their present state of development, be utilized with environmental samples collected with drag swabs.

scholarly journals Evaluation of Recombinant Proteins of Burkholderia mallei for Serodiagnosis of Glanders

2012 ◽  
Vol 19 (8) ◽  
pp. 1193-1198 ◽  
Author(s):  
Vijai Pal ◽  
Subodh Kumar ◽  
Praveen Malik ◽  
Ganga Prasad Rai
Keyword(s):  
Sensitivity And Specificity ◽  
Recombinant Proteins ◽  
False Negative ◽  
Enzyme Linked Immunosorbent Assay ◽  
Burkholderia Mallei ◽  
Content Type ◽  
Whole Cells ◽  
Negative Results ◽  
Elisa Format ◽  
Low Sensitivity

ABSTRACTGlanders is a contagious disease caused by the Gram-negative bacillusBurkholderia mallei. The number of equine glanders outbreaks has increased steadily during the last decade. The disease must be reported to the Office International des Epizooties, Paris, France. Glanders serodiagnosis is hampered by the considerable number of false positives and negatives of the internationally prescribed tests. The major problem leading to the low sensitivity and specificity of the complement fixation test (CFT) and enzyme-linked immunosorbent assay (ELISA) has been linked to the test antigens currently used, i.e., crude preparations of whole cells. False-positive results obtained from other diagnostic tests utilizing crude antigens lead to financial losses to animal owners, and false-negative results can turn a risk into a possible threat. In this study, we report on the identification of diagnostic targets using bioinformatics tools for serodiagnosis of glanders. The identified gene sequences were cloned and expressed as recombinant proteins. The purified recombinant proteins ofB. malleiwere used in an indirect ELISA format for serodiagnosis of glanders. Two recombinant proteins, 0375H and 0375TH, exhibited 100% sensitivity and specificity for glanders diagnosis. The proteins also did not cross-react with sera from patients with the closely related disease melioidosis. The results of this investigation highlight the potential of recombinant 0375H and 0375TH proteins in specific and sensitive diagnosis of glanders.

Measles antibodies and response to vaccination in children aged less than 14 months: implications for age of vaccination

2011 ◽  
Vol 140 (9) ◽  
pp. 1599-1606 ◽  
Author(s):  
E. BORRÀS ◽  
L. URBIZTONDO ◽  
J. COSTA ◽  
J. BATALLA ◽  
N. TORNER ◽  
...  
Keyword(s):  
Immunosorbent Assay ◽  
Maternal Antibodies ◽  
Passive Immunity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Igg Antibodies ◽  
Blood Samples ◽  
Measles Outbreak ◽  
Measles Antibodies ◽  
Measles Vaccination

SUMMARYPassive immunity against measles decreases during the first months of life. The objective of this study was to determine titres of measles antibodies in children aged 9–14 months and their mothers before vaccination, and the children's response to vaccination. Blood samples were collected by capillary puncture before and 28 days after vaccination. Samples were obtained between February and June 2007 during an ongoing measles outbreak. Titres of specific measles IgG antibodies were determined by enzyme-linked immunosorbent assay. Seroconversion was defined as the presence of antibodies after vaccination in subjects without antibodies before vaccination. Maternal antibodies were present in 37·7% of all 69 children included and in 45·1% of children aged 9 months. Of the 51 children in whom a second sample was obtained, 31 (60·8%) were seronegative before vaccination and 61·3% seroconverted. Interference of maternal antibodies was 30%. Advancing the first dose of measles vaccination from 15 to 12 months is a correct strategy, given the increase in the time of susceptibility of infants to measles.

scholarly journals Average Weighted Accuracy: Pragmatic Analysis for a Rapid Diagnostics in Categorizing Acute Lung Infections (RADICAL) Study

2019 ◽  
Vol 70 (12) ◽  
pp. 2736-2742 ◽  
Author(s):  
Ying Liu ◽  
Ephraim L Tsalik ◽  
Yunyun Jiang ◽  
Emily R Ko ◽  
Christopher W Woods ◽  
...  
Keyword(s):  
Diagnostic Test ◽  
Diagnostic Yield ◽  
False Negative ◽  
Rapid Diagnostics ◽  
Likelihood Ratios ◽  
Clinical Value ◽  
Predictive Values ◽  
Negative Results ◽  
Treatment Standard ◽  
Lung Infections

Abstract Patient management relies on diagnostic information to identify appropriate treatment. Standard evaluations of diagnostic tests consist of estimating sensitivity, specificity, positive/negative predictive values, likelihood ratios, and accuracy. Although useful, these metrics do not convey the tests’ clinical value, which is critical to informing decision-making. Full appreciation of the clinical impact of a diagnostic test requires analyses that integrate sensitivity and specificity, account for the disease prevalence within the population of test application, and account for the relative importance of specificity vs sensitivity by considering the clinical implications of false-positive and false-negative results. We developed average weighted accuracy (AWA), representing a pragmatic metric of diagnostic yield or global utility of a diagnostic test. AWA can be used to compare test alternatives, even across different studies. We apply the AWA methodology to evaluate a new diagnostic test developed in the Rapid Diagnostics in Categorizing Acute Lung Infections (RADICAL) study.

The role of ultrasonography in the diagnosis of talocalcaneal coalitions

2020 ◽  
pp. 028418512094491
Author(s):  
Tiezheng Wang ◽  
Hengtao Qi ◽  
Kai Rong ◽  
Shuqian Zhang ◽  
Shougang Bao ◽  
...  
Keyword(s):  
False Negative ◽  
Fibrous Tissue ◽  
Joint Space ◽  
Clinical Suspicion ◽  
Youden Index ◽  
Imaging Method ◽  
Predictive Values ◽  
Negative Results ◽  
Reduced Space ◽  
Sensitivity Specificity

Background Patients with talocalcaneal coalitions (TCC) often undergo computed tomography (CT). However, ultrasonography diagnosis of TCC has been seldom done according to the literature. Purpose To investigate the accuracy of ultrasonography in diagnosing TCC compared to CT. Material and Methods Ninety-seven consecutive patients with a clinical suspicion of TCC were included. Ultrasonography was used to assess the classification and complication of TCC. The main sonographic criteria for a positive diagnosis in cases of osseous coalition were the joint space between the medial surface of talar head and the underlying sustentaculum tali of calcaneus disappearing and being replaced by a continuous hyperechoic bony structure. In cases of fibrous coalition, ultrasonography revealed a reduced space of the joint associated with an irregular, angular appearance of its outline and hypoechoic fibrous tissue inside. These data were compared with CT findings. κ statistic was applied to determine the level of agreement. The sensitivity, specificity, positive and negative predictive values, accuracy, and Youden index of ultrasonography as a diagnostic method were assessed. Results Ultrasonography findings were positive in 20 of 97 patients with a clinical suspicion of TCC. The diagnosis was confirmed by CT in 21 patients. There were one false-positive result and two false-negative results by ultrasonography. The κ value was 0.907. The sensitivity, specificity, positive and negative predictive values, accuracy, and Youden index of ultrasonography were 90.5%, 98.7%, 95.0%, 97.4%, 96.9%, and 0.892, respectively. Conclusion Ultrasonography could be a reliable, accurate, and non-radioactive diagnostic imaging method in diagnosis of patients with suspected TCC.

Exploring 'best practice' for nucleic acid detection of Neisseria gonorrhoeae

Sexual Health ◽  
2008 ◽  
Vol 5 (1) ◽  
pp. 17 ◽  
Author(s):  
David M. Whiley ◽  
Suzanne M. Garland ◽  
Geoffrey Harnett ◽  
Gary Lum ◽  
David W. Smith ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Neisseria Gonorrhoeae ◽  
Best Practice ◽  
Current Knowledge ◽  
False Negative ◽  
High Sensitivity ◽  
Nucleic Acid Detection ◽  
Predictive Values ◽  
Neisseria Species ◽  
Negative Results

Nucleic acid detection tests (NADT) have considerable benefits for the detection of Neisseria gonorrhoeae (GC), including high sensitivity across a range of specimen types and use under widely differing settings and conditions. However, sexual health practitioners and others who use data generated by NADT for GC should be aware of some important limitations of these tests. False-positive results caused by cross reaction with commensal Neisseria species have been observed in many assays, and have lead to unacceptably low positive-predictive values in some patient populations. Further, false-negative results can be caused by GC sequence variation, with some gonococci lacking certain NADT target sequences. This review examines the issues associated with gonococcal NADT and considers best practice for use of these assays based on current knowledge. We emphasise the need for supplementary testing and extensive assay validation, and suggest appropriate strategies for these requirements irrespective of the setting in which they are used. Further, we highlight the need to maintain culture-based testing for certain specimen sites as well as for antimicrobial resistance surveillance.

scholarly journals Diagnostic Performance of Hrp2 Based Diagnostic Test Kits and Frequency of Pfhrp2 Gene Deletion in Plasmodium falciparum Isolates of Osogbo, Southwestern Nigeria

2021 ◽  
pp. 20-25
Author(s):  
A. S. Nassar ◽  
A. S. Bakarey ◽  
A. A. Abdulazeez ◽  
O. O. Fayemi
Keyword(s):  
Plasmodium Falciparum ◽  
Diagnostic Test ◽  
Gene Deletion ◽  
False Negative ◽  
University Teaching ◽  
Pcr Analysis ◽  
Southwestern Nigeria ◽  
Blood Samples ◽  
Negative Results ◽  
Test Kit

Introduction: The introduction of P. falciparum encoded HRP-2 based malaria Rapid Diagnostic Test (RDT) kits is widely accepted in Nigeria and worldwide as a simplified form of diagnosis and a cheaper alternative to the microscopy technique (gold standard). However, deletion of Pfhrp2 gene contributes to false negative results and large number of such deletions has been reported in advanced countries thereby highlighting the importance of surveillance to detect such deletions in our local environment. Methodology: Microscopy as well as RDT techniques (using Rapid malaria test kit: SD BIOLINE Malaria Ag P.f/Pv, South Korea) were carried out on the blood samples of three hundred and twenty-three (323) febrile subjects attending Ladoke Akintola University Teaching Hospital, Osogbo, Osun State Nigeria. PCR analysis was also conducted on 50 blood samples that were positive for microscopy but negative for RDT. Results: The results from the study revealed that microscopy had a sensitivity of 99% and specificity of 99.2%. The RDT however had a sensitivity of 100% and a specificity of 60.1%. Fifty (50) samples that were positive for microscopy but negative for RDT were subjected to further PCR examination to detect the possible deletion of the Pfhrp-2 gene and the result revealed that the gene was present in 39 (78%) of the blood samples while remaining 11 (22%) samples lacked the gene which could possibly be the reason for the negative results obtained using the RDT kits. Conclusion: This study provides evidence of low level of presence of Pfhrp-2 gene deletion of Plasmodium falciparum parasites in our healthcare facility setting in Osogbo, Nigeria.

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