+Is it possible to make a common reference standard for D‐dimer measurements?: Communication from the ISTH SSC Subcommittee on Fibrinolysis

Abstract Background: The use of D-dimer assays as a rule-out test for deep venous thrombosis (DVT) is controversial. To clarify this issue we performed a systematic review of the relevant literature. Methods: We identified eligible studies, using MEDLINE entries from February 1995 through October 2003, supplemented by a review of bibliographies of relevant articles. Studies reporting accuracy evaluations comparing D-dimer test results with lower extremity ultrasound or venography in symptomatic patients with suspected acute DVT were selected for review. Two reviewers critically appraised each study independently according to previously established methodologic standards for diagnostic test research. Those studies judged to be of highest quality were designated Level 1. Results: The 23 Level 1 studies reported data on 21 different D-dimer assays. There was wide variation in assay sensitivity, specificity, and negative predictive values, and major differences in methodology of reviewed studies. A multivariate analysis of assay performance, controlling for sample size, DVT prevalence, reference standard, and patient mix, found few differences among the assays in effect on test performance as measured by diagnostic odds ratio. Increasing prevalence of DVT was associated with poorer test performance (P = 0.01), whereas the choice of venography as the reference standard was associated with better test performance (P <0.005). Conclusions: Explanations for the wide variation in assay performance include differences in biochemical and technical characteristics of the assays, heterogeneity and small size of patient groups, and bias introduced by choice of reference standards. Assay sensitivity and negative predictive value were frequently <90%, uncharacteristic of a good rule-out test. General use of D-dimer assays as a stand-alone test for the diagnosis of DVT is not supported by the literature.

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A framework for the development of a global standardised marine taxon reference image database (SMarTaR-ID) to support image-based analyses

10.1101/670786 ◽

2019 ◽

Author(s):

Kerry L. Howell ◽

Jaime S. Davies ◽

A. Louise Allcock ◽

Andreia Braga-Henriques ◽

Pål Buhl-Mortensen ◽

...

Keyword(s):

Sustainable Use ◽

Image Data ◽

Marine Species ◽

Marine Ecology ◽

Reference Image ◽

Reference Standard ◽

Quality Of Data ◽

Common Reference ◽

The North ◽

Taxonomic Groups

AbstractVideo and image data are regularly used in the field of benthic ecology to document biodiversity. However, their use is subject to a number of challenges, principally the identification of taxa within the images without associated physical specimens. The challenge of applying traditional taxonomic keys to the identification of fauna from images has led to the development of personal, group, or institution level reference image catalogues of operational taxonomic units (OTUs) or morphospecies. Lack of standardisation among these reference catalogues has led to problems with observer bias and the inability to combine datasets across studies. In addition, lack of a common reference standard is stifling efforts in the application of artificial intelligence to taxon identification. Using the North Atlantic deep sea as a case study, we propose a database structure to facilitate standardisation of morphospecies image catalogues between research groups and support future use in multiple front-end applications. We also propose a framework for coordination of international efforts to develop reference guides for the identification of marine species from images. The proposed structure follows the Darwin Core standard to allow integration with existing databases. We suggest a management framework where high-level taxonomic groups are curated by a regional team, consisting of both end users and taxonomic experts. We identify a mechanism by which overall quality of data within a common reference guide could be raised over the next decade. Finally, we discuss the role of a common reference standard in advancing marine ecology and supporting sustainable use of this ecosystem.

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Systematic review of studies investigating ventilator associated pneumonia diagnostics in intensive care

BMC Pulmonary Medicine ◽

10.1186/s12890-021-01560-0 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Basem Al-Omari ◽

Peter McMeekin ◽

A. Joy Allen ◽

Ahsan R. Akram ◽

Sara Graziadio ◽

...

Keyword(s):

Standard Test ◽

Cochrane Library ◽

Ventilator Associated Pneumonia ◽

Reference Standard ◽

Treatment Unit ◽

Common Reference ◽

Full Text Review ◽

Comprehensive Search ◽

Critical Appraisal Skills ◽

The Cochrane Library

Abstract Background Ventilator-associated pneumonia (VAP) is an important diagnosis in critical care. VAP research is complicated by the lack of agreed diagnostic criteria and reference standard test criteria. Our aim was to review which reference standard tests are used to evaluate novel index tests for suspected VAP. Methods We conducted a comprehensive search using electronic databases and hand reference checks. The Cochrane Library, MEDLINE, CINHAL, EMBASE, and web of science were searched from 2008 until November 2018. All terms related to VAP diagnostics in the intensive treatment unit were used to conduct the search. We adopted a checklist from the critical appraisal skills programme checklist for diagnostic studies to assess the quality of the included studies. Results We identified 2441 records, of which 178 were selected for full-text review. Following methodological examination and quality assessment, 44 studies were included in narrative data synthesis. Thirty-two (72.7%) studies utilised a sole microbiological reference standard; the remaining 12 studies utilised a composite reference standard, nine of which included a mandatory microbiological criterion. Histopathological criteria were optional in four studies but mandatory in none. Conclusions Nearly all reference standards for VAP used in diagnostic test research required some microbiological confirmation of infection, with BAL culture being the most common reference standard used.

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Waste Glass Analytical Bias Correction Using a Reference Standard Glass

MRS Proceedings ◽

10.1557/proc-465-173 ◽

1996 ◽

Vol 465 ◽

Author(s):

Gary L. Smith ◽

Dennis L. Eggett ◽

Harry D. Smith

Keyword(s):

Reference Material ◽

Inductively Coupled Plasma ◽

Analytical Techniques ◽

Atomic Emission ◽

Reference Standard ◽

Analytical Technique ◽

Common Reference ◽

Standard Glass ◽

Analytical Results ◽

Analytical Reference

ABSTRACTAnalytical round robins were established to allow laboratories responsible for the analysis of (nuclear) wastes glasses to compare their analytical capabilities and techniques with one another in a non-competitive atmosphere. In addition the quality of analyses using different analytical techniques on the same materials could be compared. Analytical Round Robin 7 had two primary objectives: 1) to evaluate the effect of using the same analytical reference glass as a reference standard for bias correcting analytical results for all the participating laboratories in making the analyses; and 2) to discuss the analytical methods and results from the participating laboratories between the participants for the purpose of evaluating quality and interlaboratory consistency. This paper will primarily address the first objective.The purpose of an analytical reference material is to bring the analytical results from various laboratories into better agreement by providing them a common reference point No reference glass is likely to be ideal for each element in the glass being analyzed. Obviously, the closer the reference material is to the unknown, the more confidence there will be in the results because less judgement is called for. Use of the reference glass to bias correct analytical results for a standard set of analyses from several laboratories provides the data needed to determine the effectiveness of an Analytical Reference Glass (ARG) in producing interlaboratory agreement. Concurrently, whether or not the analytical results using ARG-1 are more valid or systematically biased can be evaluated using standard statistical methods. The conclusion is that bias correcting with a standard glass such as ARG-1 for results obtained by the inductively coupled plasma - atomic emission spectroscopy (ICP-AES) analytical technique produces more accurate results.

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the LAB: Bilirubin Measurement in the Newborn: Need for a Common Reference Standard in Serum

Hospital Topics ◽

10.1080/00185868.1964.12082793 ◽

1964 ◽

Vol 42 (2) ◽

pp. 53-55

Author(s):

S. Raymond Gambino

Keyword(s):

Reference Standard ◽

Common Reference

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Exclusion of Deep Venous Thrombosis with D-Dimer Testing

Thrombosis and Haemostasis ◽

10.1055/s-0037-1613784 ◽

2000 ◽

Vol 83 (02) ◽

pp. 191-198 ◽

Cited By ~ 123

Author(s):

Henk van den Borne ◽

Marion van der Kolk ◽

Piet de Wild ◽

Ger Janssen ◽

Stan van Uum ◽

...

Keyword(s):

Emergency Department ◽

Venous Thrombosis ◽

Deep Venous Thrombosis ◽

Diagnostic Performance ◽

Reference Range ◽

Clinical Suspicion ◽

Reference Standard ◽

Upper Limit ◽

Conventional Elisa ◽

D Dimer

SummaryIn a direct assay comparison we evaluated the diagnostic performance of 10 novel D-Dimer assays for the exclusion of deep venous thrombosis (DVT). In addition, 3 conventional ELISA D-Dimer assays were included as reference tests. The study was performed in 99 consecutive outpatients referred to the emergency department for clinical suspicion of DVT. Venography was used as reference standard and demonstrated the presence of DVT in 50 patients (6 patients with isolated distal DVT and 44 patients with proximal DVT). The qualitative D-Dimer assays Minutex and SimpliRED and the quantitative BC DD showed overall sensitivities (for proximal and distal DVT) of only 80-83% with specificities that ranged from 87 to 94%. Overall sensitivity was 94% for the qualitative INSTANT I.A. and 98% for the quantitative Turbiquant at a cut-off level equal to the detection limit. Using different cut-off levels a sensitivity of 100% for proximal DVT and for proximal as well as distal DVT could be obtained for NycoCard, IL DD, Liatest, Tinaquant and VIDAS D-Dimer assays with specificities that ranged from 31% (NycoCard) to 71% (VIDAS) for proximal DVT and from 12% (NycoCard) to 47% (IL DD) for overall DVT. At a cut-off level equal to the upper limit of the reference range only Tinaquant and VIDAS showed a sensitivity of 100% for proximal as well as for distal DVT with a specificity of 39% and 41% respectively.The results of this study suggest that the VIDAS and Tinaquant D-Dimer assays have the highest sensitivity for the exclusion of DVT in outpatients. In outpatients that have a low or moderate pretest probability for DVT, these tests may be used in management studies where anticoagulation is withheld on the basis of D-Dimer testing alone.

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Twitter Usage Using Common Reference to Tinnitus

American Journal of Audiology ◽

10.1044/2020_aja-19-00055 ◽

2020 ◽

Vol 29 (2) ◽

pp. 206-217

Author(s):

Jianyuan Ni ◽

Monica L. Bellon-Harn ◽

Jiang Zhang ◽

Yueqing Li ◽

Vinaya Manchaiah

Keyword(s):

Nonprofit Organizations ◽

Temporal Trends ◽

Temporal Analysis ◽

Cross Sectional ◽

For Profit ◽

Common Reference ◽

Personal Experiences ◽

Twitter Users ◽

Sectional Analysis ◽

Share Information

Objective The objective of the study was to examine specific patterns of Twitter usage using common reference to tinnitus. Method The study used cross-sectional analysis of data generated from Twitter data. Twitter content, language, reach, users, accounts, temporal trends, and social networks were examined. Results Around 70,000 tweets were identified and analyzed from May to October 2018. Of the 100 most active Twitter accounts, organizations owned 52%, individuals owned 44%, and 4% of the accounts were unknown. Commercial/for-profit and nonprofit organizations were the most common organization account owners (i.e., 26% and 16%, respectively). Seven unique tweets were identified with a reach of over 400 Twitter users. The greatest reach exceeded 2,000 users. Temporal analysis identified retweet outliers (> 200 retweets per hour) that corresponded to a widely publicized event involving the response of a Twitter user to another user's joke. Content analysis indicated that Twitter is a platform that primarily functions to advocate, share personal experiences, or share information about management of tinnitus rather than to provide social support and build relationships. Conclusions Twitter accounts owned by organizations outnumbered individual accounts, and commercial/for-profit user accounts were the most frequently active organization account type. Analyses of social media use can be helpful in discovering issues of interest to the tinnitus community as well as determining which users and organizations are dominating social network conversations.

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