Resources Repository
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ArticlePublication 2022Comparison of Home Antigen Testing With RT-PCR and Viral Culture During the Course of SARS-CoV-2 Infection
As the availability of at-home self-collected antigen tests for SARS-CoV-2 increases, understanding their efficacy is …
As the availability of at-home self-collected antigen tests for SARS-CoV-2 increases, understanding their efficacy is crucial. A study in San Diego and Denver between January and May 2021 assessed the reliability of these tests against standard RT-PCR tests and viral cultures. Of the 225 participants with confirmed infections, the antigen test sensitivity was found to be 50% during the infectious period, 64% against the same-day RT-PCR, and 84% against the same-day cultures. Sensitivity was highest…
Test Performance | Infectious Diseases | Clinical Care | Culture/Society | Health/Medicine | Science/Technology -
ReviewPublication 2022Diagnostics for COVID-19: Moving from Pandemic Response to Control
Diagnostics are essential in managing the COVID-19 pandemic, with three primary methods for detecting SARS-CoV-2 …
Diagnostics are essential in managing the COVID-19 pandemic, with three primary methods for detecting SARS-CoV-2 infections. Each test type remains vital as we shift from responding to controlling the pandemic. Molecular tests, like PCR, are highly precise in identifying viral RNA and are endorsed by the WHO for confirming cases and guiding public health actions. Antigen rapid tests spot viral proteins and, while less accurate than molecular tests, are quicker, more affordable, simpler, and can…
Test Performance | Infectious Diseases | Health Systems | Clinical Care | Health/Medicine | Science/Technology -
ArticlePublication 2020Testing for SARS-CoV-2 Antibodies
Antibody testing can determine previous exposure to SARS-CoV-2 virus. Recently, the UK government has made …
Antibody testing can determine previous exposure to SARS-CoV-2 virus. Recently, the UK government has made antibody testing available to anyone wanting it, even if there is no clinical indication. The purpose of this article is to provide guidance for when to consider antibody testing in individuals with and without symptoms suggestive of current or past SARS-CoV-2 infection. Key points made by the authors include: (1) antibody testing is likely to be most useful 2 weeks…
Test Performance | Probability/Bayes | Technology Assessment | Infectious Diseases | Clinical Care | Health/Medicine -
ArticlePublication 2020Bayes' Theorem, COVID-19, and Screening Tests
This article reviews the implications of increased testing for COVID-19 using reverse transcriptase polymerase chain …
This article reviews the implications of increased testing for COVID-19 using reverse transcriptase polymerase chain reaction (rRT-PCR) through the application of Bayes’ Theorem for three hypothetical, stylized case scenarios. The scenarios involve three patients with a low, moderate, and high pre-test probability of COVID-19 infection. The category of low probability would include "asymptomatic individuals in a presumed low prevalence environment" and might vary from 10 to 20%. The category of moderate probability would include "individuals…
Test Performance | Probability/Bayes | Infectious Diseases | Clinical Care | Health/Medicine -
ArticlePublication 2020Interpreting COVID-19 Test Results: A Bayesian Approach
This article considers the following question with respect to interpreting the results of polymerase chain reaction …
This article considers the following question with respect to interpreting the results of polymerase chain reaction (PCR) assays from nasal and pharyngeal swabs for COVID-19 to inform clinical decision making: "While a positive result in an acutely ill patient is straightforward, how should physicians interpret negative tests in patients with suspected COVID-19 infection?" Using an assumption of near-perfect specificity of PCR assays for COVID-19, the authors acknowledge the uncertainty of test sensitivity. They consider two clinical scenarios…
Test Performance | Probability/Bayes | Infectious Diseases | Health/Medicine | Science/Technology | Global -
ArticlePublication 2020Translating Population Evidence to Individual Patients
In this paper, the authors describe the differences in population level outcomes compared to individual …
In this paper, the authors describe the differences in population level outcomes compared to individual patients and discuss ways that these are differences. The authors cover topics including the difference between relative and absolute risk and benefit. They use an example of the decision to start anticoagulation in new-onset atrial fibrillation to discuss translating population level evidence to treatment of an individual. These options include generalizability, subgroup analysis, prediction rules, following response to therapy, and even…
Test Performance | Evidence Synthesis | Health Systems | Clinical Care | Health/Medicine -
ArticlePublication 2020Clinical Decision Making: Using a Diagnostic Test
This article is part of a 6-part series on clinical decision making. The authors use …
This article is part of a 6-part series on clinical decision making. The authors use two clinical examples to review the principles of interpreting diagnostic test results. They outline an approach that can be used to determine how to select and apply tests and their results to the practice of internal medicine. Topics covered in the two case studies include sensitivity and specificity, positive predictive and negative predictive value of tests, and how to estimate…
Test Performance | Probability/Bayes | Clinical Care | Health/Medicine -
ArticlePublication 2019Measuring Progress Towards Universal Health Coverage
This article, published in BMJ Global Health, aims to estimate the 2015 national and subnational …
This article, published in BMJ Global Health, aims to estimate the 2015 national and subnational universal health coverage (UHC) service coverage status for Ethiopia. The UHC service coverage index is constructed from the geometric means of component indicators: first, within each of four major categories and then across all components to obtain the final summary index. The authors estimate UHC service coverage at the subnational level using a variety of surveys and routinely collected administrative…
Test Performance | Health Systems | Health/Medicine | Sub-Saharan Africa -
ArticlePublication 2017Cost-Effectiveness of Testing and Treatment for Latent TB
Testing for and treating latent tuberculosis infection (LTBI) is among the main strategies to achieve …
Testing for and treating latent tuberculosis infection (LTBI) is among the main strategies to achieve TB elimination in the United States. This analysis estimated health outcomes, costs, and cost-effectiveness of LTBI testing and treatment among non-US born residents with and without medical comorbidities (e.g., diabetes, HIV infection, and end-stage renal disease). A decision analytic tree and Markov cohort simulation model was used to compare the following strategies: no testing, tuberculin skin test (TST), interferon gamma release assay…
Test Performance | State-Transition | Microsimulation | Cost-Effectiveness Analysis | Infectious Diseases | Chronic Disease/Risk | Health Systems | Economics/Finance | Health/Medicine | Global | North America