USING PRE-TEST PROBABILITIES TO MORE EFFECTIVELY UTILIZE POINT-OF-CARE COVID-19 TESTING IN NURSING HOMES.

2020 ◽  
Vol 7 (11) ◽  
pp. 1-6
Keyword(s):  
Nursing Homes ◽  
Risk Mitigation ◽  
Point Of Care ◽  
Nursing Home Residents ◽  
Infectious Agent ◽  
Care Workers ◽  
Increased Risk ◽  
Post Test ◽  
Test Result ◽  
Test Probability

Nursing home residents are at increased risk of contracting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative infectious agent of COVID-19, as a result of exposure to asymptomatic or pre-symptomatic health care workers. In an effort to reopen nursing homes safely, federal agencies have proposed guidelines for testing of staff and residents at regular intervals. To mitigate testing shortages, facilities received antigen point-of-care (POC) testing devices for COVID-19 but without clear guidance on when to select an antigen vs. molecular based test and how to act on a positive or negative test result. This special article presents an algorithm for how to approach pre-test probability in the selection of a certain test and how to use post-test probability to act on a test result in the context of risk mitigation.

scholarly journals 1028. Performance and Patient Acceptability Evaluation of the Chembio DPP® HIV-Syphilis Assay in an Emergency Department

2021 ◽  
Vol 8 (Supplement_1) ◽  
pp. S605-S605
Author(s):  
Kendall N Maliszewski ◽  
Yu-Hsiang Hsieh ◽  
Deanna Myer ◽  
Danielle A Perez ◽  
Charlotte A Gaydos ◽  
...  
Keyword(s):  
Point Of Care ◽  
False Negative ◽  
Standard Of Care ◽  
Patient Acceptability ◽  
Sexually Transmitted ◽  
Before And After ◽  
Post Test ◽  
Sex With Men ◽  
Finger Stick ◽  
Test Result

Abstract Background Emergency departments (EDs) serve as sentinel settings for diagnosing sexually transmitted infections (STIs), including HIV and syphilis. We aimed to assess performance and patient acceptability of a point-of-care (POC) test, the Chembio Dual Path Platform (DPP®) HIV-Syphilis Assay, in an urban ED in Baltimore. Methods 170 patients were enrolled via convenience sampling from Oct 2019 – March 2020 and Jan 2021 – June 2021. Patients eligible were < 70 yrs, men who have sex with men, pregnant without care, had STI concerns, or history of drug use. Subjects received standard of care (SOC) HIV and syphilis testing under institutional laboratory algorithms. Subjects were then tested with the finger-stick POC test and completed a survey, both before and after the POC test to assess subjects’ attitudes about the POC test. Results Comparing the SOC and POC results, 165/170 (97.1%) were test concordant. 3 syphilis POC results were false negative, but reported successful treatment over 10 years prior to enrollment (treponemal antibody remains after treatment). 1 HIV result was false negative and 1 was false positive. Overall the sensitivity and specificity of the HIV POC test were 96.8% (95%CI: 83.3%, 99.9%) and 99.3% (95% CI: 96.1%, 100%), and for syphilis were 85.7% (95%Cl: 63.7%, 97.0%) or 100% (95%CI: 81.5%, 100%), if excluding 3 persons having been successfully treated, and 100% (95% CI: 97.6%, 100%) respectively. The pre-test survey found 67% and 77% of participants were comfortable with a finger-stick test and agreed the POC test result would be as good as the SOC test result, which increased to 96% and 86% in the post-test, respectively, (p< 0.05). At post-test, 86% reported they would feel confident to perform this test at home and 81% would use it at least once per year if it were available. 97% reported they were more likely to seek treatment if receiving a positive result during their ED visit and 91% reported it would reduce their stress/anxiety if receiving a negative test result in the ED. Conclusion Our findings demonstrated satisfactory performance and high patient acceptability of the Chembio DPP® HIV-Syphilis Assay. Given the test is FDA approved, implementation studies are needed to determine whether adoption of this POC test will benefit patients and be consistent with ED workflows. Disclosures Richard E. Rothman, PhD, MD, Chem bio (Grant/Research Support)

scholarly journals A “Clinician’s Probability Calculator” to convert pre-test to post-test probability of COVID-19 , based on method validation from each laboratory

2020 ◽  
Author(s):  
Zoe Brooks ◽  
Saswati Das ◽  
Tom Pliura
Keyword(s):  
Health Staff ◽  
Test Results ◽  
Likelihood Ratios ◽  
Percent Agreement ◽  
Public Health Staff ◽  
Post Test ◽  
Online Calculator ◽  
Test Result ◽  
Post Test Probability ◽  
Test Probability

During coronavirus pandemic testing and identifying the virus has been a unique and constant challenge for the scientific community. In this paper, we discuss a practical solution to help guide clinicians and public health staff with the interpretation of the probability that a positive, or negative, COVID-19 test result indicates an infected person, based on their clinical estimate of pre-test probability of infection. The LinkedIn survey confirmed that the pre-test probability of COVID-19 increases with patient age, known contact, and severity of symptoms, as well as prevalence of disease in the local population. PPA (Positive Percent Agreement, PPA) and NPA (Negative Percent Agreement, specificity), differ between individual methods. Results vary between laboratories and the manufacturer for the same method. The confidence intervals of results vary with the number of samples tested, often adding a large range of possibilities to the reported test result. The online calculator met the objective.The authors postulated that the clinical pre-test probability of COVID-19 increases relative to local prevalence of disease plus patient age, known contact, and severity of symptoms. We conducted a small survey on LinkedIn to confirm that hypothesis. We examined results of PPA (Positive Percent Agreement, sensitivity) and NPA (Negative Percent Agreement, specificity) from 73 individual laboratory experiments for molecular tests for SARS-CoV-2as reported to the FIND database,(1) and for selected methods in FDA EUA submissions (2,3). We calculated likelihood ratios to convert pre-test to post-test probability of disease, then further calculated the number of true and false results expected in every ten positive or negative test results, plus an estimate that one in ‘x’ test results is true. We designed an online calculator to create graphics and text to fulfill the objective. A positive or negative test result from one laboratory conveys a higher probability for the presence or absence of COVID-19 than the same result from another laboratory, depending on clinical pre-test probability of disease plus proven method PPA and NPA in each laboratory. Likelihood ratios and confidence intervals provide valuable information but are seldom used in clinical settings. We recommend that testing laboratories verify PPA and NPA, and utilize a tool such as the “Clinician’s Probability Calculator” to verify acceptable test performance and create reports to help guide clinicians and public health staff with estimation of post-test probability of COVID-19 .

scholarly journals Association Between Nursing Home Crowding and COVID-19 Infection and Mortality in Ontario, Canada

2020 ◽  
Author(s):  
Kevin A. Brown ◽  
Aaron Jones ◽  
Nick Daneman ◽  
Adrienne K. Chan ◽  
Kevin L. Schwartz ◽  
...  
Keyword(s):  
Nursing Home ◽  
Nursing Homes ◽  
Propensity Score Analysis ◽  
Nursing Home Residents ◽  
Complete Information ◽  
Population Based ◽  
Healthcare Personnel ◽  
Score Analysis ◽  
Increased Risk ◽  
Frequent Testing

AbstractImportanceNursing home residents have been disproportionately impacted by the COVID-19 epidemic. Prevention recommendations have emphasized frequent testing of healthcare personnel and residents, but additional strategies are needed to protect nursing home residents.ObjectiveWe developed a reproducible index of nursing home crowding and determined whether crowding was associated with incidence of COVID-19 in the first months of the COVID-19 epidemic.Design, Setting, and ParticipantsPopulation-based retrospective cohort study of over 78,000 residents of 618 distinct nursing homes in Ontario, Canada from March 29 to May 20, 2020.ExposureThe nursing home crowding index equalled the average number of residents per bedroom and bathroom.OutcomesPrimary outcomes included the cumulative incidence of COVID-19 infection and mortality, per 100 residents; introduction of COVID-19 into a home (≥1 resident case) was a negative tracer.ResultsOf 623 homes in Ontario, we obtained complete information on 618 homes (99%) housing 78,607 residents. A total of 5,218 residents (6.6%) developed COVID-19 infection, and 1,452 (1.8%) died with COVID-19 infection as of May 20, 2020. COVID-19 infection was distributed unevenly across nursing homes: 4,496 (86%) of infections occurred in just 63 (10%) of homes. The crowding index ranged across homes from 1.3 (mainly single-occupancy rooms) to 4.0 (exclusively quadruple occupancy rooms); 308 (50%) homes had high crowding index (≥2). Incidence in high crowding index homes was 9.7%, versus 4.5% in low crowding index homes (p<0.001), while COVID-19 mortality was 2.7%, versus 1.3%. The likelihood of COVID-19 introduction did not differ (31.3% vs 30.2%, p=0.79). After adjustment for regional, nursing home, and resident covariates, the crowding index remained associated with increased risk of infection (RR=1.72, 95% Confidence Interval [CI]: 1.11-2.65) and mortality (RR=1.72, 95%CI: 1.03-2.86). Propensity score analysis yielded similar conclusions for infection (RR=2.06, 95%CI: 1.34-3.17) and mortality (RR=2.09, 95%CI: 1.30-3.38). Simulations suggested that converting all 4-bed rooms to 2-bed rooms would have averted 988 (18.9%) infections of COVID-19 and 271 (18.7%) deaths.Conclusions and RelevanceCrowding was associated with higher incidence of COVID-19 infection and mortality. Reducing crowding in nursing homes could prevent future COVID-19 mortality.

scholarly journals Public reporting of antipsychotic prescribing in nursing homes: population-based interrupted time series analyses

2018 ◽  
Vol 28 (2) ◽  
pp. 121-131 ◽  
Author(s):  
Noah M Ivers ◽  
Monica Taljaard ◽  
Vasily Giannakeas ◽  
Catherine Reis ◽  
Evelyn Williams ◽  
...  
Keyword(s):  
Time Series ◽  
Nursing Home ◽  
Nursing Homes ◽  
Mass Media ◽  
Nursing Home Residents ◽  
Public Reporting ◽  
Increased Risk ◽  
Antipsychotic Prescribing ◽  
The Impact ◽  
Newspaper Articles

BackgroundAlthough sometimes appropriate, antipsychotic medications are associated with increased risk of significant adverse events. In 2014, a series of newspaper articles describing high prescribing rates in nursing homes in Ontario, Canada, garnered substantial interest. Subsequently, an online public reporting initiative with home-level data was launched. We examined the impact of these public reporting interventions on antipsychotic prescribing in nursing homes.MethodsTime series analysis of all nursing home residents in Ontario, Canada, between 1 October 2013 and 31 March 2016. The primary outcome was the proportion of residents prescribed antipsychotics each month. Balance measures were prescriptions for common alternative sedating agents (benzodiazepines and/or trazodone). We used segmented regression to assess the effects on prescription trends of the newspaper articles and the online home-level public reporting initiative.ResultsWe included 120 009 nursing home resident admissions across 636 nursing homes. Following the newspaper articles, the proportion of residents prescribed an antipsychotic decreased by 1.28% (95% CI 1.08% to 1.48%) and continued to decrease at a rate of 0.2% per month (95% CI 0.16% to 0.24%). The online public reporting initiative did not alter this trend. Over 3 years, there was a net absolute reduction in antipsychotic prescribing of 6.0% (95% CI 5.1% to 6.9%). Trends for benzodiazepine prescribing did not change as substantially during the period of observation. Trazodone use has been gradually increasing, but its use did not change abruptly at the time of the mass media report or the public reporting initiative.InterpretationThe rapid impact of mass media on prescribing suggests both an opportunity to use this approach to invoke change and a warning to ensure that such reporting occurs responsibly.

scholarly journals “Clinician’s Probability Calculator” to Convert Pre-Test to Post-Test Probability of COVID-19, Based on Method Validation from Each Laboratory

2021 ◽  
Author(s):  
Zoe Brooks ◽  
Saswati Das ◽  
Tom Pliura
Keyword(s):  
Test Performance ◽  
False Negative ◽  
Likelihood Ratios ◽  
Unique Challenge ◽  
Molecular Tests ◽  
Percent Agreement ◽  
Post Test ◽  
Test Result ◽  
Post Test Probability ◽  
Test Probability

Identifying the SARS-CoV-2 virus has been a unique challenge for the scientific community. In this paper, we discuss a practical solution to help guide clinicians with interpretation of the probability that a positive, or negative, COVID-19 test result indicates an infected person, based on their clinical estimate of pre-test probability of infection.The authors conducted a small survey on LinkedIn to confirm that hypothesis that that the clinical pre-test probability of COVID-19 increases relative to local prevalence of disease plus patient age, known contact, and severity of symptoms. We examined results of PPA (Positive Percent Agreement, sensitivity) and NPA (Negative Percent Agreement, specificity) from 73 individual laboratory experiments for molecular tests for SARS-CoV-2 as reported to the FIND database 1, and for selected methods in FDA EUA submissions2,3. Authors calculated likelihood ratios to convert pre-test to post-test probability of disease and designed an online calculator to create graphics and text to report results. Despite best efforts, false positive and false negative Covid-19 test results are unavoidable4,5. A positive or negative test result from one laboratory has a different probability for the presence of disease than the same result from another laboratory. Likelihood ratios and confidence intervals can convert the physician or other healthcare professional&rsquo;s clinical estimate of pre-test probability to post-test probability of disease. Ranges of probabilities differ depending on proven method PPA and NPA in each laboratory. We recommend that laboratories verify PPA and NPA and utilize a the &ldquo;Clinician&rsquo;s Probability Calculator&rdquo; to verify acceptable test performance and create reports to help guide clinicians with estimation of post-test probability of COVID-19.

A Ruler for Interpreting Diagnostic Test Results

2005 ◽  
Vol 44 (01) ◽  
pp. 124-126 ◽  
Author(s):  
W. Lehmacher ◽  
M. Hellmich
Keyword(s):  
Diagnostic Test ◽  
Likelihood Ratio ◽  
Bayes Rule ◽  
Test Results ◽  
Post Test ◽  
Log Odds ◽  
Additive Equation ◽  
Diagnostic Test Result ◽  
Test Result ◽  
Test Probability

Summary Objectives: Bayes’ rule formalizes how the pre-test probability of having a condition of interest is changed by a diagnostic test result to yield the post-test probability of having the condition. To simplify this calculation a geometric solution in form of a ruler is presented. Methods: Using odds and the likelihood ratio of a test result in favor of having the condition of interest, Bayes’ rule can succinctly be expressed as ”the post-test odds equals the pre-test odds times the likelihood ratio”. Taking logarithms of both sides yields an additive equation. Results: The additive log odds equation can easily be solved geometrically. We propose a ruler made of two scales to be adjusted laterally. A different, widely used solution in form of a nomogram was published by Fagan [2]. Conclusions: Whilst use of the nomogram seems more obvious, the ruler may be easier to operate in clinical practice since no straight edge is needed for precise reading. Moreover, the ruler yields more intuitive results because it shows the change in probability due to a given test result on the same scale.

scholarly journals Measurements of Plasma-Free Metanephrines by Immunoassay Versus Urinary Metanephrines and Catecholamines by Liquid Chromatography with Amperometric Detection for the Diagnosis of Pheochromocytoma/Paraganglioma

2020 ◽  
Vol 9 (10) ◽  
pp. 3108
Author(s):  
Wolfgang Raber ◽  
Hans Kotal ◽  
Rodrig Marculescu ◽  
Christian Scheuba ◽  
Martin B. Niederle ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Amperometric Detection ◽  
University Hospital ◽  
Receiver Operating Characteristic Curves ◽  
Post Test ◽  
Male Patients ◽  
Plasma Free Metanephrines ◽  
Test Result ◽  
Test Probability ◽  
Better Than

Studies conflict concerning the use of enzyme immunoassays (EIA) for plasma free metanephrines (P-MNs) vs. other methods for pheochromocytoma/paraganglioma (PPGL) diagnosis. We compared commercially available EIAs for P-MNs with high-pressure liquid chromatography (HPLC) for 24 h-urinary MNs (U-MNs) and -catecholamines (U-CATs). 943 (565 female, 378 male) patients (54 PPGL, 889 Non-PPGL) were studied. Simultaneous measurements of all parameters analyzed at the central lab of our university hospital was mandatory for inclusion. Sensitivity of P-MNs (94.4%) was similar to that of U-MNs (100%), and both were higher than of U-CATs (77.8%), specificity of P-MNs (100%) higher than of U-MNs (73.6%), and similar to U-CATs (99.8%). With the recently proposed downward adjusted ULN of P-MNs to correct for the reported negative bias of the EIAs sensitivity (98.1%) raised non-significantly, but specificity decreased significantly (94.8%). Areas under receiver-operating characteristic curves indicated comparable diagnostic performance of P-MNs (0.989) vs. U-MNs (0.995), both better than U-CATs (0.956). In summary, the EIAs to measure P-MNs performed similarly to U-MNs by HPLC, and both better than U-CATs by HPLC. The post-test probability of PPGL given a positive test result was best for P-MNs, and higher than for the other pairs of analytes. Downward corrections of ULN of P-MNs did not improve test performances.

scholarly journals Exploring views and experiences of how infections are detected and managed in practice by nurses, care workers and manager’s in nursing homes in England and Sweden: a survey protocol

BMJ Open ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. e038390
Author(s):  
N Carey ◽  
Nouf Alkhamees ◽  
Anna Cox ◽  
Marta Sund-Levander ◽  
Pia Tingström ◽  
...  
Keyword(s):  
Nursing Home ◽  
Decision Support ◽  
Nursing Homes ◽  
Early Detection ◽  
Hospital Admissions ◽  
Nursing Home Residents ◽  
User Engagement ◽  
Cross Sectional ◽  
Support Tool ◽  
Care Workers

IntroductionIn order to avoid unnecessary hospital admission and associated complications, there is an urgent need to improve the early detection of infection in nursing home residents. Monitoring signs and symptoms with checklists or aids called decision support tools may help nursing home staff to detect infection in residents, particularly during the current COVID-19 pandemic.We plan to conduct a survey exploring views and experiences of how infections are detected and managed in practice by nurses, care workers and managers in nursing homes in England and Sweden.Methods and analysisAn international cross-sectional descriptive survey, using a pretested questionnaire, will be used to explore nurses, care workers and managers views and experiences of how infections are detected and managed in practice in nursing homes. Data will be analysed descriptively and univariate associations between personal and organisational factors explored. This will help identify important factors related to awareness, knowledge, attitudes, belief and skills likely to affect future implementation of a decision support tool for the early detection of infection in nursing home residents.Ethics and disseminationThis study was approved using the self-certification process at the University of Surrey and Linköping University ethics committee (Approval 2018/514-32) in 2018. Study findings will be disseminated through community/stakeholder/service user engagement events in each country, publication in academic peer-reviewed journals and conference presentations. A LAY summary will be provided to participants who indicate they would like to receive this information.This is the first stage of a plan of work to revise and evaluate the Early Detection of Infection Scale (EDIS) tool and its effect on managing infections and reducing unplanned hospital admissions in nursing home residents. Implementation of the EDIS tool may have important implications for the healthcare economy; this will be explored in cost–benefit analyses as the work progresses.

scholarly journals Association between SARS-CoV-2 Seroprevalence in Nursing Home Staff and Resident COVID-19 Cases and Mortality: A Cross-Sectional Study

Viruses ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 43
Author(s):  
Ania Wisniak ◽  
Lakshmi Krishna Menon ◽  
Roxane Dumont ◽  
Nick Pullen ◽  
Simon Regard ◽  
...  
Keyword(s):  
Nursing Home ◽  
Nursing Homes ◽  
Correlation Coefficient ◽  
Cumulative Incidence ◽  
Nursing Home Residents ◽  
Cross Sectional Study ◽  
Sectional Study ◽  
Cross Sectional ◽  
Nursing Home Staff ◽  
Increased Risk

The burden of COVID-19 has disproportionately impacted the elderly, who are at increased risk of severe disease, hospitalization, and death. This cross-sectional study aimed to assess the association between SARS-CoV-2 seroprevalence among nursing home staff, and cumulative incidence rates of COVID-19 cases, hospitalizations, and deaths among residents. Staff seroprevalence was estimated within the SEROCoV-WORK+ study between May and September 2020 across 29 nursing homes in Geneva, Switzerland. Data on nursing home residents were obtained from the canton of Geneva for the period between March and August 2020. Associations were assessed using Spearman’s correlation coefficient and quasi-Poisson regression models. Overall, seroprevalence among staff ranged between 0 and 31.4%, with a median of 8.3%. A positive association was found between staff seroprevalence and resident cumulative incidence of COVID-19 cases (correlation coefficient R = 0.72, 95%CI 0.45–0.87; incidence rate ratio [IRR] = 1.10, 95%CI 1.07–1.17), hospitalizations (R = 0.59, 95%CI 0.25–0.80; IRR = 1.09, 95%CI 1.05–1.13), and deaths (R = 0.71, 95%CI 0.44–0.86; IRR = 1.12, 95%CI 1.07–1.18). Our results suggest that SARS-CoV-2 transmission between staff and residents may contribute to the spread of the virus within nursing homes. Awareness among nursing home professionals of their likely role in the spread of SARS-CoV-2 has the potential to increase vaccination coverage and prevent unnecessary deaths due to COVID-19.

Utility of Bone Marrow Biopsy, Bone Marrow Aspirate, Flow Cytometry, and Molecular Testing in the Clinical Staging of Lymphoma: An Institutional Experience.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 4596-4596
Author(s):  
Randall J. Dumont ◽  
Louis A.V. Fernandez ◽  
Ridas Juskevicius
Keyword(s):  
Bone Marrow ◽  
Predictive Value ◽  
Bone Marrow Aspirate ◽  
Bone Marrow Involvement ◽  
Performance Characteristics ◽  
Positive Test Result ◽  
Post Test ◽  
Test Result ◽  
Post Test Probability ◽  
Test Probability

Abstract Lymphomas are a diverse group of solid tumors of lymphoid cells that are broadly subdivided into Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL) categories. In the Western world, lymphoma is the most common hematologic malignancy. Complete and accurate staging of the patient with lymphoma is essential in determining the extent of initial disease. Bone marrow biopsy (BMB) remains the gold standard for assessing bone marrow involvement by lymphoma. It allows morphological diagnosis as well as the use of immunohistochemistry in difficult cases. At the time of BMB, other specimens are often gathered for use in ancillary investigations that can aid in diagnosis and/or staging. These investigations include bone marrow aspirate (BMA), flow cytometry (FC), and molecular studies (M) such as PCR. The objectives of this study were to evaluate the performance characteristics of BMA, FC, and M relative to BMB in lymphoma staging, to determine how frequently ancillary testing is positive for bone marrow involvement with lymphoma while BMB is negative, as well as to determine the clinical significance of this situation. Retrospective analysis was performed on 294 lymphoma cases from 1997 to 2002 at a single adult tertiary care center. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), pre-test probability (PreTP), post-test probability given a positive test result (PTP+), and post-test probability given a negative test result (PTP−) were determined. Chart review was performed to determine clinical significance of the situation when BMB is negative and one or more ancillary investigations are positive. The number of cases positive for lymphoma by BMB, BMA, M, and FC was 157,113, 109, and 111, respectively. The performance characteristics are indicated in Table I. Twelve cases in which one or more ancillary investigations were positive when BMB was negative were identified. Clinical management was not altered in these cases. In staging of lymphoma, BMB remains the gold standard for the determination of bone marrow involvement. When compared to BMB, ancillary investigations have a high specificity and PPV, but only moderate sensitivity and NPV. Ancillary bone marrow investigations appear to add little information to lymphoma staging, and may not be fiscally justified. Table I. Performance Characteristics Of Ancillary Bone Marrow Investigations In The Staging Of Lymphoma Parameter Bone Marrow Aspirate Molecular FlowCytometry Abbreviations: PPV = positive predictive value; NPV = negative predictive; PreTP = pre-test probability; PTP+ = post-test probability given a positive test result; PTP− = post-test probability given a negative test result Sensitivity 71% 64% 68% Specificity 98% 93% 96% PPV 97% 92% 95% PreTP 53% 53% 53% PTP+ 97% 92% 95% PTP− 26% 31% 28%

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