The role of physicians as medical review officers in workplace drug testing programs. In pursuit of the last nanogram.

In discussing the role of physicians in workplace drug testing programs, I focus on the recent Department of Transportation regulations that require drug testing in such regulated industries as interstate trucking, air transportation, mass transit, and the railroads. These regulations require that applicable drug testing programs employ physicians as medical review officers to evaluate positive tests that have been screened and confirmed by different techniques to determine if there is a legal medical explanation for the result. The drug testing program tests for the presence of amphetamine, cocaine, tetrahydrocannabinol, opiates, and phencyclidine. If an employee testing positive has an acceptable medical explanation, the result is to be reported as negative. Little practical advice exists for medical review officers, and they must be aware of key elements of the regulations and potential trouble spots.     

Closing the gaps in genetics legislation and policy: a report by the new york state task force on life and the law

The New York State Task Force on Life and the Law, a state bioethical policy commission, recently completed a project addressing the ethical, legal, and social concerns surrounding the predictive uses of genetic testing. Its report, Genetic Testing and Screening in the Age of Genomic Medicine, makes legislative, public policy, and practice recommendations on a host of issues. As part of this project, the Task Force reviewed the current policy and legislative landscapes related to confidentiality protections for genetic information and the use of genetic information by insurers. It also assessed requirements for informed consent to clinical genetic testing and for the use of clinical samples for genetics research. The Task Force considered gaps and unintended consequences of relevant genetic testing legislation and assessed its flexibility to address new uses of genetic testing, such as pharmacogenetic testing, and new ways of offering tests, such as multiplex testing panels. The Task Force also considered the relevance of the pleiotropic characteristic of genes for issues of informed consent to genetic testing and the confidentiality of genetic information. The Task Force's recommendations, presented here, seek to promote the appropriate uses of clinical genetic testing and research while preventing potential harms.     

Drug testing in oral fluid

Over the last decade there have been considerable developments in the use of oral fluid (saliva) for drug testing. Oral fluid can provide a quick and non-invasive specimen for drug testing. However, its collection may be thwarted by lack of available fluid due to a range of physiological factors, including drug use itself. Food and techniques designed to stimulate production of oral fluid can also affect the concentration of drugs. Current applications are mainly focused on drugs of abuse testing in employees at workplaces where drug use has safety implications, in drivers of vehicles at the roadside and in other situations where drug impairment is suspected. Testing has included alcohol (ethanol) and a range of clinical tests eg antibodies to HIV, therapeutic drugs and steroids. Its main application has been for testing for drugs of abuse such as the amphetamines, cocaine and metabolites, opioids such as morphine, methadone and heroin, and for cannabis. Oral fluid concentrations of basic drugs such as the amphetamines, cocaine and some opioids are similar or higher than those in plasma. Tetrahydrocannabinol (THC), the major species present from cannabis use, displays similar concentrations in oral fluid compared to blood in the elimination phase. However, there is significant local absorption of the drug in the oral cavity which increases the concentrations for a period after use of drug. Depot effects occur for other drugs introduced into the body that allow local absorption, such as smoking of tobacco (nicotine), cocaine, amphetamines, or use of sub-lingual buprenorphine. Screening techniques are usually an adaptation of those used in other specimens, with an emphasis on the parent drug since this is usually the dominant species present in oral fluid. Confirmatory techniques are largely based on mass spectrometry (MS) with an emphasis on Liquid Chromatography-Mass Spectrometry (LC-MS), due to low sample volumes and the low detection limits required. Drug testing outside laboratory environments has become widespread and provides presumptive results within minutes of collection of specimens. This review focuses on the developments, particularly over the last 10 years, and outlines the roles and applications of testing for drugs in oral fluid, describes the difficulties associated with this form of testing and illustrates applications of oral fluid testing for specific drugs.     

OUTLINING ETHICAL ISSUES IN NANOTECHNOLOGIES

Nanotechnologies are an expression of the human ability to control and manipulate matter on a very small scale. Their use will enable an even and constant monitoring of human organisms, in a new and perhaps less invasive way. Debates at all levels – national, European and international – have pointed out the common difficulty of giving a complete, clear definition of nanotechnologies. This is primarily due to the variety of their components, to the fact that there is not just one technology but several.
The most significant medical applications of nanotechnologies are in the diagnostic and the therapeutic fields, eg biosensors and molecular imaging, providing diagnosis and drug delivery with no invasive methods involved.
Like any other emerging field, such technologies imply new possibilities for improving health but, on the other hand, they are still at an experimental stage and therefore should be implemented under rigorous safety testing before going on general release. For this purpose, the ethical, legal and social implications (ELSI) of nanotechnologies have been elaborated by study groups, in order to develop solutions before the results of the tests are diffused into medical practice.
The aim of this paper is to define some of the ethical issues concerning biomedical applications and to evaluate whether there is a need for new or additional guidelines and regulations.     

Defining the spectrum of genome policy

Many achievements in the genome sciences have been facilitated by policies that have prioritized genome research, secured funding and raised public and health-professional awareness. Such policies should address ethical, legal and social concerns, and are as important to the scientific and commercial development of the field as the science itself. On occasion, policy issues take precedence over science, particularly when impasses are encountered or when public health or money is at stake. Here we discuss the spectrum of current issues and debates in genome policy, and how to actively engage all affected stakeholders to promote effective policy making.     

Strategy for genotoxicity testing: hazard identification and risk assessment in relation to in vitro testing

This report summarizes the proceedings of the September 9-10, 2005 meeting of the Expert Working Group on Hazard Identification and Risk Assessment in Relation to In Vitro Testing, part of an initiative on genetic toxicology. The objective of the Working Group was to develop recommendations for interpretation of results from tests commonly included in regulatory genetic toxicology test batteries, and to propose an appropriate strategy for follow-up testing when positive in vitro results were obtained in these assays. The Group noted the high frequency of positive in vitro findings in the genotoxicity test batteries with agents found not to be carcinogenic and thought not to pose a carcinogenic health hazard to humans. The Group agreed that a set of consensus principles for appropriate interpretation and follow-up testing when initial in vitro tests are positive was needed. Current differences in emphasis and policy among different regulatory agencies were recognized as a basis of this need. Using a consensus process among a balanced group of recognized international authorities from industry, government, and academia, it was agreed that a strategy based on these principles should include guidance on: (1) interpretation of initial results in the "core" test battery; (2) criteria for determining when follow-up testing is needed; (3) criteria for selecting appropriate follow-up tests; (4) definition of when the evidence is sufficient to define the mode of action and the relevance to human exposure; and (5) definition of approaches to evaluate the degree of health risk under conditions of exposure of the species of concern (generally the human). A framework for addressing these issues was discussed, and a general "decision tree" was developed that included criteria for assessing the need for further testing, selecting appropriate follow-up tests, and determining a sufficient weight of evidence to attribute a level of risk and stop testing. The discussion included case studies based on actual test results that illustrated common situations encountered, and consensus opinions were developed based on group analysis of these cases. The Working Group defined circumstances in which the pattern and magnitude of positive results was such that there was very low or no concern (e.g., non-reproducible or marginal responses), and no further testing would be needed. This included a discussion of the importance of the use of historical control data. The criteria for determining when follow-up testing is needed included factors, such as evidence of reproducibility, level of cytotoxicity at which an increased DNA damage or mutation frequency is observed, relationship of results to the historical control range of values, and total weight of evidence across assays. When the initial battery is negative, further testing might be required based on information from the published literature, structure activity considerations, or the potential for significant human metabolites not generated in the test systems. Additional testing might also be needed retrospectively when increase in tumors or evidence of pre-neoplastic change is seen. When follow-up testing is needed, it should be based on knowledge about the mode of action, based on reports in the literature or learned from the nature of the responses observed in the initial tests. The initial findings, and available information about the biochemical and pharmacological nature of the agent, are generally sufficient to conclude that the responses observed are consistent with certain molecular mechanisms and inconsistent with others. Follow-up tests should be sensitive to the types of genetic damage known to be capable of inducing the response observed initially. It was recognized that genotoxic events might arise from processes other than direct reactivity with DNA, that these mechanisms may have a non-linear, or threshold, dose-response relationship, and that in such cases it may be possible to determine an exposure level below which there is negligible concern about an effect due to human exposures. When a test result is clearly positive, consideration of relevance to human health includes whether other assays for the same endpoint support the results observed, whether the mode or mechanism of action is relevant to the human, and - most importantly - whether the effect observed is likely to occur in vivo at concentrations expected as a result of human exposure. Although general principles were agreed upon, time did not permit the development of recommendations for the selection of specific tests beyond those commonly employed in initial test batteries.     

HEART DISEASE AND SOCIAL INEQUALITY: ETHICAL ISSUES IN THE AETIOLOGY, PREVENTION AND TREATMENT OF HEART DISEASE

Heart disease is a complex condition that is a leading cause of death worldwide. It is often seen as a disease of affluence, yet is strongly associated with a gradient in socio-economic status. Its highly complex causality means that many different facets of social and economic life are implicated in its aetiology, including factors such as workplace hierarchy and agricultural policy, together with other well-known factors such as what passes for individual 'lifestyle'. The very untangling of causes for heart disease thus inevitably raises social, moral and political issues. These include the proper role of the individual and of larger social forces in its aetiology, prevention and treatment. The construction of risk factors for heart disease likewise is enmeshed with questions of distributive justice in the responsible targeting of those at risk for heart disease, a debate which has received much overt attention in the medical literature, but less attention within the ethical literature. Strategies for addressing a condition of such complex causality can be highly diverse, from pharmaceutical to social interventions, and value issues attach to the choice and presentation of such strategies. For example, prevention strategies may raise complex issues of responsibility and of judgements of what it is to 'live well'. Further ethical debate on this highly political disease would be welcome.     

Testing random effects in linear mixed‐effects models with serially correlated errors

In linear mixed‐effects models, random effects are used to capture the heterogeneity and variability between individuals due to unmeasured covariates or unknown biological differences. Testing for the need of random effects is a nonstandard problem because it requires testing on the boundary of parameter space where the asymptotic chi‐squared distribution of the classical tests such as likelihood ratio and score tests is incorrect. In the literature several tests have been proposed to overcome this difficulty, however all of these tests rely on the restrictive assumption of i.i.d. measurement errors. The presence of correlated errors, which often happens in practice, makes testing random effects much more difficult. In this paper, we propose a permutation test for random effects in the presence of serially correlated errors. The proposed test not only avoids issues with the boundary of parameter space, but also can be used for testing multiple random effects and any subset of them. Our permutation procedure includes the permutation procedure in Drikvandi, Verbeke, Khodadadi, and Partovi Nia (2013) as a special case when errors are i.i.d., though the test statistics are different. We use simulations and a real data analysis to evaluate the performance of the proposed permutation test. We have found that random slopes for linear and quadratic time effects may not be significant when measurement errors are serially correlated.     

Group screening for rare events based on incomplete block designs

Fields such as, diagnostic testing, biotherapeutics, drug development, and toxicology among others, center on the premise of searching through many specimens for a rare event. Scientists in the business of “searching for a needle in a haystack” may greatly benefit from the use of group screening design strategies. Group screening, where specimens are composited into pools with each pool being tested for the presence of the event, can be much more cost-efficient than testing each individual specimen. A number of group screening designs have been proposed in the literature. Incomplete block screening designs are described here and compared with other group screening designs. It is shown under certain conditions, that incomplete block screening designs can provide nearly a 90% cost saving compared to other group screening designs such as when prevalence is 0.001 and screening 3876 specimens with an ICB-sequential design vs. a Dorfman design. In other cases, previous group screening designs are shown to be most efficient. Overall, when prevalence is small (≤0.05) group screening designs are shown to be quite cost effective at screening a large number of specimens and in general there is no one design that is best in all situations. © 2018 American Institute of Chemical Engineers Biotechnol Progress, 35: e2770, 2019.     

Prevalence of HIV among childbearing women and women having termination of pregnancy: multidisciplinary steering group study.

OBJECTIVE--To determine the prevalence of HIV among pregnant women, in particular those whose behaviour or that of their partners put them at "low risk" of infection. DESIGN--Voluntary named or anonymous HIV testing of pregnant women during 21 months (November 1988 to July 1990). SUBJECTS AND SETTING--All women who planned to continue their pregnancy and attended clinics serving the antenatal populations of Edinburgh and Dundee. All women admitted for termination of pregnancy to gynaecology wards serving the pregnant populations of Dundee and outlying rural areas. MAIN OUTCOME MEASURES--Period prevalence of HIV antibody positivity. RESULTS--91% of antenatal clinic attenders and 97% of women having termination of pregnancy agreed to HIV testing on a named or anonymous basis. HIV period prevalences for antenatal clinic attenders and women having termination of pregnancy tested in Dundee were 0.13% and 0.85% respectively, and for antenatal clinic attenders tested in Edinburgh 0.26%. For those at "low risk" rates for antenatal clinic attenders and women having termination of pregnancy in Dundee were 0.11% and 0.13%, and for antenatal clinic attenders in Edinburgh 0.02%. In Dundee HIV prevalence among women having a termination of pregnancy (0.85%) was significantly greater than that among antenatal clinic attenders (0.13%). CONCLUSIONS--HIV infection is undoubtedly occurring among women at "low risk," and it is clear that a policy of selective testing of those at only "high risk" is inadequate for pregnant women living in areas of high prevalence such as Edinburgh and Dundee. Moreover, when studying pregnant populations in such areas there is the need to include those having a termination of pregnancy.     

Assessing the impact of lateral flow testing strategies on within-school SARS-CoV-2 transmission and absences: A modelling study

Rapid testing strategies that replace the isolation of close contacts through the use of lateral flow device tests (LFTs) have been suggested as a way of controlling SARS-CoV-2 transmission within schools that maintain low levels of pupil absences. We developed an individual-based model of a secondary school formed of exclusive year group bubbles (five year groups, with 200 pupils per year) to assess the likely impact of strategies using LFTs in secondary schools over the course of a seven-week half-term on transmission, absences, and testing volume, compared to a policy of isolating year group bubbles upon a pupil returning a positive polymerase chain reaction (PCR) test. We also considered the sensitivity of results to levels of participation in rapid testing and underlying model assumptions. While repeated testing of year group bubbles following case detection is less effective at reducing infections than a policy of isolating year group bubbles, strategies involving twice weekly mass testing can reduce infections to lower levels than would occur under year group isolation. By combining regular testing with serial contact testing or isolation, infection levels can be reduced further still. At high levels of pupil participation in lateral flow testing, strategies replacing the isolation of year group bubbles with testing substantially reduce absences, but require a high volume of testing. Our results highlight the conflict between the goals of minimising within-school transmission, minimising absences and minimising testing burden. While rapid testing strategies can reduce school transmission and absences, they may lead to a large number of daily tests.     

PROVIDER‐INITIATED HIV TESTING AND COUNSELING IN HEALTH FACILITIES – WHAT DOES THIS MEAN FOR THE HEALTH AND HUMAN RIGHTS OF PREGNANT WOMEN?

Since the introduction of drugs to prevent vertical transmission of HIV, the purpose of and approach to HIV testing of pregnant women has increasingly become an area of major controversy. In recent years, many strategies to increase the uptake of HIV testing have focused on offering HIV tests to women in pregnancy-related services. New global guidance issued by the World Health Organization (WHO) and the Joint United Nations Programme on HIV/AIDS (UNAIDS) specifically notes these services as an entry point for provider-initiated HIV testing and counseling (PITC). The guidance constitutes a useful first step towards a framework within which PITC sensitive to health, human rights and ethical concerns can be provided to pregnant women in health facilities. However, a number of issues will require further attention as implementation moves forward. It is incumbent on all those involved in the scale up of PITC to ensure that it promotes long-term connection with relevant health services and does not result simply in increased testing with no concrete benefits being accrued by the women being tested. Within health services, this will require significant attention to informed consent, pre- and post-test counseling, patient confidentiality, referrals and access to appropriate services, as well as reduction of stigma and discrimination. Beyond health services, efforts will be needed to address larger societal, legal, policy and contextual issues. The health and human rights of pregnant women must be a primary consideration in how HIV testing is implemented; they can benefit greatly from PITC but only if it is carried out appropriately.     

Group testing regression model estimation when case identification is a goal

Group testing is frequently used to reduce the costs of screening a large number of individuals for infectious diseases or other binary characteristics in small prevalence situations. In many applications, the goals include both identifying individuals as positive or negative and estimating the probability of positivity. The identification aspect leads to additional tests being performed, known as “retests”, beyond those performed for initial groups of individuals. In this paper, we investigate how regression models can be fit to estimate the probability of positivity while also incorporating the extra information from these retests. We present simulation evidence showing that significant gains in efficiency occur by incorporating retesting information, and we further examine which testing protocols are the most efficient to use. Our investigations also demonstrate that some group testing protocols can actually lead to more efficient estimates than individual testing when diagnostic tests are imperfect. The proposed methods are applied retrospectively to chlamydia screening data from the Infertility Prevention Project. We demonstrate that significant cost savings could occur through the use of particular group testing protocols.     

Hypothesis testing with the similarity index

Multilocus DNA fingerprinting methods have been used extensively to address genetic issues in wildlife populations. Hypotheses concerning population subdivision and differing levels of diversity can be addressed through the use of the similarity index (S), a band-sharing coefficient, and many researchers construct hypothesis tests with S based on the work of Lynch. It is shown in the present study, through mathematical analysis and through simulations, that estimates of the variance of a mean S based on Lynch's work are downwardly biased. An unbiased alternative is presented and mathematically justified. It is shown further, however, that even when the bias in Lynch's estimator is corrected, the estimator is highly imprecise compared with estimates based on an alternative approach such as 'parametric bootstrapping' of allele frequencies. Also discussed are permutation tests and their construction given the interdependence of Ss which share individuals. A simulation illustrates how some published misuses of these tests can lead to incorrect conclusions in hypothesis testing.     

Cost-Effectiveness of HIV Drug Resistance Testing to Inform Switching to Second Line Antiretroviral Therapy in Low Income Settings

Background

To guide future need for cheap resistance tests for use in low income settings, we assessed cost-effectiveness of drug resistance testing as part of monitoring of people on first line ART - with switching from first to second line ART being conditional on NNRTI drug resistance mutations being identified.

Methods

An individual level simulation model of HIV transmission, progression and the effect of ART which accounts for adherence and resistance development was used to compare outcomes of various potential monitoring strategies in a typical low income setting in sub-Saharan Africa. Underlying monitoring strategies considered were based on clinical disease, CD4 count or viral load. Within each we considered a strategy in which no further measures are performed, one with a viral load measure to confirm failure, and one with both a viral load measure and a resistance test. Predicted outcomes were assessed over 2015–2025 in terms of viral suppression, first line failure, switching to second line regimen, death, HIV incidence, disability-adjusted-life-years averted and costs. Potential future low costs of resistance tests ($30) were used.

Results

The most effective strategy, in terms of DALYs averted, was one using viral load monitoring without confirmation. The incremental cost-effectiveness ratio for this strategy was $2113 (the same as that for viral load monitoring with confirmation). ART monitoring strategies which involved resistance testing did not emerge as being more effective or cost effective than strategies not using it. The slightly reduced ART costs resulting from use of resistance testing, due to less use of second line regimens, was of similar magnitude to the costs of resistance tests.

Conclusion

Use of resistance testing at the time of first line failure as part of the decision whether to switch to second line therapy was not cost-effective, even though the test was assumed to be very inexpensive.     

Molecular diagnostics: hurdles for clinical implementation

In the coming years, molecular diagnostics will continue to be of critical importance to public health worldwide. It will facilitate the detection and characterization of disease, as well as monitoring of the drug response, and will assist in the identification of genetic modifiers and disease susceptibility. A wide range of molecular-based tests is available to assess DNA variation and changes in gene expression. However, there are major hurdles to overcome before the implementation of these tests in clinical laboratories, such as which test to employ, the choice of technology and equipment, and issues such as cost-effectiveness, accuracy, reproducibility, personnel training, reimbursement by third-party payers and intellectual property. At present, PCR-based testing predominates; however, alternative technologies aimed at reducing genome complexity without PCR are anticipated to gain momentum in the coming years. Furthermore, development of integrated chip devices ("lab-on-a-chip") should allow point-of-care testing and facilitate genetic readouts from single cells and molecules. Together with proteomic-based testing, these advances will improve molecular diagnostic testing and will present additional challenges for implementing such testing in health care settings.     

Estimating biomarker-based HIV incidence using prevalence data in high risk groups with missing outcomes

The novel two-step serologic sensitive/less sensitive testing algorithm for detecting recent HIV seroconversion (STARHS) provides a simple and practical method to estimate HIV-1 incidence using cross-sectional HIV seroprevalence data. STARHS has been used increasingly in epidemiologic studies. However, the uncertainty of incidence estimates using this algorithm has not been well described, especially for high risk groups or when missing data is present because a fraction of sensitive enzyme immunoassay (EIA) positive specimens are not tested by the less sensitive EIA. Ad hoc methods used in practice provide incorrect confidence limits and thus may jeopardize statistical inference. In this report, we propose maximum likelihood and Bayesian methods for correctly estimating the uncertainty in incidence estimates obtained using prevalence data with a fraction missing, and extend the methods to regression settings. Using a study of injection drug users participating in a drug detoxification program in New York city as an example, we demonstrated the impact of underestimating the uncertainty in incidence estimates using ad hoc methods. Our methods can be applied to estimate the incidence of other diseases from prevalence data using similar testing algorithms when missing data is present.