scholarly journals Estimating the proportion of SARS-CoV-2 infections reported through diagnostic testing

2021 ◽  
Author(s):  
Ewan Colman ◽  
Jessica Enright ◽  
Gavrila A. Puspitarani ◽  
Rowland R. Kao
Keyword(s):  
Diagnostic Test ◽  
Diagnostic Testing ◽  
False Negative ◽  
Positive Diagnosis ◽  
Test Sensitivity ◽  
Natural Factors ◽  
Period Distribution ◽  
Flow Device ◽  
The Uk ◽  
Critical Metric

The number of positive diagnostic tests for SARS-CoV-2 is a critical metric that is commonly used to assess epidemic severity and the efficacy of current levels of control. However, a proportion of individuals infected with SARS-CoV-2 may never receive a diagnostic test, while many of those who are tested may receive a false negative result. Consequently, cases reported through testing of symptomatic individuals represent only a fraction of the total number of infections, and this proportion is expected to vary depending on changes in natural factors and variability in test-seeking behaviour. Here we combine a number of data sources from England to estimate the proportion of infections that have resulted in a positive diagnosis. Using published estimates of the incubation period distribution and time-dependent test sensitivity, we estimate SARS-CoV-2 incidence from daily reported diagnostic test data. By calibrating this estimate against surveillance data we find that approximately 25% of infections were consistently reported through diagnostic testing before November 2020. This percentage increased through the final months of 2020, predominantly in regions with a large presence of the the UK variant of concern (VOC), before falling rapidly in the last two weeks of January 2021. These changes are not explained by variation in rates of lateral flow device or PCR testing, but are consistent with there being an increased probability for the VOC that infection will result in an eventual positive diagnosis.

scholarly journals An imperfect tool: COVID-19 ‘test & trace’ success relies on minimising the impact of false negatives and continuation of physical distancing

2020 ◽  
Author(s):  
Emma L. Davis ◽  
Tim C. D. Lucas ◽  
Anna Borlase ◽  
Timothy M Pollington ◽  
Sam Abbot ◽  
...  
Keyword(s):  
Process Model ◽  
Diagnostic Testing ◽  
False Negative ◽  
Contact Tracing ◽  
Parameter Estimates ◽  
Sensitivity Testing ◽  
Test Sensitivity ◽  
Negative Results ◽  
The Impact

AbstractBackgroundFollowing a consistent decline in COVID-19-related deaths in the UK throughout May 2020, it is recognised that contact tracing will be vital to relaxing physical distancing measures. The increasingly evident role of asymptomatic and pre-symptomatic transmission means testing is central to control, but test sensitivity estimates are as low as 65%.MethodsWe extend an existing UK-focused branching process model for contact tracing, adding diagnostic testing and refining parameter estimates to demonstrate the impact of poor test sensitivity and suggest mitigation methods. We also investigate the role of super-spreading events, providing estimates of the relationship between infections, cases detected and hospitalisations, and consider how tracing coverage and speed affects outbreak risk.FindingsIncorporating poor sensitivity testing into tracing protocols could reduce efficacy, due to false negative results impacting isolation duration. However, a 7-day isolation period for all negative-testing individuals could mitigate this effect. Similarly, reducing delays to testing following exposure has a negligible impact on the risk of future outbreaks, but could undermine control if negative-testing individuals immediately cease isolating. Even 100% tracing of contacts will miss cases, which could prompt large localised outbreaks if physical distancing measures are relaxed prematurely.InterpretationIt is imperative that test results are interpreted with caution due to high false-negative rates and that contact tracing is used in combination with physical distancing measures. If the risks associated with imperfect test sensitivity are mitigated, we find that contact tracing can facilitate control when the reproduction number with physical distancing, RS, is less than 1·5.

scholarly journals Evaluation of SARS-CoV-2 antigen-based rapid diagnostic kits in Pakistan: formulation of COVID-19 national testing strategy

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Umar Saeed ◽  
Sara Rizwan Uppal ◽  
Zahra Zahid Piracha ◽  
Azhar Rasheed ◽  
Zubair Aftab ◽  
...  
Keyword(s):  
Gold Standard ◽  
Injection Drug Users ◽  
Drug Users ◽  
Diagnostic Testing ◽  
False Negative ◽  
Cross Sectional Study ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
Cross Sectional ◽  
Negative Results

AbstractRapid diagnosis of SARS-CoV-2 during pandemic enables timely treatment and prevention of COVID-19. Evaluating the accuracy and reliability of rapid diagnostic testing kits is crucial for surveillance and diagnosis of SARS-CoV-2 infections in general population, injection drug users, multi-transfused populations, healthcare workers, prisoners, barbers and other high risk populations. The aim of this study was to evaluate performance and effectiveness of nasopharyngeal swab (NSP) and saliva based rapid antigen detection testing kits in comparison with USFDA approved triple target gold standard real-time polymerase chain reaction. A cross-sectional study was conducted on 33,000 COVID-19 suspected patients. From RT-PCR positive patients, nasopharyngeal swab (NSP) and saliva samples were obtained for evaluation of rapid COVID-19 testing kits (RDT). 100/33,000 (0.3%) of specimens were RT-PCR positive for SARS-CoV-2. Among RT-PCR positive, 62% were males, 34% were females, and 4% were children. The NSP-RDT (Lepu Medical China) analysis revealed 53% reactivity among males, 58% reactivity among females, and 25% reactivity among children. However saliva based RDT (Lepu Medical China) analysis showed 21% reactivity among males and 23% among females, and no reactivity in children. False negative results were significantly more pronounced in saliva based RDT as compared to NSP-RDT. The sensitivity of these NSP-RDT and saliva based RDT were 52% and 21% respectively. The RDTs evaluated in this study showed limited sensitivities in comparison to gold standard RT-PCR, indicating that there is a dire need in Pakistan for development of suitable testing to improve accurate COVID-19 diagnosis in line with national demands.

scholarly journals Observed Differences in Diagnostic Test Accuracy between Patient Subgroups: Is It Real or Due to Reference Standard Misclassification?

2007 ◽  
Vol 53 (10) ◽  
pp. 1725-1729 ◽  
Author(s):  
Corné Biesheuvel ◽  
Les Irwig ◽  
Patrick Bossuyt
Keyword(s):  
Clinical Practice ◽  
Diagnostic Test ◽  
Sensitivity And Specificity ◽  
Diagnostic Test Accuracy ◽  
Test Accuracy ◽  
Reference Standard ◽  
Target Condition ◽  
Test Sensitivity ◽  
The Past ◽  
Patient Subgroups

Abstract Before a new test is introduced in clinical practice, its accuracy should be assessed. In the past decade, researchers have put an increased emphasis on exploring differences in test sensitivity and specificity between patient subgroups. If the reference standard is imperfect and the prevalence of the target condition differs among subgroups, apparent differences in test sensitivity and specificity between subgroups may be caused by reference standard misclassification. We provide guidance on how to determine whether observed differences may be explained by reference standard misclassification. Such misclassification may be ascertained by examining how the apparent sensitivity and specificity change with the prevalence of the target condition in the subgroups.

scholarly journals ANALISIS MISKONSEPSI SISWA MENGGUNAKAN THREE TIER DIAGNOSTIC TEST BERBASIS OPEN ENDED QUESTION

2021 ◽  
Vol 9 (3) ◽  
pp. 276-291
Author(s):  
Mawaddah Mawaddah ◽  
Yandi Heryandi
Keyword(s):  
Data Collection ◽  
Diagnostic Test ◽  
Diagnostic Tests ◽  
Research Method ◽  
False Negative ◽  
Large Percentage ◽  
Sampling Techniques ◽  
Research Subjects ◽  
False Negatives ◽  
Clinical Interviews

This study aims to: (1) find out the misconceptions experienced by students in the material of similarity and congruence by using three-tier diagnostic tests based on open-ended questions. (2) find out the large percentage of students' misconceptions on the similarity and congruence material using a three-tier diagnostic test based on open-ended questions. The research method used was descriptive qualitative. The data collection instruments used were clinical interviews and three-tier diagnostic tests based on open-ended questions. This study was conducted in the SMP Negeri 2 Palimanan. The research subjects were selected using purposive sampling techniques so that 33 students were selected from 330 students. The results of the analysis of the three-tier diagnostic test based on open-ended questions showed that (1) the misconceptions that occurred in the material of similarity and congruence of 2D shapes included pure misconceptions, false positives, and false negatives. (2) the percentage of misconceptions experienced in the material of similarity and congruence 2D shapes as a whole was 50.2% with a large percentage of pure misconceptions 32.4%, false-positive 15.6%, and false-negative 2.2%

scholarly journals Early introductions and community transmission of SARS-CoV-2 variant B.1.1.7 in the United States

2021 ◽  
Author(s):  
Tara Alpert ◽  
Erica Lasek-Nesselquist ◽  
Anderson F. Brito ◽  
Andrew L. Valesano ◽  
Jessica Rothman ◽  
...  
Keyword(s):  
Public Health ◽  
United States ◽  
New York ◽  
Diagnostic Testing ◽  
The United States ◽  
International Travel ◽  
Health Concern ◽  
Public Health Response ◽  
Community Transmission ◽  
The Uk

SummaryThe emergence and spread of SARS-CoV-2 lineage B.1.1.7, first detected in the United Kingdom, has become a national public health concern in the United States because of its increased transmissibility. Over 500 COVID-19 cases associated with this variant have been detected since December 2020, but its local establishment and pathways of spread are relatively unknown. Using travel, genomic, and diagnostic testing data, we highlight the primary ports of entry for B.1.1.7 in the US and locations of possible underreporting of B.1.1.7 cases. New York, which receives the most international travel from the UK, is likely one of the key hubs for introductions and domestic spread. Finally, we provide evidence for increased community transmission in several states. Thus, genomic surveillance for B.1.1.7 and other variants urgently needs to be enhanced to better inform the public health response.

scholarly journals Sensitivity and specificity of a rapid diagnostic test for chronic Chagas disease at a referral center in Brazil - can it be included as a standard serological diagnostic test in the clinical practice of a referral center?

2021 ◽  
Vol 1 ◽  
pp. e1236
Author(s):  
Alejandro M. Hasslocher-Moreno ◽  
Ingebourg Georg ◽  
Luiz H. C. Sangenis ◽  
Mauro F. F. Mediano
Keyword(s):  
Clinical Practice ◽  
Diagnostic Test ◽  
Chagas Disease ◽  
Sensitivity And Specificity ◽  
Diagnostic Testing ◽  
Chronic Phase ◽  
Neglected Tropical Disease ◽  
Rapid Diagnostic Testing ◽  
Referral Center ◽  
Chronic Chagas Disease

Introduction: Chagas disease (CD) is a neglected tropical disease. In the chronic phase of CD, the diagnosis is essentially serologic. Conventional reactions are currently in use. More recently, the use of rapid diagnostic testing (RDT) is indicated when conventional techniques are not available. Objective: To evaluate the sensitivity and specificity of RDTs for chronic CD diagnosis. Methodology: Individuals under suspicion of CD were evaluated using ELISA, Chemiluminescence (ChLIA) and RDT tests. Results: The RDT showed 95.1% sensitivity and 96.7% specificity, respectively. Conclusion: The findings of the present study showed that RDT used in the diagnosis of CD at a referral center in Brazil were not able to detect all CD cases when compared to Elisa and ChLIA.

scholarly journals Tuberculosis diagnosis and treatment under uncertainty

2019 ◽  
Vol 116 (46) ◽  
pp. 22990-22997
Author(s):  
Rachel Cassidy ◽  
Charles F. Manski
Keyword(s):  
Diagnostic Test ◽  
Diagnostic Testing ◽  
World Health ◽  
Smear Microscopy ◽  
Theoretic Model ◽  
Test Accuracy ◽  
Partial Knowledge ◽  
Deep Uncertainty ◽  
Tuberculosis Diagnosis ◽  
Health Organization

In 2017, 1.6 million people worldwide died from tuberculosis (TB). A new TB diagnostic test—Xpert MTB/RIF from Cepheid—was endorsed by the World Health Organization in 2010. Trials demonstrated that Xpert is faster and has greater sensitivity and specificity than smear microscopy—the most common sputum-based diagnostic test. However, subsequent trials found no impact of introducing Xpert on morbidity and mortality. We present a decision-theoretic model of how a clinician might decide whether to order Xpert or other tests for TB, and whether to treat a patient, with or without test results. Our first result characterizes the conditions under which it is optimal to perform empirical treatment; that is, treatment without diagnostic testing. We then examine the implications for decision making of partial knowledge of TB prevalence or test accuracy. This partial knowledge generates ambiguity, also known as deep uncertainty, about the best testing and treatment policy. In the presence of such ambiguity, we show the usefulness of diversification of testing and treatment.

False Positive and False Negative Radon Measurement Results Due to Uncertainties in Seasonal Correction Factors

1994 ◽  
Vol 56 (1-4) ◽  
pp. 291-292 ◽  
Author(s):  
K.D. Cliff ◽  
J.C.H. Miles ◽  
S.P. Naismith
Keyword(s):  
False Positive ◽  
False Negative ◽  
Geometric Standard Deviation ◽  
Correction Factors ◽  
Radon Measurement ◽  
Negative Results ◽  
False Negative Results ◽  
Initial Survey ◽  
The Uk ◽  
Radon Measurements

Abstract Data from the UK national survey of radon in 2300 homes has been re-analysed to determine the uncertainty in seasonal correction factors applied to measurements of less than l year. The required correction factor for each six-month result was calculated from the known annual average for the appropriate home. The seasonal correction factors derived for each month were found to be approximately log-normally distributed, with an average geometric standard deviation of 1.36. Following this initial survey, radon measurements have been made in more than 80,000 homes in southwest England to determine whether they are above the UK radon Action level of 200 Bq.m-3. The measurements were carried out over three months in each case using etched track detectors in two locations in each home, and the results were corrected for the average seasonal variation found in the original UK study of radon in homes. Because of the uncertainty in the seasonal correction factors, households with between 130 and 300 Bq.m-3 were advised to have a second three-month measurement in a different season before deciding whether or not to take remedial action. More than 7000 homes were remonitored for this purpose. The results are analysed to show the number of false positive and false negative results that would have been reported if advice had been based solely on the initial measurement. It is shown that the present scheme results in extremely small numbers of false positive and false negative results.

The NHS diabetic eye screening programme

2019 ◽  
Vol 13 (12) ◽  
pp. 596-599
Author(s):  
Ian Peate
Keyword(s):  
Healthy Lifestyle ◽  
False Negative ◽  
Young Person ◽  
Screening Process ◽  
Negative Results ◽  
Eye Screening ◽  
Increased Risk ◽  
Diabetic Eye Screening ◽  
The Individual ◽  
The Uk

The NHS diabetic eye screening (DES) programme is one of the young person and adult NHS population screening programmes that are available in the UK. The various NHS screening programmes identify those people who appear healthy, but could be at increased risk of a disease or condition. Screening is not the same as diagnosis and there will always be a possibility of some false positive and false negative results. This article in the series provides the reader with details about the DES programme. A brief overview of the anatomy of the eye is provided and the screening process is described. The healthcare assistant and assistant practitioner (HCA and AP) have a key role to play in encouraging and emphasising the importance of screening, as well as helping the individual maintain a healthy lifestyle.

scholarly journals Regional, sex, and age differences in diagnostic testing among participants in the NAVIGATE-ESUS trial

2019 ◽  
pp. 174749301988452 ◽  
Author(s):  
Antonio Arauz ◽  
Fabiola Serrano ◽  
Lesly A Pearce ◽  
Scott E Kasner ◽  
Sebastian F Ameriso ◽  
...  
Keyword(s):  
Latin America ◽  
North America ◽  
East Asia ◽  
Eastern Europe ◽  
Diagnostic Test ◽  
Western Europe ◽  
Diagnostic Testing ◽  
Multivariable Logistic Regression Model ◽  
Mr Angiogram ◽  
Sex And Age Differences

Background and aim The diagnosis of embolic stroke of undetermined source (ESUS) is based on excluding other more likely stroke etiologies, and therefore diagnostic testing plays an especially crucial role. Our objective was to compare the diagnostic testing by region, sex, and age among the participants of NAVIGATE-ESUS trial. Methods Participants were grouped according to five global regions (North America, Latin America, Western Europe, Eastern Europe and East Asia), age (<60, 60–74, and >75 years), and sex. Frequencies of each diagnostic test within areas of echocardiography, cardiac rhythm monitoring, and arterial imaging were described and compared across groups. A multivariable logistic regression model for each diagnostic test was fit to assess the independent influence of each of region, age, and sex and likelihood of testing. Results We included 6985 patients in the analysis (918 from North America; 746 from Latin America; 2853 from Western Europe; 1118 from Eastern Europe; 1350 from East Asia). Average age (highest in Western Europe (69 years), lowest in Eastern Europe (65 years)), % females (highest in Latin America (44%) and lowest in East Asia (31%)), and use of each diagnostic test varied significantly across regions. Region, but not sex, was independently associated with use of each diagnostic test examined. Transesophageal echocardiography and either CT or MR angiogram were more often used in younger patients. Conclusion Diagnostic testing differed by region, and less frequently by age, but not by sex. Our findings reflect the existing variations in global practice in diagnostic testing in ESUS patients.

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