Modeling Correlations Between Diagnostic Tests in Efficacy Studies with an Imperfect Reference Test

1997 ◽  
pp. 363-371
Author(s):  
Yinsheng Qu ◽  
Alula Hagdu
Keyword(s):  
Diagnostic Tests ◽  
Reference Test ◽  
Efficacy Studies

scholarly journals Diagnostic performance evaluation of hepatitis B e antigen rapid diagnostic tests in Malawi

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Alexander J. Stockdale ◽  
Niza M. Silungwe ◽  
Isaac Thom Shawa ◽  
Benno Kreuels ◽  
Melita A. Gordon ◽  
...  
Keyword(s):  
Hepatitis B ◽  
Diagnostic Tests ◽  
Antiviral Treatment ◽  
Rapid Diagnostic Tests ◽  
Hbv Dna ◽  
Sub Saharan Africa ◽  
World Health ◽  
Hepatitis B E Antigen ◽  
Reference Test ◽  
Hospitalised Patients

Abstract Background The World Health Organization (WHO) has targeted a reduction in viral hepatitis-related mortality by 65% and incidence by 90% by 2030, necessitating enhanced hepatitis B treatment and prevention programmes in low- and middle-income countries. Hepatitis B e antigen (HBeAg) status is used in the assessment of eligibility for antiviral treatment and for prevention of mother-to-child transmission (PMTCT). Accordingly, the WHO has classified HBeAg rapid diagnostic tests (RDTs) as essential medical devices. Methods We assessed the performance characteristics of three commercially available HBeAg RDTs (SD Bioline, Alere, South Africa; Creative Diagnostics, USA; and Biopanda Reagents, UK) in two hepatitis B surface antigen-positive cohorts in Blantyre, Malawi: participants of a community study (n = 100) and hospitalised patients with cirrhosis or hepatocellular carcinoma (n = 94). Two investigators, blinded to the reference test result, independently assessed each assay. We used an enzyme-linked immunoassay (Monolisa HBeAg, Bio-Rad, France) as a reference test and quantified HBeAg concentration using dilutions of the WHO HBeAg standard. We related the findings to HBV DNA levels, and evaluated treatment eligibility using the TREAT-B score. Results Among 194 HBsAg positive patients, median age was 37 years, 42% were femaleand 26% were HIV co-infected. HBeAg prevalence was 47/194 (24%). The three RDTs showed diagnostic sensitivity of 28% (95% CI 16–43), 53% (38–68) and 72% (57–84) and specificity of 96–100% for detection of HBeAg. Overall inter-rater agreement κ statistic was high at 0.9–1.0. Sensitivity for identifying patients at the threshold where antiviral treatment is recommended for PMTCT, with HBV DNA > 200,000 IU/ml (39/194; 20%), was 22, 49 and 54% respectively. Using the RDTs in place of the reference HBeAg assay resulted in 3/43 (9%), 5/43 (12%) and 8/43 (19%) of patients meeting the TREAT-B treatment criteria being misclassified as ineligible for treatment. A relationship between HBeAg concentration and HBeAg detection by RDT was observed. A minimum HBeAg concentration of 2.2–3.1 log10IU/ml was required to yield a reactive RDT. Conclusions Commercially available HBeAg RDTs lack sufficient sensitivity to accurately classify hepatitis B patients in Malawi. This has implications for hepatitis B public health programs in sub-Saharan Africa. Alternative diagnostic assays are recommended.

scholarly journals Evaluation of Triage Tests When Existing Test Capacity Is Constrained: Application to Rapid Diagnostic Testing in COVID-19

2021 ◽  
pp. 0272989X2110141
Author(s):  
Janet Bouttell ◽  
Neil Hawkins
Keyword(s):  
Diagnostic Tests ◽  
Diagnostic Testing ◽  
High Accuracy ◽  
Cost Utility ◽  
Polymerase Chain Reaction Test ◽  
Lower Sensitivity ◽  
Reference Test ◽  
Rapid Diagnostic Testing ◽  
Lower Accuracy ◽  
Triage Test

Objectives A triage test is used to determine which patients will undergo an existing or “reference” test. This article explores the potential value of using triage tests before reference tests when the capacity of the reference test is constrained. Methods We developed a simple model with inputs: prevalence, sensitivity, specificity, and reference test capacity. We included a case study of rapid diagnostic tests for SARS-CoV-2 antigens used as triage tests before a reference polymerase chain reaction test. Performance data were obtained from an evaluation performed by an academic center on 425 samples from testing centers in the United Kingdom and Germany. Results When reference test capacity is constrained, the use of a triage test leads to a relative expansion of the population tested and cases identified; both are higher with a high-specificity triage test. When reference test capacity is not constrained, the potential advantages of introducing a triage test can be assessed using a standard cost-utility framework, balancing the utility of the reduction in the number of reference tests required against the disutility of missed cases associated with the use of a lower-sensitivity triage test. In the constrained case, the advantage of a triage testing strategy in terms of population covered and cases identified is reduced as the prevalence increases. In the unconstrained case, the reduction in reference tests required is reduced and the number of cases missed increase as the prevalence rises. Conclusion When the availability of the reference test is constrained, tests added in a triage position do not need high levels of accuracy to increase the number of cases diagnosed. This has implications in many disease areas, including COVID-19. Twitter: Lower-accuracy #COVID19 tests can still be useful, according to a new article, “Evaluation of Triage Tests When Existing Test Capacity Is Constrained: Application to Rapid Diagnostic Testing in COVID-19,” co-authored by @janetbouttell & @NeilSHawkins @HEHTAGlasgow @MedDecMak There is much emphasis on high-accuracy #COVID19 tests, but lower-accuracy tests have their place, according to a new study on triage tests when test capacity is constrained, co-authored by @janetbouttell & @NeilSHawkins @HEHTAGlasgow @MedDecMak A new study, co-authored by @janetbouttell & @NeilSHawkins @HEHTAGlasgow, has shown that when there is limited capacity of high-accuracy #COVID19 diagnostic tests, triage testing strategies can increase the population covered and the number of #COVID19 cases identified. @MedDecMak

scholarly journals Assessing field performance of ultrasensitive rapid diagnostic tests for malaria: a systematic review and meta-analysis

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Celestin Danwang ◽  
Fati Kirakoya-Samadoulougou ◽  
Sekou Samadoulougou
Keyword(s):  
Sensitivity And Specificity ◽  
Diagnostic Tests ◽  
Clinical Presentation ◽  
Meta Analysis ◽  
Random Effect ◽  
Random Effect Model ◽  
Rapid Diagnostic Tests ◽  
Field Conditions ◽  
Reference Test ◽  
Malaria Rapid Diagnostic Tests

Abstract Background To overcome the limitations of conventional malaria rapid diagnostic tests (cRDTs) in diagnosing malaria in patients with low parasitaemia, ultrasensitive malaria rapid diagnostic tests (uRDTs) have recently been developed, with promising results under laboratory conditions. The current study is the first meta-analysis comparing the overall sensitivity, and specificity of newly developed ultrasensitive Plasmodium falciparum malaria RDT (Alere™ Ultra-sensitive Malaria Ag P. falciparum RDT) with the cRDT conducted in the same field conditions. Methods PubMed, EMBASE, Cochrane infectious diseases group specialized register, and African Journals Online (AJOL) were searched up to 20th April 2021. Studies with enough data to compute sensitivity and specificity of uRDT and cRDT were retrieved. A random-effect model for meta-analysis was used to obtain the pooled sensitivity and specificity. Results Overall, 15 data sets from 14 studies were included in the meta-analysis. The overall sensitivity of the Alere™ ultra-sensitive Malaria Ag P. falciparum RDT regardless of the reference test and the clinical presentation of participants, was 55.5% (95% confidence interval [CI]: 45.5; 65.0), while the sensitivity regardless of the reference test and the clinical presentation of participants, was 42.9% (95% CI: 31.5; 55.2) for the cRDT performed in the same field conditions. When PCR was used as reference test, the sensitivity of uRDT was 60.4% (95% CI: 50.8; 69.2), while the sensitivity was 49.4% (95% CI: 38.2; 60.6) for the cRDT. The pooled specificity of uRDT regardless of the reference test and the clinical presentation of participants was 98.6% (95% CI: 97.1; 99.4), and the pooled specificity of cRDT regardless of the reference test and the clinical presentation of participants was 99.3% (95% CI: 98.1; 99.7). When PCR was used as reference test the specificity of uRDT and cRDT was 97.5% (95% CI: 94.1; 98.9) and 98.2% (95% CI: 95.5; 99.3). Regardless of the reference test used, the sensitivity of Alere™ Ultra-sensitive Malaria Ag P. falciparum RDT in symptomatic patients was 72.1% (95%CI: 67.4; 76.4), while sensitivity of cRDT was 67.4% (95%CI: 57.6; 75.9). Conclusion Findings of the meta-analysis show that Alere™ Ultra-sensitive Malaria Ag P. falciparum RDT compared to cRDT performed in the same field conditions has higher sensitivity but lower specificity although the difference is not statistically significant.

Images of Aging in the Psychotherapeutic Context

GeroPsych ◽  
2015 ◽  
Vol 28 (2) ◽  
pp. 47-55 ◽  
Author(s):  
Eva-Marie Kessler ◽  
Catherine E. Bowen
Keyword(s):  
Old Age ◽  
Diagnostic Tests ◽  
Aging Process ◽  
Developmental Psychology ◽  
Mental Representations ◽  
Later Life ◽  
Future Research ◽  
Psychotherapeutic Process ◽  
Images Of Aging ◽  
Client Communication

Both psychotherapists and their clients have mental representations of old age and the aging process. In this conceptual review, we draw on available research from gerontology, social and developmental psychology, and communication science to consider how these “images of aging” may affect the psychotherapeutic process with older clients. On the basis of selected empirical findings we hypothesize that such images may affect the pathways to psychotherapy in later life, therapist-client communication, client performance on diagnostic tests as well as how therapists select and apply a therapeutic method. We posit that interventions to help both older clients and therapists to reflect on their own images of aging may increase the likelihood of successful treatment. We conclude by making suggestions for future research.

The present state of aspirin and clopidogrel resistance

2009 ◽  
Vol 29 (03) ◽  
pp. 285-290 ◽  
Author(s):  
K. E. Guyer
Keyword(s):  
Diagnostic Tests ◽  
Arterial Thrombosis ◽  
Cardiovascular Events ◽  
Treatment Success ◽  
Antiplatelet Agents ◽  
Antiplatelet Drug ◽  
Coronary Syndrome ◽  
Testing Method ◽  
Pharmacological Response ◽  
Platelet Physiology

SummaryAntiplatelet therapy has demonstrated significant clinical benefit in the treatment of acute coronary syndrome. However, as with any treatment strategy it has been unable to prevent all cardiovascular events. This is far from surprising when considering the complexity of arterial thrombosis and more specifically platelet physiology. This lack of treatment success has provoked the introduction of various diagnostic tests and testing platforms with the intent of guiding and optimizing clinical treatment. Such tests have resulted in the generation of clinical data that suggest suboptimal response to antiplatelet agents such as aspirin and clopidogrel.In the case of both aspirin and clopidogrel, this suboptimal response has been termed resistance. Drug resistance would imply a lack of pharmacological response that has not been specifically investigated in many of the clinical studies performed to date. Rather, the term resistance has been used to describe various facets of platelet activation and aggregation relative to the testing method. Many of these measured parameters are not addressed in the therapeutic intent of the antiplatelet drug in question.

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