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Community-Based Epidemiology: Community Involvement in Defining Social Risk
Published in John T. Pardeck, Charles F. Longino, John W. Murphy, Reason and Rationality in Health and Human Services Delivery, 2014
Despite the public confusion and anxiety over inconsistent epidemiologic reports, it is common to consider epidemiologic methods as the “gold standard” because these methods allow us to assess human health risk directly (Wartenberg & Simon, 1995). By measuring exposures and potentially confounding associated characteristics of individuals, over a period of time, epidemiologic methods provide a powerful means of isolating the effects of clinically significant risk factors. The history of epidemiology is the story of development of ever more powerful and refined methods of assessing health risk: the cross-sectional field survey, case-control studies, prospective cohort studies, multivariate statistical analysis, and the ultimate in modern research methodology-the randomized clinical trial. The randomized double-blinded controlled clinical trial is the most powerful method known to science for isolating and quantifying the effect of a drug, food, or behavioral risk factor, net the effect of other factors.
G
Published in Filomena Pereira-Maxwell, Medical Statistics, 2018
In the context of diagnostic testing, a gold standard is a valid diagnostic tool or method that consistently gives the correct diagnosis (i.e. it is reliable and accurate). In practice, gold standards are rarely 100% accurate. They are simply the best method of diagnosis accord-ing to current dogma. Gold standard tests can be invasive and expensive, and thus may be used in studies that evaluate the accuracy (sensitivity, specificity) of simpler and/or less costly methods. Sackett, in HAYNES et al. (eds., 2006), discusses strategies for improving the accuracy of gold standard tests and measurements. See also clinical measurement.
Diagnostic Tests
Published in Gary L. Rosner, Purushottam W. Laud, Wesley O. Johnson, Bayesian Thinking in Biostatistics, 2021
Gary L. Rosner, Purushottam W. Laud, Wesley O. Johnson
If the outcome of analyses of blood, urine, a mammogram, or a biopsy is a “yes,” or “no,” or a “maybe,” then the procedure used to produce the result is called a diagnostic test. It is often the case that such tests are designed to result in simply yes or no binary outcomes. A key feature of binary diagnostic tests is that they are seldom 100% accurate. Even in the absence of the condition, a test might say “yes.” Similarly, a test may incorrectly declare “no” when the condition is present. When a diagnostic test is perfect, it is often termed a “gold standard” test.
Commentary: statistical analysis of 2 × 2 tables in biomarker studies 1) the four ‘indices of test validity’
Published in Biomarkers, 2022
The basic study design has many possible uses and can be applied to patients, subjects, animals, samples, chemicals. However, for the sake of generality, certain terms used in these articles will be standardised. For simplicity, the individual sample which is tested will be called a ‘case’ and the total set of standard cases that the test is applied to is called the ‘Reference or Standard Material’. An alternative historical term, ‘Gold Standard’ is still commonly used (Greenhaigh 1997). The Gold Standard was defined as ‘the diagnostic test or benchmark that is the best available under reasonable conditions’. There are also ‘silver standards’ ‘Imperfect gold standards’ or ‘Imperfect reference standards’ while Pepe and Feinstein discuss the possibility of ‘Bronze’ or ‘Silver’ Standards.
Longitudinal analysis of tear cathepsin S activity levels in male non-obese diabetic mice suggests its potential as an early stage biomarker of Sjögren’s Syndrome
Published in Biomarkers, 2019
Srikanth R. Janga, Mihir Shah, Yaping Ju, Zhen Meng, Maria C. Edman, Sarah F. Hamm-Alvarez
SS occurs in males and females of all ages, but the majority of patients diagnosed are middle-aged women with a male to female ratio of 1:10 (Ramos-Casals et al.2015); however, ocular and extra-glandular complications may be more serious in men (Mathews et al.2015). Despite being the second most common autoimmune rheumatic disease in the United States, a large subset of SS patients are estimated to remain undiagnosed due to a lack of specific classification criteria and biomarkers (Mavragani and Moutsopoulos 2010). Several classification criteria have been proposed but lack proper validation. In 2002, American and European experts in SS set forth classification criteria that included oral and ocular symptoms, histopathology of SG to confirm lymphocytic infiltration, and elevated serum markers like autoantibodies to Ro (SSA) and La (SSB) (Vitali 2002). However, none of these classifications were endorsed by the American College of Rheumatology (ACR) or the European League Against Rheumatism (EULAR) until, in 2012, the Sjögren’s International Collaborative Clinical Alliance (SICCA) registry developed new classification criteria, which were endorsed by the ACR in the interim (Shiboski et al.2012). Most recently, in 2016, a set of new classification criteria were developed and endorsed by the ACR and EULAR based primarily on hallmark symptoms like histological evaluations and autoantibody profiles (Shiboski et al.2017). Each of these “gold standard” criteria has its own drawbacks, ranging from a lack of specificity to SS to the need for use of invasive methods and the high costs of the assay. Even with these criteria, it still takes ∼3.5 years to diagnose a SS patient (source: https://www.sjogrens.org/home/about-the-foundation/breakthroughgoal-/4yearupdate). Hence, there continues to be a need for specific and noninvasive diagnostic markers for timely diagnosis of SS.
Molecular point-of-care testing in the community pharmacy setting: current status and future prospects
Published in Expert Review of Molecular Diagnostics, 2022
Michael Klepser, Renee R. Koski
A number of characteristics besides performance must be considered when assessing the appropriateness of a CLIA-waived test for use in a community pharmacy. Since most tests are performed as a cash transaction, the cost of the test and associated components (e.g. analyzer, controls) is an important consideration. Data suggest that patients may be willing to pay up to $100 out-of-pocket for pharmacy-based testing services; however, individuals on fixed income may struggle to pay even this much [4,34]. Run time is another important test consideration. A primary attraction for pharmacy-based testing is the rapid availability of results so treatment may be rendered at the visit. If a symptomatic patient must wait more than 20 minutes for results, this may pose a barrier to this care model. Related to run time are channel limitations. For tests requiring analyzers, the number of tests and the length of time that tests must remain in an analyzer can cause testing bottlenecks. Many lateral flow assays allow tests to run on a benchtop and to be inserted into the analyzer for a short period of time to read the results. Conversely, NAATs remain in the analyzer for the entire duration of the test. Therefore, for an analyzer with a single channel, even at a run time of 20 minutes, only three tests can be run per hour. Knowing that most pharmacy-based testing programs will have a relatively low daily testing volume, reagent storage and need to bring reagents to room temperature before use, can be a significant barrier to use in a pharmacy. Also related to testing volume, attention should be paid to the shelf-life of reagents, so tests are not wasted. Another consideration is quality control (QC) requirement. Some tests are packaged with positive and negative controls, whereas some manufacturers require that these be purchased separately. External controls must be run at defined times (i.e. new operator, new shipment of test kits, etc.). The QC requirements are an important consideration not only from the standpoint of purchasing the controls, but also, because a test must be used each time a QC is performed. Frequent QC requirements can become expensive. Test performance and interpretation of results is another important consideration. Sensitivity and specificity are important for understanding how a given test performs compared to a gold-standard and are useful for comparison of various tests with each other. However, regarding clinical interpretation of test results, understanding positive and negative predictive values and what steps to take given a test result and the patient’s pretest probability of having the disease of interest is equally important. Another consideration is the relevance of use in the community pharmacy setting. Given that many retail pharmacies now have private examination or vaccination rooms, any of the POCT for detecting infectious pathogens would be potentially relevant to community pharmacy. The needs of nearby communities and other nearby health-care resources may dictate which tests would be most useful in specific pharmacies.