scholarly journals Adapting Lot Quality Assurance Sampling to accommodate imperfect tests: application to COVID-19 serosurveillance in Haiti

2020 ◽  
Author(s):  
Isabel Fulcher ◽  
Mary Clisbee ◽  
Wesler Lambert ◽  
Fernet Renand Leandre ◽  
Bethany Hedt-Gauthier
Keyword(s):  
Quality Assurance ◽  
Diagnostic Test ◽  
Sensitivity And Specificity ◽  
Healthcare Workers ◽  
Health Indicators ◽  
Lot Quality Assurance Sampling ◽  
Classification Errors ◽  
Antibody Tests ◽  
Imperfect Sensitivity

Abstract Background: Lot Quality Assurance Sampling (LQAS), a tool used for monitoring health indicators in low resource settings resulting in “high” or “low” classifications, assumes that determination of the trait of interest is perfect. This is often not true for diagnostic tests, with imperfect sensitivity and specificity. Here, we develop Lot Quality Assurance Sampling for Imperfect Tests (LQAS-IMP) to address this issue and apply it to a COVID-19 serosurveillance study in Haiti.Results: As part of the standard LQAS procedure, the user specifies allowable classification errors for the system, which is defined by a sample size and decision rule. We show that when an imperfect diagnostic test is used, the classification errors are larger than specified. We derive a modified procedure, LQAS-IMP, that accounts for the sensitivity and specificity of a diagnostic test to yield correct classification errors. We apply our methods to create a sampling scheme at Zanmi Lasante health facilities in Haiti to assess the prior circulation of COVID-19 among healthcare workers (HCWs) using a limited number of antibody tests. Conclusions: The LQAS-IMP procedure accounts for imperfect sensitivity and specificity in system design; if the accuracy of a test is known, the use of LQAS-IMP extends LQAS to applications for indicators that are based on laboratory tests, such as COVID-19 antibodies.

scholarly journals Adapting Lot Quality Assurance Sampling to accommodate imperfect tests: application to COVID-19 serosurveillance in Haiti

2020 ◽  
Author(s):  
Isabel R Fulcher ◽  
Mary Clisbee ◽  
Wesler Lambert ◽  
Fernet Renand Leandre ◽  
Bethany Hedt-Gauthier
Keyword(s):  
Quality Assurance ◽  
Diagnostic Test ◽  
Sensitivity And Specificity ◽  
Healthcare Workers ◽  
Health Indicators ◽  
Lot Quality Assurance Sampling ◽  
Classification Errors ◽  
Antibody Tests ◽  
Imperfect Sensitivity

Background: Lot Quality Assurance Sampling (LQAS), a tool used for monitoring health indicators in low resource settings resulting in "high" or "low" classifications, assumes that determination of the trait of interest is perfect. This is often not true for diagnostic tests, with imperfect sensitivity and specificity. Here, we develop Lot Quality Assurance Sampling for Imperfect Tests (LQAS-IMP) to address this issue and apply it to a COVID-19 serosurveillance study in Haiti. Development: As part of the standard LQAS procedure, the user specifies allowable classification errors for the system, which is defined by a sample size and decision rule. We show that when an imperfect diagnostic test is used, the classification errors are larger than specified. We derive a modified procedure, LQAS-IMP, that accounts for the sensitivity and specificity of a diagnostic test to yield correct classification errors. Application: At Zanmi Lasante health facilities in Haiti, the goal was to assess the prior circulation of COVID-19 among healthcare workers (HCWs) using a limited number of antibody tests. As the COVID-19 antibody tests were known to have imperfect diagnostic accuracy, we used the LQAS-IMP procedure to define valid systems for sampling at eleven hospitals in Haiti. Conclusions: The LQAS-IMP procedure accounts for imperfect sensitivity and specificity in system design; if the accuracy of a test is known, the use of LQAS-IMP extends LQAS to applications for indicators that are based on laboratory tests, such as COVID-19 antibodies.

scholarly journals Hand Hygiene Compliance Study at a Large Central Hospital in Vietnam

2019 ◽  
Vol 16 (4) ◽  
pp. 607 ◽  
Author(s):  
Cam Le ◽  
Erik Lehman ◽  
Thanh Nguyen ◽  
Timothy Craig
Keyword(s):  
Quality Assurance ◽  
Hand Hygiene ◽  
Healthcare Workers ◽  
Medical Center ◽  
Compliance Rate ◽  
World Health ◽  
Limiting Factors ◽  
Cultural Attitudes ◽  
Knowledge And Attitude ◽  
Hygiene Compliance

Lack of proper hand hygiene among healthcare workers has been identified as a core facilitator of hospital-acquired infections. Although the concept of hand hygiene quality assurance was introduced to Vietnam relatively recently, it has now become a national focus in an effort to improve the quality of care. Nonetheless, barriers such as resources, lack of education, and cultural norms may be limiting factors for this concept to be properly practiced. Our study aimed to assess the knowledge and attitude of healthcare workers toward hand hygiene and to identify barriers to compliance, as per the World Health Organization’s guidelines, through surveys at a large medical center in Vietnam. In addition, we aimed to evaluate the compliance rate across different hospital departments and the roles of healthcare workers through direct observation. Results showed that, in general, healthcare workers had good knowledge of hand hygiene guidelines, but not all believed in receiving reminders from patients. The barriers to compliance were identified as: limited resources, patient overcrowding, shortage of staff, allergic reactions to hand sanitizers, and lack of awareness. The overall compliance was 31%; physicians had the lowest rate of compliance at 15%, while nurses had the highest rate at 39%; internal medicine had the lowest rate at 16%, while the intensive care unit had the highest rate at 40%. In summary, it appears that addressing cultural attitudes in addition to enforcing repetitive quality assurance and assessment programs are needed to ensure adherence to safe hand washing.

scholarly journals Quality Assurance Systems in Nursing. A turning point in the world of nursing homes

2014 ◽  
Vol 5 (1) ◽  
pp. 99-108
Author(s):  
Pedro Andreo ◽  
Carmelo Gómez ◽  
Elena Carrasco ◽  
Inmaculada Martínez-Escámez ◽  
Inmaculada Alguazas ◽  
...  
Keyword(s):  
Quality Assurance ◽  
Nursing Homes ◽  
Nursing Practice ◽  
Health Indicators ◽  
General Interest ◽  
Quality Assurance System ◽  
Nursing Service ◽  
Positive Effects ◽  
Assurance System ◽  
Positive Results

Developing and trying to achieve a high quality in the service nursing personnel provide at nursing homes by means of implementing quality assurance systems is a topic of general interest nowadays. These systems have already proved to be effective in other fields. That is why the focus of this study is to analyse the most relevant effects due to the implementation of a quality assurance method based on standard UNE EN ISO 9001:2008 in the nursing service of four nursing homes. An analysis of more than 200 answers of a satisfaction survey about the nursing service at four nursing homes has been carried out. A study on the available bibliography about the results obtained after having implemented a quality assurance system in the nursing service at nursing homes has also been carried out. Very positive results can be appreciated in the daily nursing practice at nursing homes as a consequence of using a quality assurance system. Clinical practice has improved considerably as a consequence. The study shows quality assurance systems to be a useful tool at the service of nursing practice at nursing homes. Positive effects resulting from the implementation of such quality assurance systems are evident as it can be seen from satisfaction surveys and health indicators.

scholarly journals Right choice of a method for determination of cut-off values: A statistical tool for a diagnostic test

2014 ◽  
Vol 5 (3) ◽  
pp. 30-34 ◽  
Author(s):  
Balkishan Sharma ◽  
Ravikant Jain
Keyword(s):  
Logistic Regression ◽  
Discriminant Analysis ◽  
Diagnostic Test ◽  
Roc Curve ◽  
Traditional Method ◽  
Statistical Technique ◽  
Curve Analysis ◽  
Operating Characteristics ◽  
Roc Curve Analysis

Objective: The clinical diagnostic tests are generally used to identify the presence of a disease. The cutoff value of a diagnostic test should be chosen to maximize the advantage that accrues from testing a population of human and others. When a diagnostic test is to be used in a clinical condition, there may be an opportunity to improve the test by changing the cutoff value. To enhance the accuracy of diagnosis is to develop new tests by using a proper statistical technique with optimum sensitivity and specificity. Method: Mean±2SD method, Logistic Regression Analysis, Receivers Operating Characteristics (ROC) curve analysis and Discriminant Analysis (DA) have been discussed with their respective applications. Results: The study highlighted some important methods to determine the cutoff points for a diagnostic test. The traditional method is to identify the cut-off values is Mean±2SD method. Logistic Regression Analysis, Receivers Operating Characteristics (ROC) curve analysis and Discriminant Analysis (DA) have been proved to be beneficial statistical tools for determination of cut-off points.Conclusion: There may be an opportunity to improve the test by changing the cut-off value with the help of a correctly identified statistical technique in a clinical condition when a diagnostic test is to be used. The traditional method is to identify the cut-off values is Mean ± 2SD method. It was evidenced in certain conditions that logistic regression is found to be a good predictor and the validity of the same can be confirmed by identifying the area under the ROC curve. Abbreviations: ROC-Receiver operating characteristics and DA-Discriminant Analysis. Asian Journal of Medical Science, Volume-5(3) 2014: 30-34 http://dx.doi.org/10.3126/ajms.v5i3.9296      

scholarly journals A new highly sensitive and specific overnight combined screening and diagnostic test for primary aldosteronism

2016 ◽  
Vol 175 (1) ◽  
pp. 21-28 ◽  
Author(s):  
Vaios Tsiavos ◽  
Athina Markou ◽  
Labrini Papanastasiou ◽  
Theodora Kounadi ◽  
Ioannis I Androulakis ◽  
...  
Keyword(s):  
Diagnostic Test ◽  
Sensitivity And Specificity ◽  
Primary Aldosteronism ◽  
Low Cost ◽  
Confirmatory Test ◽  
Outpatient Basis ◽  
Endocrine Hypertension ◽  
Serum Aldosterone ◽  
Highly Sensitive ◽  
Aldosterone To Renin Ratio

Context Primary aldosteronism (PA) is the most common cause of endocrine hypertension that is diagnosed following a two-step process: an initial screening test, based on the serum aldosterone-to-renin ratio (ARR), followed by a relatively laborious and time-consuming confirmatory test to document autonomous aldosterone (ALD) secretion. Objective The aim of this study is to develop a simple overnight test for the early and definite diagnosis of PA. Patients and methods Totally, 148 hypertensive patients underwent a fludrocortisone–dexamethasone suppression test (FDST) and the new overnight diagnostic test (DCVT) using pharmaceutical RAAS (renin–angiotensin–aldosterone system) blockade with dexamethasone, captopril and valsartan. Results Of the 148 patients, 45 were diagnosed as having PA and they all normalized their elevated blood pressure (BP) after administration of spironolactone or eplerenone. The remaining 103 patients were considered as having essential hypertension and served as controls. Using ROC analysis, the estimated sensitivity and specificity were 91 and 100%, respectively, for the post-FDST ARR, whereas 98% and 89% and 100% and 82% for the post-DCVT ARR and post-DCVT ALD, respectively, with selected cutoffs of 0.32ng/dL/μU/mL and 3ng/dL respectively. However, considering these cutoffs simultaneously, the estimated sensitivity and specificity were 98 and 100% respectively. Applying these cutoffs, the diagnosis of PA was confirmed in 44 (98%) of the 45 patients who were considered to have the disease. Conclusions In this study, a highly sensitive and specific, low-cost, rapid, safe, and easy-to-perform diagnostic test (DCVT) for PA is described, which could be utilized on an outpatient basis potentially substituting conventional laborious testing.

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.

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