scholarly journals Performance of Seven SARS-CoV-2 Self-Tests Based on Saliva, Anterior Nasal and Nasopharyngeal Swabs Corrected for Infectiousness in Real-Life Conditions: A Cross-Sectional Test Accuracy Study

Diagnostics ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1567
Author(s):  
Miroslav Homza ◽  
Hana Zelena ◽  
Jaroslav Janosek ◽  
Hana Tomaskova ◽  
Eduard Jezo ◽  
...  
Keyword(s):  
Real Life ◽  
High Capacity ◽  
Nasopharyngeal Swab ◽  
Test Accuracy ◽  
Cross Sectional ◽  
Predictive Values ◽  
Nasal Swabs ◽  
Accuracy Study ◽  
Testing Center ◽  
Antigen Tests

Many studies reported good performance of nasopharyngeal swab-based antigen tests for detecting SARS-CoV-2-positive individuals; however, studies independently evaluating the quality of antigen tests utilizing anterior nasal swabs or saliva swabs are still rare, although such tests are widely used for mass testing. In our study, sensitivities, specificities and predictive values of seven antigen tests for detection of SARS-CoV-2 (one using nasopharyngeal swabs, two using anterior nasal swabs and four using saliva) were evaluated. In a setting of a high-capacity testing center, nasopharyngeal swabs for quantitative PCR (qPCR) were taken and, at the same time, antigen testing was performed in accordance with manufacturers’ instructions for the respective tests. In samples where qPCR and antigen tests yielded different results, virus culture was performed to evaluate the presence of the viable virus. Sensitivities and specificities of individual tests were calculated using both qPCR and qPCR corrected for viability as the reference. In addition, calculations were also performed for data categorized according to the cycle threshold and symptomatic status. The test using nasopharyngeal swabs yielded the best results (sensitivity of 80.6% relative to PCR and 91.2% when corrected for viability) while none of the remaining tests (anterior nasal swab or saliva-based tests) came even close to the WHO criteria for overall sensitivity. Hence, we advise caution when using antigen tests with alternative sampling methods without independent validation.

scholarly journals Information given by websites selling home self-sampling COVID-19 tests: an analysis of accuracy and completeness

BMJ Open ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. e042453
Author(s):  
Sian Taylor-Phillips ◽  
Sarah Berhane ◽  
Alice J Sitch ◽  
Karoline Freeman ◽  
Malcolm James Price ◽  
...  
Keyword(s):  
Best Practice ◽  
Venous Blood ◽  
Test Accuracy ◽  
Cross Sectional ◽  
Predictive Values ◽  
Online Sales ◽  
Online Purchase ◽  
The Uk ◽  
Antibody Tests ◽  
Intended Use

ObjectivesTo assess the accuracy and completeness of information provided by websites selling home self-sampling and testing kits for COVID-19.DesignCross-sectional observational study.SettingAll websites (n=27) selling direct to user home self-sampling and testing kits for COVID-19 (41 tests) in the UK (39 tests) and USA (two tests) identified by a website search on 23 May 2020.Main outcome measuresThirteen predefined basic information items to communicate to a user, including who should be tested, when and how testing should be done, test accuracy, and interpretation of results.ResultsMany websites did not provide the name or manufacturer of the test (32/41; 78%), when to use the test (10/41; 24%), test accuracy (12/41; 29%), and how to interpret results (21/41; 51%). Sensitivity and specificity were the most commonly reported test accuracy measures (either reported for 27/41 [66%] tests): we could only link these figures to manufacturers’ documents or publications for four (10%) tests. Predictive values, most relevant to users, were rarely reported (five [12%] tests reported positive predictive values). For molecular virus tests, 9/23 (39%) websites explained that test positives should self-isolate, and 8/23 (35%) explained that test negatives may still have the disease. For antibody tests, 12/18 (67%) websites explained that testing positive does not necessarily infer immunity from future infection. Seven (39%) websites selling antibody tests claimed the test had a CE mark, when they were for a different intended use (venous blood rather than finger-prick samples).ConclusionsAt the point of online purchase of home self-sampling COVID-19 tests, users in the UK are provided with incomplete, and, in some cases, misleading information on test accuracy, intended use, and test interpretation. Best practice guidance for communication about tests to the public should be developed and enforced for online sales of COVID-19 tests.

scholarly journals Prevalence of asymptomatic SARS-CoV-2-positive individuals in the general population of northern Italy and evaluation of a diagnostic serological ELISA test: a cross-sectional study protocol

BMJ Open ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. e040036
Author(s):  
Massimo Guerriero ◽  
Zeno Bisoffi ◽  
Albino Poli ◽  
Claudio Micheletto ◽  
Carlo Pomari
Keyword(s):  
General Population ◽  
Study Protocol ◽  
Latent Class ◽  
Serological Test ◽  
Statistical Technique ◽  
Elisa Test ◽  
Nasopharyngeal Swab ◽  
Cross Sectional ◽  
Predictive Values ◽  
Study Results

IntroductionAs of 30 April 2020, the novel betacoronavirus SARS-CoV-2 had infected more than 3 172 000 individuals, killing over 224 000 people and spreading to more than 200 countries. Italy was the most affected country in Europe and the third most affected in the world in terms of the number of cases. Therefore, the aims of this study are: (1) to estimate the prevalence of asymptomatic SARS-CoV-2-positive individuals among the general population of Verona; (2) to assess the accuracy (sensitivity, specificity and predictive values) of an ELISA serological test for the screening of SARS-CoV-2.Methods and analysisThe study will be carried out on a random sample of subjects aged at least 10 years from the general population of Verona. Participants will undergo the measurement of vital parameters (oxygen saturation measured by oximeter, respiratory rate and body temperature detected by laser thermometer), the administration of a COVID-19-related symptoms questionnaire, the collection of a blood sample and a nasopharyngeal swab. Our evaluation will include the statistical technique of Latent Class Analysis, which will be the basis for the estimation of prevalence.Ethics and disseminationThe study protocol has been approved by the Ethics Committee of Verona and Rovigo provinces on 15 April 2020 (internal protocol number 2641CESC). The study results will be submitted for publication in international, peer-reviewed journals and the complete dataset will be deposited in a public repository. Most relevant data will be made available to policy-makers as well as disseminated to stakeholders and to the community.

MACE versus MoCA: equivalence or superiority? Pragmatic diagnostic test accuracy study

2017 ◽  
Vol 29 (6) ◽  
pp. 931-937 ◽  
Author(s):  
A.J. Larner
Keyword(s):  
Secondary Care ◽  
Characteristic Curve ◽  
High Sensitivity ◽  
Screening Instrument ◽  
Test Accuracy ◽  
Cognitive Screening ◽  
Net Benefit ◽  
Dementia Diagnosis ◽  
Predictive Values ◽  
Accuracy Study

ABSTRACTBackground:The Mini-Addenbrooke's Cognitive Examination (MACE) is a new brief cognitive screening instrument for dementia and mild cognitive impairment (MCI). Historical data suggest that MACE may be comparable to the Montreal Cognitive Assessment (MoCA), a well-established cognitive screening instrument, in secondary care settings, but no head-to-head study has been reported hitherto.Methods:A pragmatic diagnostic accuracy study of MACE and MoCA was undertaken in consecutive patients referred over the course of one year to a neurology-led Cognitive Function Clinic, comparing their performance for the diagnosis of dementia and MCI using various test metrics.Results:In a cohort of 260 patients with dementia and MCI prevalence of 17% and 29%, respectively, both MACE and MoCA were quick and easy to use and acceptable to patients. Both tests had high sensitivity (>0.9) and large effect sizes (Cohen's d) for diagnosis of both dementia and MCI but low specificity and positive predictive values. Area under the receiver operating characteristic curve was excellent for dementia diagnosis (both >0.9) but less good for MCI (MoCA good and MACE fair). In contrast, weighted comparison suggested test equivalence for dementia diagnosis but with a slight net benefit for MACE for MCI diagnosis.Conclusions:MACE is an acceptable and accurate test for the assessment of cognitive problems, with performance comparable to MoCA. MACE appears to be a viable alternative to MoCA for testing patients with cognitive complaints in a secondary care setting.

MACE for the Diagnosis of Dementia and MCI: 3-Year Pragmatic Diagnostic Test Accuracy Study

2018 ◽  
Vol 45 (5-6) ◽  
pp. 300-307 ◽  
Author(s):  
John C. Williamson ◽  
Andrew J. Larner
Keyword(s):  
Diagnostic Test ◽  
Cognitive Disorders ◽  
High Sensitivity ◽  
Diagnostic Test Accuracy ◽  
Test Accuracy ◽  
Cognitive Screening ◽  
Predictive Values ◽  
Diagnosis Of Dementia ◽  
Accuracy Study ◽  
Secondary Care Setting

Background/Aims: The Mini-Addenbrooke’s Cognitive Examination (MACE) is a relatively new short cognitive screening instrument for the detection of patients with dementia and mild cognitive impairment (MCI). Few studies of the MACE have been reported hitherto. The aim of this study was to undertake a pragmatic diagnostic test accuracy study of MACE in a large cohort of patients seen in a dedicated cognitive disorders clinic. Methods: MACE was administered to consecutive patients referred to a neurology-led Cognitive Function Clinic over the course of 3 years to assess its performance for the diagnosis of dementia and MCI using various test metrics. Results: In a cohort of 599 patients, the prevalence of dementia and MCI by criterion diagnosis was 0.17 and 0.29, respectively. MACE had a high sensitivity (> 0.9) and negative predictive values (> 0.8) with large effect sizes (Cohen’s d > 1) for the diagnosis of both dementia and MCI but a low specificity (< 0.5) and positive predictive values (≤0.5). Conclusion: MACE is an acceptable test for the assessment of cognitive complaints in a secondary care setting with good metrics for identifying cases of both dementia and MCI.

scholarly journals Evaluation of Hookworm Diagnosis Techniques from Patients in Amhara Region, Ethiopia: Cross sectional study

2020 ◽  
Author(s):  
Ayalew Jejaw Zeleke ◽  
Ayenew Addisu ◽  
Yalewayker Tegegne ◽  
Meseret Birhanie ◽  
Tekeba Sisay ◽  
...  
Keyword(s):  
Infection Intensity ◽  
Cross Sectional Study ◽  
Test Tube ◽  
Test Accuracy ◽  
Sectional Study ◽  
Amhara Region ◽  
Cross Sectional ◽  
Gold Standard Method ◽  
Predictive Values ◽  
Diagnosis Accuracy

Abstract Background: Inappropriate diagnosis could intimidate the prevention and control of Hookworm infection. This study was aimed at evaluating the performance of Hookworm diagnosis methods.Methods: An institution based cross sectional study was conducted in Amhara region, Ethiopia. The study subjects were selected conveniently. Sensitivity, specificity, predictive values, test accuracy and agreements of the different hookworm diagnosis methods, namely; Test Tube Flotation (TFT), MacMaster (MM), Formol Ether Concentration (FEC), Kato katz (KK), and Direct wet mount microscopy (DWMM) were calculated. Composite reference standard (CRS) was used as a gold standard method. Kappa (κ) test was used to measure the level of agreement between diagnosis tests. Moreover, t-test was used to compare the diagnostic performance of the diagnosis methods.Result: a total of 389 stool samples were collected from patients in the study. The overall prevalence of hookworm was 63.24%. Test Tube Flotation (TFT) was found to be the highest both in terms of sensitivity and diagnosis accuracy (100%). MacMaster (MM) was the second most sensitive test (68.7%), followed by FEC (44.3%) and KK (38.2%). On the other hand, DWMM had the lowest sensitivity (37.4%) and its diagnosis accuracy was also the least (60%). Only TFT had a perfect (Agreement=100%, kappa=1) with the CRS. The sensitivity of DWMM, KK, and FEC showed an increase in sensitivity as a function of increasing intensity of infection, but TFT and MM methods were not affected by the infection intensity. Conclusion: Hookworm is still a public health problem in the study area. TFT is by far more sensitive than MM, FEC, KK and DWMM techniques.

scholarly journals Clinical Validation of Automated and Rapid MariPOC SARS-CoV-2 Antigen Test

2021 ◽  
Author(s):  
Juha M. Koskinen ◽  
Petri Antikainen ◽  
Kristina Hotakainen ◽  
Anu Haveri ◽  
Niina Ikonen ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Solid Phase ◽  
High Capacity ◽  
Nasopharyngeal Swab ◽  
Nucleocapsid Proteins ◽  
Clinical Sensitivity ◽  
Qrt Pcr ◽  
Photon Excitation ◽  
Antigen Tests ◽  
Asymptomatic Individuals

Abstract COVID-19 diagnostics was quickly ramped up worldwide early 2020 based on the detection of viral RNA. However, based on the scientific knowledge for pre-existing coronaviruses, it was expected that the SARS-CoV-2 RNA will be detected from symptomatic and at significant rates also from asymptomatic individuals due to persistence of non-infectious RNA. To increase the efficacy of diagnostics, surveillance, screening and pandemic control, rapid methods, such as antigen tests, are needed for decentralized testing and to assess infectiousness. A novel automated mariPOC SARS-CoV-2 test was developed for the detection of conserved structural viral nucleocapsid proteins. The test utilizes sophisticated optical laser technology for two-photon excitation and individual detection of immunoassay solid-phase particles. We validated the new method against qRT-PCR. Sensitivity of the test was 100.0% (13/13) directly from nasopharyngeal swab specimens and 84.4% (38/45) from swab specimens in undefined transport mediums. Specificity of the test was 100.0% (201/201). The test's limit of detection was 2.7 TCID50/test. It showed no cross-reactions. Our study shows that the new test can detect infectious individuals already in 20 minutes with clinical sensitivity close to qRT-PCR. The mariPOC is a versatile platform for syndromic testing and for high capacity infection control screening of infectious individuals.

scholarly journals Clinical validation of automated and rapid mariPOC SARS-CoV-2 antigen test

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Juha M. Koskinen ◽  
Petri Antikainen ◽  
Kristina Hotakainen ◽  
Anu Haveri ◽  
Niina Ikonen ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Solid Phase ◽  
High Capacity ◽  
Nasopharyngeal Swab ◽  
Nucleocapsid Proteins ◽  
Clinical Sensitivity ◽  
Qrt Pcr ◽  
Photon Excitation ◽  
Antigen Tests ◽  
Asymptomatic Individuals

AbstractCOVID-19 diagnostics was quickly ramped up worldwide early 2020 based on the detection of viral RNA. However, based on the scientific knowledge for pre-existing coronaviruses, it was expected that the SARS-CoV-2 RNA will be detected from symptomatic and at significant rates also from asymptomatic individuals due to persistence of non-infectious RNA. To increase the efficacy of diagnostics, surveillance, screening and pandemic control, rapid methods, such as antigen tests, are needed for decentralized testing and to assess infectiousness. A novel automated mariPOC SARS-CoV-2 test was developed for the detection of conserved structural viral nucleocapsid proteins. The test utilizes sophisticated optical laser technology for two-photon excitation and individual detection of immunoassay solid-phase particles. We validated the new method against qRT-PCR. Sensitivity of the test was 100.0% (13/13) directly from nasopharyngeal swab specimens and 84.4% (38/45) from swab specimens in undefined transport mediums. Specificity of the test was 100.0% (201/201). The test's limit of detection was 2.7 TCID50/test. It showed no cross-reactions. Our study shows that the new test can detect infectious individuals already in 20 min with clinical sensitivity close to qRT-PCR. The mariPOC is a versatile platform for syndromic testing and for high capacity infection control screening of infectious individuals.

scholarly journals Information given by websites selling home self-sampling COVID-19 tests: An analysis of accuracy and completeness

2020 ◽  
Author(s):  
Sian Taylor-Phillips ◽  
Sarah Berhane ◽  
Alice Sitch ◽  
Karoline Freeman ◽  
Malcolm Price ◽  
...  
Keyword(s):  
Best Practice ◽  
Venous Blood ◽  
Test Accuracy ◽  
Cross Sectional ◽  
Predictive Values ◽  
Online Sales ◽  
Online Purchase ◽  
The Uk ◽  
Antibody Tests ◽  
Intended Use

Objectives: To assess the accuracy and completeness of information provided by websites selling home self-sampling and testing kits for COVID-19. Design: Cross-sectional observational study. Setting: All websites (n=27) selling direct to user home self-sampling and testing for COVID-19 (41 tests) in the UK (39 tests) and US (2 tests) identified by a website search on 23rd May 2020. Main outcome measures: Thirteen predefined basic information items to communicate to a user, including who should be tested, when and how testing should be done, test accuracy, and interpretation of results. Results: Many websites did not provide the name or manufacturer of the test (32/41; 78%), when to use the test (10/41; 24%), test accuracy (12/41; 29%), and how to interpret results (21/41; 51%). Sensitivity and specificity were the most commonly reported test accuracy measures (either reported for 27/41 (66%) tests); we could only link these figures to manufacturers documents or publications for four (10%) tests. Predictive values, most relevant to users, were rarely reported (five [12%] tests reported positive predictive values). For molecular virus tests, 9/23 (39%) websites explained that test positives should self-isolate, and 8/23 (35%) explained that test negatives may still have the disease. For antibody tests, 12/18 (67%) websites explained that testing positive does not necessarily infer immunity from future infection. Seven (39%) websites selling antibody tests claimed the test had a CE mark, when they were for a different intended use (venous blood rather than finger-prick samples). Conclusions: At the point of online purchase of home self-sampling COVID-19 tests, users in the UK are provided with incomplete, and in some cases misleading information on test accuracy, intended use and test interpretation. Best practice guidance for communication about tests to the public should be developed and enforced for online sales of COVID-19 tests.

scholarly journals Clinical Validation of Automated and Rapid mariPOC SARS-CoV-2 Antigen Test

2021 ◽  
Author(s):  
Juha M. Koskinen ◽  
Petri Antikainen ◽  
Kristina Hotakainen ◽  
Anu Haveri ◽  
Niina Ikonen ◽  
...  
Keyword(s):  
Sensitivity And Specificity ◽  
Limit Of Detection ◽  
Clinical Performance ◽  
High Capacity ◽  
Nasopharyngeal Swab ◽  
Analytical Sensitivity ◽  
Clinical Sensitivity ◽  
Qrt Pcr ◽  
Antigen Tests ◽  
Novel Coronavirus

ABSTRACTNovel SARS coronavirus causing COVID-19 was recognized in late 2019. Diagnostics was quickly ramped up worldwide based on the detection of viral RNA. Based on the scientific knowledge for pre-existing coronaviruses, it was expected that the RNA of this novel coronavirus will be detected at significant rates from symptomatic and asymptomatic individuals due to existence of non-infectious RNA. To increase the efficacy of diagnostics, surveillance, screening and pandemic control, rapid methods, such as antigen tests, are needed for decentralized testing and to assess infectiousness. The objectives were to verify analytical sensitivity and specificity, and assess the clinical sensitivity, specificity and usability of a novel automated mariPOC SARS-CoV-2 test based on sophisticated optical laser technology detecting viral structure proteins. Analytical performance was verified using bacterial and viral preparations. Clinical performance of the test was evaluated against qRT-PCR in a retrospective study with nasopharyngeal swab specimens (N=211) collected from symptomatic patients suspected of acute SARS-CoV-2 infections. Sensitivity and specificity of the mariPOC test were 92.3% (12/13) and 100.0% (198/198), respectively. The test’s limit of detection was 22 PFU/test and it had no cross-reactions with the tested respiratory microbes. Our study shows that the mariPOC can detect infectious individuals already in 20 minutes while clinical sensitivity close to qRT-PCR is achieved in two hours or less. The test targets conserved epitopes of SARS-CoV-2 nucleoprotein, making it robust against strain variations. The new test is a promising and versatile tool for syndromic testing of symptomatic cases and for high capacity infection control screening.

scholarly journals Excellent option for mass testing during the SARS-CoV-2 pandemic: painless self-collection and direct RT-qPCR

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Eva Kriegova ◽  
Regina Fillerova ◽  
Milan Raska ◽  
Jirina Manakova ◽  
Martin Dihel ◽  
...  
Keyword(s):  
Cohort Study ◽  
Early Identification ◽  
Nasal Swab ◽  
Healthcare Personnel ◽  
Nasopharyngeal Swab ◽  
Grey Zone ◽  
Predictive Values ◽  
Nasal Swabs ◽  
Large Prospective Cohort Study ◽  
Large Prospective Cohort

AbstractThe early identification of asymptomatic yet infectious cases is vital to curb the 2019 coronavirus (COVID-19) pandemic and to control the disease in the post-pandemic era. In this paper, we propose a fast, inexpensive and high-throughput approach using painless nasal-swab self-collection followed by direct RT-qPCR for the sensitive PCR detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This approach was validated in a large prospective cohort study of 1038 subjects, analysed simultaneously using (1) nasopharyngeal swabs obtained with the assistance of healthcare personnel and analysed by classic two-step RT-qPCR on RNA isolates and (2) nasal swabs obtained by self-collection and analysed with direct RT-qPCR. Of these subjects, 28.6% tested positive for SARS-CoV-2 using nasopharyngeal swab sampling. Our direct RT-qPCR approach for self-collected nasal swabs performed well with results similar to those of the two-step RT-qPCR on RNA isolates, achieving 0.99 positive and 0.98 negative predictive values (cycle threshold [Ct] < 37). Our research also reports on grey-zone viraemia, including samples with near-cut-off Ct values (Ct ≥ 37). In all investigated subjects (n = 20) with grey-zone viraemia, the ultra-small viral load disappeared within hours or days with no symptoms. Overall, this study underscores the importance of painless nasal-swab self-collection and direct RT-qPCR for mass testing during the SARS-CoV-2 pandemic and in the post-pandemic era.

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