Bioenzyme-nanoenzyme-chromogen all-in-one test strip for convenient and sensitive detection of malathion in water environment

The presence of pesticide residues in aquatic environments poses a significant threat to both aquatic ecosystems and human health. The presence of these residues can result in significant harm to aquatic ecosystems and can negatively impact the health of aquatic organisms. Consequently, this issue requires urgent attention and effective measures to mitigate its impact. However, developing sensitive and rapid detection methods remains a challenge. In this study, an all-in-one test strip, which integrated bioenzymes, nanoenzymes, and a chromogen, was developed in combination with an enzyme labeling instrument for a highly sensitive and convenient sensing of malathion residues. The oxidase activity of heme chloride (Hemin) in the strip can catalyze the oxidation of H2O2 and 3,3',5,5'-tetramethylbenzidine (TMB) to produce a blue-colored oxide. Simultaneously, the alkaline phosphatase (ALP) present in the strip can break down l-ascorbic acid-2-phosphate to produce ascorbic acid (AA). This AA then acts to reduce the oxidized form of TMB, turning it into a colorless substance and leading to the disappearance of its fluorescent signal. In the presence of a pesticide, the activity of ALP is inhibited and formation of AA is blocked, thereby preventing the reduction of oxidized TMB and producing a colored signal. According to this principle, the integrated test strip detected the target pesticide with high performance as per the optical density value determined via an enzyme marker. The detection limit of the test strip was 0.209 ng/mL with good sensitivity. The method was used for detecting malathion in actual river water samples, and the recoveries were in the range of 93.53 %-96.87 %. The newly devised technique effectively identified malathion in samples of natural water. This research has introduced a novel approach for the precise and convenient surveillance of pesticide remnants. Additionally, these discoveries could inspire the advancement of proficient multi-enzyme detection systems.

Real world outcomes of distributing Lucira Check-It® COVID self-tests in Ontario, Canada: the GetaKit COVID study

BACKGROUND

In Ontario, Canada we developed and implemented an online screening algorithm for the distribution of HIV self-tests, known as GetaKit. During the COVID pandemic, we adapted the GetaKit algorithm to screen for COVID based on population and infection data and distributed COVID rt-LAMP self-tests (using the Lucira Check-It®) to eligible participants.

METHODS

GetaKit/COVID was a prospective observational study that occurred over a 7-month period from September 2021 to April 2022. All potential participants completed an online registration and risk assessment, including demographic information, COVID symptoms and risk factors, and vaccination status. Bivariate comparisons were performed for three outcomes: results reporting status, vaccination status, and COVID diagnosis status. Data were analysed using Chi-Square for categorial covariates and Independent Samples T-Test and Mann-Whitney U test for continuous covariates. Bivariate logistic regression models were applied to examine associations between the covariates and outcomes.

RESULTS

During the study period, we distributed 6469 COVID self-tests to 4160 eligible participants; 46% identified as Black, Indigenous or a Person of Colour (BIPOC). Nearly 70% of participants reported their COVID self-test results; 304 of which were positive. Overall, 91% also reported being vaccinated against COVID. Statistical analysis found living with five or fewer people, having tested for COVID previously, and being fully vaccinated were positive factors in results reporting. For COVID vaccination, people from large urban centers, who identified their ethnicity as white, and who reported previous COVID testing were more likely to be fully vaccinated. Finally, being identified as a contact of someone who had tested positive for COVID and the presence of COVID-related symptoms were found to be positive factors in diagnosis.

CONCLUSIONS

While most participants who accessed this service were vaccinated against COVID and the majority of diagnoses were identified in participants who had symptoms of, or an exposure to, COVID, our program was able to appropriately link participants to recommended follow-up based on reported risks and results. These findings highlight the utility of online screening algorithms to provide health services, particularly for persons with historical barriers to healthcare access, such as BIPOC or lower-income groups.

Clinical Utility Validation of an Automated Ultrarapid Gene Fusion Assay for NSCLC

Introduction

Gene rearrangements are frequent oncologic drivers in NSCLC, and many are suitable for treatment with Food and Drug Administration-approved or experimental targeted therapies. We evaluated the accuracy, specimen acceptance profile, and limits of detection of a rapid fusion assay (Idylla GeneFusion Assay), a commercially available ultrarapid molecular assay, for its clinical utility.

Methods

A collection of 97 specimens which had previously undergone next-generation sequencing testing were analyzed using the rapid fusion assay. Accuracy was evaluated by sensitivity and specificity compared with the next-generation sequencing results. The performance characteristics were tested by using a variety of different clinically relevant specimen types. Limits of detection were assessed by evaluating different input of tumor percentage and material amount.

Results

The rapid fusion assay was found to have 100% sensitivity in detecting fusions of ALK, ROS1, RET, NTRK1, and MET exon 14 skipping and 83% sensitivity for NTRK2/3 fusions. There were 100% specificity in detecting fusions of ROS1, RET, NTRK2/3, and MET exon 14 skipping and 98% specificity for ALK. Testing was successful with formalin-fixed paraffin-embedded biopsy and surgical tissues, cell blocks from fine-needle aspiration and pleural fluid (down to 5% tumor content, 18 mm2 tissue scraped), cytology smears (≥300 cells), and previously extracted RNA (minimal 20 ng).

Conclusions

The rapid fusion assay is quick, accurate, and versatile, allowing reliable detection of ALK, ROS1, RET fusions, and MET exon 14 skipping in NSCLC, and NTRK fusions. Rapid molecular testing may expedite treatment with appropriate targeted therapies.

Validation of the NeuMoDx™ SARS-CoV-2 assay with COPAN eNAT® and E&O Viral PCR Sample Solution collection media types in comparison with other validated SARS-CoV-2 RNA assays

OBJECTIVES

This study aimed to confirm NeuMoDx™ SARS-CoV-2 assay (NeuMoDx assay) functionality using off-label collection media, determine assay performance versus other SARS-CoV-2 RNA assays, and assess any cross-reactivity with other respiratory viruses (human coronavirus NL63, influenza, and respiratory syncytial virus).

METHODS

Nasopharyngeal swab samples in off-label collection media and external quality assessment (EQA) samples were dual-tested, first using either the RealStar® SARS-CoV-2 reverse transcriptase polymerase chain reaction assay or the QIAstat-Dx® Respiratory SARS-CoV-2 Panel and then using the NeuMoDx assay. Samples found to be positive for respiratory viruses and negative for SARS-CoV-2 were then tested using the NeuMoDx assay to assess cross-reactivity.

RESULTS

Overall, 274 samples (244 patient and 30 EQA samples) were dual-tested; 154 were SARS-CoV-2 positive and 120 were negative. No false-positive or false-negative results were identified, regardless of collection medium used. The NeuMoDx assay sensitivity was 100% (95% confidence interval [CI] 97.63-100.00) and the specificity was 100% (95% CI 96.97-100.00). The assay did not exhibit any cross-reactivity with other respiratory viruses.

CONCLUSION

The NeuMoDx assay demonstrated high sensitivity and specificity on a platform well-suited for fully automated SARS-CoV-2 testing.

Who is accessing community lateral flow device testing and why? Characteristics and motivations of individuals participating in COVID-19 community testing in two English local authority areas

Background

Antigen testing using lateral flow devices (LFDs) plays an important role in the management of the novel coronavirus pandemic of 2019 (COVID-19) by rapidly identifying individuals who are asymptomatically carrying high levels of the virus. By January 2021, LFD community testing sites were set up across English local authority areas to support the management and containment of regional COVID-19 cases, initially targeting essential workers unable to work from home during the national lockdown. This study aimed to examine the characteristics and motivations of individuals accessing community LFD testing across two local authority areas (LAAs) in the South West of England.

Methods

Data were collected as part of a service evaluation from December 22^nd 2020 until March 15^th 2021 for two LAAs. Demographic and postcode data were collected from an online test appointment booking platform and the National Health Service testing service online system, with data accessed from Public Health England. An online survey was sent to individuals who made a testing appointment at an LAA1 site using the online booking platform, consisting of 12 questions to collect data on individual’s motivations for and experiences of testing.

Results

Data were available for individuals who completed 12,516 tests in LAA1 and 12,327 tests in LAA2. Most individuals who engaged with testing were female, working age, white, and worked as early years or education staff, health and social care staff, and supermarket or food production staff. 1249 individuals completed the survey with 60% of respondents reported getting tested for work-related reasons. Individuals first heard about LFD testing through various channels including work, media, and word of mouth, and decided to get tested based on the ease and convenience of testing, workplace communications, and to identify asymptomatic cases to help stop the spread. Most tests were completed by individuals living in less deprived areas based on national deciles of deprivation.

Conclusions

While national and local COVID-19 testing strategies have evolved, community and personal LFD testing remains a crucial pillar of the testing strategy. Future studies should collect quantitative and qualitative data from residents to most effectively shape testing offers based on the needs and preferences of their population.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-12986-4.

Diagnostic accuracy of a rapid diagnostic test for the early detection of COVID-19

OBJECTIVES

This study was undertaken to evaluate the diagnostic performance of the BinaxNOW COVID-19 Ag Card rapid antigen assay (Abbott; Chicago, IL, USA) in the detection of COVID-19 infection compared to the reference standard of PCR testing.

METHODS

We evaluated the BinaxNOW COVID-19 Ag Card rapid antigen assay relative to a standard reference PCR test. We tested 3810 nasal swabs from symptomatic and asymptomatic adults undergoing surveillance COVID-19 testing at Howard University using one swab for each nostril. One swab was tested using the rapid antigen assay and the other using the PCR test.

RESULTS

The sensitivity of the BinaxNOW COVID-19 Ag Card rapid antigen assay was 91.84% (95% confidence interval (CI): 80.40-97.73%) and the specificity was 99.95% (95% CI: 99.81-99.99%). The range of Ct values for the N gene was 10.74-34.90 (M = 26.88, SD=4.86). Fourteen (28.6%) samples had an N gene Ct value > 30. The average N gene Ct value for rapid test negative (i.e. false negative) samples was 31.92.

CONCLUSIONS

The sensitivity of the test in our symptomatic and asymptomatic cohort was lower than the manufacturer's reported sensitivity in a symptomatic cohort (97.1%). Despite their relatively lower sensitivity (especially in asymptomatic individuals), rapid tests have undeniable benefits (i.e., ease of use and rapid results) that make them a helpful tool in the control of the SARS-CoV-2 pandemic. Given the diagnostic accuracy of these tests as evidenced by this study, rapid tests can be thoughtfully employed in situations where swift results are critical.

Rapid Hygiene Assay Sensitive to Cumulative Adenylate Homologues Exhibits Equal or Higher Frequencies of Soil Contamination Detection than Assay Limited to ATP Detection

ABSTRACT

Based upon regulatory and food industry-driven food safety standards, there is a need for rapid, accurate methods for assessing sanitary conditions. A commonly used assay is based on the assessment of the biochemical molecule adenosine triphosphate (ATP). A more recent assay, the total adenylate homologue-based (AXP) assay, targets the cumulative presence of ATP and its dephosphorylated homologues, adenosine diphosphate and adenosine monophosphate. Yet there is little information that compares the practical performance of these two assays. This work examined these two assay types with a comparative study in a grade A dairy foods processing plant and a licensed and inspected meat processing facility. A total of 1,920 concomitant analyses were conducted with main variables of assay type, processing facility type, and hygiene zone category. Statistical process control methodology was used to calculate 95% confidence control limits; data beyond those limits were considered contamination events. Results demonstrated that overall, the AXP assay detected contamination events approximately two times more often than the assay based on ATP only. This increase in the rate of contamination event detection was especially prevalent in the meat processing facility, where across all hygienic zones, there were 38 versus 85 contaminations events detected for the ATP and AXP assays, respectively. Across hygiene zones, the AXP data displayed either an equal or an increased incidence of soil detection compared with data from the ATP assay. This study provides applied evidence that assays solely dependent on ATP concentrations are less able to detect soil contaminants under conditions that favor ATP dephosphorylation reactions.

HIGHLIGHTS

SARS-CoV-2 rapid antigen testing for departing passengers at Vancouver International Airport

Here, we show that point-of-care rapid antigen testing for COVID-19 is feasible to implement in the departure areas of a major airports for same-day travelers and effective in ruling out possible carriers of SARS-CoV-2 in asymptomatic air travelers. This strategy may help to reduce the spread of COVID-19 via air travel.

A low-cost and portable near-infrared spectrometer using open-source multivariate data analysis software for rapid discriminatory quality assessment of medroxyprogesterone acetate injectables

Medroxyprogesterone acetate (MPA) injectable suspensions are used by millions of women for family planning and hormonal therapy. Falsified or substandard medications may result in a health risk for consumers. Near-infrared spectroscopy (NIR) has previously been applied as a means of non-destructive and rapid screening of product quality compliance. These methods offer advantages but can be logistically and cost prohibitive for field use in resource limited areas. Here, a handheld spectrometer (900-1700 nm) with open-sourced software is used to evaluate vials of MPA from three suppliers (N = 227 vials) and verified by a benchtop UV-VIS-NIR (350-2500 nm) with licensed software. Multivariate data analysis assesses the spectral signatures of samples and builds a discriminant classification method based on Mahalanobis distances calculated from a principal component analysis scores. The handheld device paired with open-source software resulted in a product discrimination accuracy of 100% (verified by benchtop UV-VIS-NIR and chemical testing data) as well indicating that the low-cost field portable device is suitable for rapidly assessing samples in resource limited areas for consistency of manufacturing and sourcing.

Clinical utility of a rapid 'on-demand' laboratory-based SARS-CoV-2 diagnostic testing service in an acute hospital setting admitting COVID-19 patients

Background

With the onset of the COVID-19 pandemic in 2020, hospital clinical teams have realised that there is a need for a rapid, accurate testing facility that will allow them to move patients quickly into isolation rooms or specific COVID-19 cohort wards as soon as possible after admission.

Methods

Starting from July 2020, PCR-based test platforms, which could test 4–8 samples in parallel with turnaround (sample-to-result) times of 50–80 min, were placed in a satellite laboratory. This laboratory was on the same floor and within walking distance to the acute respiratory admissions ward. It was staffed by a team of three mid-Band 4 staff that split a 0700–2200 h-work day, 7 days a week, with 2 senior supervisors. Urgent sample testing was decided upon by the clinical teams and requested by phone. The test results were entered manually in real-time as they became available, and sent electronically to the requesting ward teams.

Results

The daily/monthly PCR positive test numbers approximately followed the local and national UK trend in COVID-19 case numbers, with the daily case numbers being reflective of the November and December 2020 surges. Test results were used to rapidly segregate positive patients into dedicated COVID-19 ward areas to minimise risk of potential nosocomial transmission in crowded waiting areas. Testing capacity was sufficient to include cases with uncertain diagnosis likely to require hospital admission. Following completion of other admission processes, based on these rapid test results, patients were allocated to dedicated COVID-19 positive or negative cohort wards.

Conclusions

This rapid testing facility reduced unnecessary ‘length-of-stay’ in a busy acute respiratory ward. In the current absence of a treatment for mild-to-moderate COVID-19, on which patients could be discharged home to complete, the rapid test facility has become a successful aid to patient flow and reduced exposure and nosocomial transmission.

pyPOCQuant - A tool to automatically quantify Point-Of-Care Tests from images

Lateral flow Point-Of-Care Tests (POCTs) are a valuable tool for rapidly detecting pathogens and the associated immune response in humans and animals. In the context of the SARS-CoV-2 pandemic, they offer rapid on-site diagnostics and can relieve centralized laboratory testing sites, thus freeing resources that can be focused on especially vulnerable groups. However, visual interpretation of the POCT test lines is subjective, error prone and only qualitative. Here we present pyPOCQuant, an open-source tool implemented in Python 3 that can robustly and reproducibly analyze POCTs from digital images and return an unbiased and quantitative measurement of the POCT test lines.

Accuracy of four lateral flow immunoassays for anti SARS-CoV-2 antibodies: a head-to-head comparative study

BACKGROUND

SARS-CoV-2 antibody tests are used for population surveillance and might have a future role in individual risk assessment. Lateral flow immunoassays (LFIAs) can deliver results rapidly and at scale, but have widely varying accuracy.

METHODS

In a laboratory setting, we performed head-to-head comparisons of four LFIAs: the Rapid Test Consortium's AbC-19TM Rapid Test, OrientGene COVID IgG/IgM Rapid Test Cassette, SureScreen COVID-19 Rapid Test Cassette, and Biomerica COVID-19 IgG/IgM Rapid Test. We analysed blood samples from 2,847 key workers and 1,995 pre-pandemic blood donors with all four devices.

FINDINGS

We observed a clear trade-off between sensitivity and specificity: the IgG band of the SureScreen device and the AbC-19TM device had higher specificities but OrientGene and Biomerica higher sensitivities. Based on analysis of pre-pandemic samples, SureScreen IgG band had the highest specificity (98.9%, 95% confidence interval 98.3 to 99.3%), which translated to the highest positive predictive value across any pre-test probability: for example, 95.1% (95% uncertainty interval 92.6, 96.8%) at 20% pre-test probability. All four devices showed higher sensitivity at higher antibody concentrations ("spectrum effects"), but the extent of this varied by device.

INTERPRETATION

The estimates of sensitivity and specificity can be used to adjust for test error rates when using these devices to estimate the prevalence of antibody. If tests were used to determine whether an individual has SARS-CoV-2 antibodies, in an example scenario in which 20% of individuals have antibodies we estimate around 5% of positive results on the most specific device would be false positives.

FUNDING

Public Health England.

Diagnostic accuracy of loop-mediated isothermal amplification coupled to nanopore sequencing (LamPORE) for the detection of SARS-CoV-2 infection at scale in symptomatic and asymptomatic populations

Objectives

Rapid, high throughput diagnostics are a valuable tool, allowing the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in populations so as to identify and isolate people with asymptomatic and symptomatic infections. Reagent shortages and restricted access to high throughput testing solutions have limited the effectiveness of conventional assays such as quantitative RT-PCR (RT-qPCR), particularly throughout the first months of the coronavirus disease 2019 pandemic. We investigated the use of LamPORE, where loop-mediated isothermal amplification (LAMP) is coupled to nanopore sequencing technology, for the detection of SARS-CoV-2 in symptomatic and asymptomatic populations.

Methods

In an asymptomatic prospective cohort, for 3 weeks in September 2020, health-care workers across four sites (Birmingham, Southampton, Basingstoke and Manchester) self-swabbed with nasopharyngeal swabs weekly and supplied a saliva specimen daily. These samples were tested for SARS-CoV-2 RNA using the Oxford Nanopore LamPORE system and a reference RT-qPCR assay on extracted sample RNA. A second retrospective cohort of 848 patients with influenza-like illness from March 2020 to June 2020 were similarly tested from nasopharyngeal swabs.

Results

In the asymptomatic cohort a total of 1200 participants supplied 23 427 samples (3966 swab, 19 461 saliva) over a 3-week period. The incidence of SARS-CoV-2 detection using LamPORE was 0.95%. Diagnostic sensitivity and specificity of LamPORE was >99.5% (decreasing to approximately 98% when clustered estimation was used) in both swab and saliva asymptomatic samples when compared with the reference RT-qPCR test. In the retrospective symptomatic cohort, the incidence was 13.4% and the sensitivity and specificity were 100%.

Conclusions

LamPORE is a highly accurate methodology for the detection of SARS-CoV-2 in both symptomatic and asymptomatic population settings and can be used as an alternative to RT-qPCR.

Impact of early detection and vaccination strategy in COVID-19 eradication program in Jakarta, Indonesia

OBJECTIVE

Several essential factors have played a crucial role in the spreading mechanism of COVID-19 (Coronavirus disease 2019) in the human population. These factors include undetected cases, asymptomatic cases, and several non-pharmaceutical interventions. Because of the rapid spread of COVID-19 worldwide, understanding the significance of these factors is crucial in determining whether COVID-19 will be eradicated or persist in the population. Hence, in this study, we establish a new mathematical model to predict the spread of COVID-19 considering mentioned factors.

RESULTS

Infection detection and vaccination have the potential to eradicate COVID-19 from Jakarta. From the sensitivity analysis, we find that rapid testing is crucial in reducing the basic reproduction number when COVID-19 is endemic in the population rather than contact trace. Furthermore, our results indicate that a vaccination strategy has the potential to relax social distancing rules, while maintaining the basic reproduction number at the minimum possible, and also eradicate COVID-19 from the population with a higher vaccination rate. In conclusion, our model proposed a mathematical model that can be used by Jakarta's government to relax social distancing policy by relying on future COVID-19 vaccine potential.

Near-point-of-care assay with a visual readout for detection of HIV-1 drug resistance mutations: A proof-of-concept study

Human immunodeficiency virus (HIV) infection is a chronic disease that can be treated with antiretroviral (ARV) therapy. However, the success of this treatment has been jeopardized by the emergence of HIV infections resistant to ARV drugs. In low-to middle-income countries (LMICs), where transmission of resistant viruses has increased over the past decade, there is an urgent need to improve access to HIV drug resistance testing. Here, we present a proof-of-concept study of a rapid and simple molecular method to detect two major mutations (K103 N, Y181C) conferring resistance to first-line nonnucleoside reverse transcriptase inhibitor regimens. Our near-point-of-care (near-POC) diagnostic test, combining a sequence-specific primer extension and a lateral flow DNA microarray strip, allows visual detection of HIV drug resistance mutations (DRM) in a short turnaround time (4 h 30). The assay has a limit of detection of 100 copies of plasmid DNA and has a higher sensitivity than standard Sanger sequencing. The analytical performance was assessed by use of 16 plasma samples from individuals living with HIV-1 and results demonstrated the specificity and the sensitivity of this approach for multiplex detection of the two DRMs in a single test. Furthermore, this near-POC assay could be easily taylored to detect either new DRMs or DRM of from various HIV clades and might be useful for pre-therapy screening in LMICs with high levels of transmitted drug resistance.

Variation of quantified infection rates of mixed samples to enhance rapid testing during an epidemic

Rapid testing of appropriate samples from patients suspected for a disease during an epidemic, such as the current Coronavirus outbreak, is of a great importance for disease management and control. We propose a method to enhance processing large amounts of collected samples. The method is based on mixing samples in testing tubes (pooling) in a specific configuration, as opposed to testing single samples in each tube, and recognise infected samples from variations of the total infection rates in each tube. To illustrate the efficiency of the suggested method, we carry out numerical tests for actual scenarios under various test conditions. Applying the proposed method allows testing many more patients using the same number of testing tubes, where all positives are identified with no false negatives, and no need for independent testing, and the effective testing time can be reduced drastically even when the uncertainty in the test is relatively high.

Evaluation of three rapid lateral flow antigen detection tests for the diagnosis of SARS-CoV-2 infection

INTRODUCTION

The COVID-19 pandemic has led to high demand of diagnostic tools. Rapid antigen detection tests have been developed and many have received regulatory acceptance such as CE IVD or FDA markings. Their performance needs to be carefully assessed.

MATERIALS AND METHODS

158 positive and 40 negative retrospective samples collected in saline and analyzed by a laboratory-developed RT-PCR test were used to evaluate Sofia (Quidel), Standard Q (SD Biosensor), and Panbio™ (Abbott) rapid antigen detection tests (RADTs). A subset of the specimens was subjected to virus culture.

RESULTS

The specificity of all RADTs was 100 % and the sensitivity and percent agreement was 80 % and 85 % for Sofia, 81 % and 85 % for Standard Q, and 83 % and 86 % for Panbio™, respectively. All three RADTs evaluated in this study reached a more than 90 % sensitivity for samples with a high viral load as estimated from the low Ct (Cycle threshold) values in the reference RT-PCR. Virus culture was successful in 80 % of specimens with a Ct value <25.

CONCLUSIONS

As expected, the RADTs were less sensitive than RT-PCR. However, they benefit from the speed and ease of testing, and lower price as compared to RT-PCR. Repeated testing in appropriate settings may improve the overall performance.

Analyzing the impact of the media campaign and rapid testing for COVID-19 as an optimal control problem in East Java, Indonesia

Without any vaccine or medical intervention to cure the infected individual from COVID-19, the non-pharmaceutical intervention become the most reasonable intervention against the spread of COVID-19. In this paper, we proposed a deterministic model governed by a system of nonlinear differential equations which consider the intervention of media campaign to increase human awareness, and rapid testing to track the undetected cases in the field. Analysis of the autonomous model shows the existence of transcritical bifurcation at a basic reproduction number equal to one. We estimate our parameter using the incidence data from East Java, Indonesia. Using these parameters, we analyze the sensitivity of the parameters in determining the size of the basic reproduction number. An optimal control problem which transforms media campaign and rapid testing as a time-dependent control was conducted also in this article. Cost-effectiveness analysis using the Infection averted ratio (IAR) and the Average cost-effectiveness ratio (ACER) conducted to analyze the best strategies to eradicate COVID-19 spread. We observe that the combination of the media campaign and rapid testing as time-dependent interventions reduces the number of an infected individual significantly and also minimizes the economic burden due to these strategies in East Java.

Rapid point-of-care detection of SARS-CoV-2 using reverse transcription loop-mediated isothermal amplification (RT-LAMP)

Background

Fast, reliable and easy to handle methods are required to facilitate urgently needed point-of-care testing (POCT) in the current coronavirus pandemic. Life-threatening severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly spread all over the world, infecting more than 33,500,000 people and killing over 1 million of them as of October 2020. Infected individuals without any symptoms might still transfer the virus to others underlining the extraordinary transmissibility of this new coronavirus. In order to identify early infections effectively, treat patients on time and control disease spreading, rapid, accurate and onsite testing methods are urgently required.

Results

Here we report the development of a loop-mediated isothermal amplification (LAMP) based method to detect SARS-CoV-2 genes ORF8 and N directly from pharyngeal swab samples. The established reverse transcription LAMP (RT-LAMP) assay detects SARS-CoV-2 directly from pharyngeal swab samples without previous time-consuming and laborious RNA extraction. The assay is sensitive and highly specific for SARS-CoV-2 detection, showing no cross reactivity when tested on 20 other respiratory pathogens. The assay is 12 times faster and 10 times cheaper than routine reverse transcription real-time polymerase chain reaction, depending on the assay used.

Conclusion

The fast and easy to handle RT-LAMP assay amplifying specifically the genomic regions ORF8 and N of SARS-CoV-2 is ideally suited for POCT at e.g. railway stations, airports or hospitals. Given the current pandemic situation, rapid, cost efficient and onsite methods like the here presented RT-LAMP assay are urgently needed to contain the viral spread.

Dietary bioaccumulation potential of silver nanomaterials compared to silver nitrate in wistar rats using an ex vivo gut sac technique

Chronic dietary bioaccumulation tests with rodents are required for new substances, including engineered nanomaterials (ENMs), in order to provide information on the potential hazards to human health. However, screening tools are needed to manage the diversity of ENMs and alternative methods are desirable with respect to animal welfare. Here, an ex vivo gut sac method was used to estimate the dietary bioaccumulation potential of silver nanomaterials. The entire gastrointestinal tract (except the caecum) was removed and filled with a gut saline containing 1 mg L^-1 of Ag as either AgNO₃, silver nanoparticles (Ag NPs) or silver sulphide nanoparticles (Ag₂S NPs), and compared to controls with no added Ag. The gut sacs were incubated for 4 h, rinsed to remove excess media, and the total Ag determined in the mucosa and muscularis. There was no detected Ag in the control treatments. Within the Ag treatments, 1.4-22% of the exposure dose was associated with the tissues and serosal saline. Within the mucosa of the AgNO₃ treatment, the highest Ag concentration was associated with the intestinal regions (3639-7087 ng g^-1) compared to the stomach (639 ± 128 ng g^-1). This pattern was also observed in the Ag NP and Ag₂S NP treatments, but there was no significant differences between any Ag treatments for the mucosa. However, differences between treatments were observed in the muscularis concentration. For example, both the Ag NP (907 ± 284 ng g ^-1) and Ag₂S NP (1482 ± 668 ng g^-1) treatments were significantly lower compared to the AgNO₃ treatment (2514 ± 267 ng g^-1). The duodenum demonstrated serosal accumulation in both the AgNO₃ (~10 ng mL^-1) and Ag NP (~3 ng mL^-1) treatments. The duodenum showed some of the highest Ag accumulation with 41, 61 and 57% of the total Ag in the mucosa compared to the muscularis for the AgNO₃, Ag NP and Ag₂S NP treatments, respectively. In conclusion, the ex vivo gut sac method demonstrates the uptake of Ag in all Ag treatments, with the duodenum the site of highest accumulation. Based on the serosal saline accumulation, the ranked order of accumulation is AgNO₃ > Ag NPs > Ag₂S NPs.

Distributed Microbiology Testing: Bringing Infectious Disease Diagnostics to Point of Care

We discuss the current practice of point-of-care diagnostics in infectious diseases as methods transition from antigen-based to molecular, and beyond simple molecular to the next generations of point-of-care testing methods. We evaluate the role of point-of-care at different sites of care and describe and evaluate trends likely to be driven by advances in molecular methodology, emerging biomarkers, and informatics. We describe strengths, weaknesses, opportunities, and threats to the development of point-of-care diagnostics in the near (1-10 years) and more distant (10-20 years) future.

Clinical evaluation of a SARS-CoV-2 RT-PCR assay on a fully automated system for rapid on-demand testing in the hospital setting

BACKGROUND

The ongoing SARS-CoV-2 pandemic presents a unique challenge for diagnostic laboratories around the world. Automation of workflows in molecular diagnostics is instrumental for coping with the large number of tests ordered by clinicians, as well as providing fast-tracked rapid testing for highly urgent cases. In this study we evaluated a SARS-CoV-2 LDT for the NeuMoDx 96 system, a fully automated device performing extraction and real-time PCR.

METHODS

A publicly available SARS-CoV-2 RT-PCR assay was adapted for the automated system. Analytical performance was evaluated using in-vitro transcribed RNA and clinical performance was compared to the cobas 6800-based reference assay within the lab.

RESULTS

The Envelope (E) Gene-LDT displayed good analytical performance with an LoD of 95.55 cp/mL and no false positives during evaluation of cross-reactivity. A total of 176 patient samples were tested with both the E-Gene-LDT and the reference assay. Positive and negative agreement were 100 % and 99.2 % respectively. Invalid-rate was 6.3 %.

CONCLUSION

The E-Gene-LDT showed analytical and clinical performance comparable to the cobas6800-based reference assay. Due to its random-access workflow concept and rapid time-to-result of about 80 min, the system is very well suited for providing fast-tracked SARS-CoV-2 diagnostics for urgent clinical samples in the hospital setting.

A predictive tool for identification of SARS-CoV-2 PCR-negative emergency department patients using routine test results

Background

Testing for COVID-19 remains limited in the United States and across the world. Poor allocation of limited testing resources leads to misutilization of health system resources, which complementary rapid testing tools could ameliorate.

Objective

To predict SARS-CoV-2 PCR positivity based on complete blood count components and patient sex.

Study design

A retrospective case-control design for collection of data and a logistic regression prediction model was used. Participants were emergency department patients > 18 years old who had concurrent complete blood counts and SARS-CoV-2 PCR testing. 33 confirmed SARS-CoV-2 PCR positive and 357 negative patients at Stanford Health Care were used for model training. Validation cohorts consisted of emergency department patients > 18 years old who had concurrent complete blood counts and SARS-CoV-2 PCR testing in Northern California (41 PCR positive, 495 PCR negative), Seattle, Washington (40 PCR positive, 306 PCR negative), Chicago, Illinois (245 PCR positive, 1015 PCR negative), and South Korea (9 PCR positive, 236 PCR negative).

Results

A decision support tool that utilizes components of complete blood count and patient sex for prediction of SARS-CoV-2 PCR positivity demonstrated a C-statistic of 78 %, an optimized sensitivity of 93 %, and generalizability to other emergency department populations. By restricting PCR testing to predicted positive patients in a hypothetical scenario of 1000 patients requiring testing but testing resources limited to 60 % of patients, this tool would allow a 33 % increase in properly allocated resources.

Conclusions

A prediction tool based on complete blood count results can better allocate SARS-CoV-2 testing and other health care resources such as personal protective equipment during a pandemic surge.

Testing the repatriated for SARS-Cov2: Should laboratory-based quarantine replace traditional quarantine?

Background

An ongoing epidemic of respiratory diseases caused by a novel coronavirus (COVID 2019, SARS-CoV2) started in Wuhan, Hubei, in China at the end of December 2019. The French government decided to repatriate the 337 French nationals living in Wuhan and place them in quarantine in their home country. We decided to test them all for SARS-Cov2 twice in order to reduce anxiety among the population and decision-makers.

Methods

We investigated the presence of SARS-CoV-19 in asymptomatic carriers by testing all repatriated patients within the first 24 h of their arrival in France and at day 5. Viral RNA was extracted from pooled nasal and oropharyngeal swab fluids or sputum in the absence of nasal/oropharyngeal swabs. Detection of SARS-CoV-2 RNA was then carried out using several real-time reverse transcription (RT)-PCR assays.

Results

We tested 337 passengers at day 0 and day 5. All the tests for SARS-CoV2 were negative. By optimising the sampling process, sending samples sequentially and reducing the time-scale for biological analysis, we were able to test the samples within 5 h (including sampling, shipment and biological tests).

Conclusion

Optimising our procedures reduces anxiety and reassures the population and decision makers.

Assessment of readiness to transition from antenatal HIV surveillance surveys to PMTCT programme data-based HIV surveillance in South Africa: The 2017 Antenatal Sentinel HIV Survey

OBJECTIVE

South Africa has used antenatal HIV surveys for HIV surveillance in pregnant women since 1990. We assessed South Africa's readiness to transition to programme data based antenatal HIV surveillance with respect to PMTCT uptake, accuracy of point-of-care rapid testing (RT) and selection bias with using programme data in the context of the 2017 antenatal HIV survey.

METHODS

Between 1 October and 15 November 2017, the national survey was conducted in 1,595 public antenatal facilities selected using stratified multistage cluster sampling method. Results of point-of-care RT were obtained from medical records. Blood samples were taken from eligible pregnant women and tested for HIV using immunoassays (IA) in the laboratory. Descriptive statistics were used to report on: PMTCT uptake; agreement between HIV point-of-care RT and laboratory-based HIV-1 IA; and selection bias associated with using programme data for surveillance.

RESULTS

PMTCT HIV testing uptake was high (99.8%). The positive percent agreement (PPA) between RT and IA was lower than the World Health Organization (WHO) benchmark (97.6%) at 96.3% (95% confidence interval (CI): 95.9%-96.6%). The negative percent agreement was above the WHO benchmark (99.5%), at 99.7% (95% CI: 99.6%-99.7%) nationally. PPA markedly varied by province (92.9%-98.3%). Selection bias due to exclusion of participants with no RT results was within the recommended threshold at 0.3%.

CONCLUSION

For the three components assessed, South Africa was close to meeting the WHO standard for transitioning to routine RT data for antenatal HIV surveillance. The wide variations in PPA across provinces should be addressed.

Collaborative Antimicrobial Stewardship: Working with Microbiology

There have been tremendous advances in methodologies available for detection and identification of organisms causing infections. Providers can now obtain identification results and antimicrobial susceptibility results in a shorter period of time. However, declining health care resources highlight the importance of selecting the right test at the right time to maximize diagnostic benefits. Therefore, the role of the antimicrobial stewardship team in the clinical microbiology laboratory has expanded to include diagnostic stewardship and provision of guidance on test selection for diagnosis and management of infection. This review focuses on the experience of our group in collaborative stewardship, emphasizing successes and challenges.

Rapid Sample Preparation and LAMP for Phytoplasma Detection

Loop-mediated isothermal AMPlification (LAMP) allows the rapid detection of pathogens by polymerase-mediated amplification of target nucleic acid sequences at a single incubation temperature. LAMP can be combined with very simple sample preparation/crude DNA extraction protocols, allowing the method to be used away from the laboratory for in-field detection. Equally, these benefits can also be leveraged to provide a rapid method suited to high-throughput diagnostic laboratories. In this chapter we described a crude DNA extraction protocol suitable for use in the field and provide a protocol for real-time detection using LAMP.

Microbial identification from faces and urine in one step by two-photon excitation assay technique

Two-photon excitation fluorometry (TPX) is a separation-free bioaffinity assay technique which enables accurate diagnostic testing in microvolumes. The technology is currently commercially applied in an automated mariPOC® test system for rapid phenotypic multi-microbe detection of pathogen antigens. The first TPX applications for diagnostics were intended for respiratory infection testing from nasopharyngeal and oropharyngeal samples. Feces and urine are more complex sample matrices and contain substances that may interfere with immunoassay binding or fluorescence detection. Our objective was to study the suitability of these complex matrices in the TPX technique. As expected, feces and urine elevated fluorescence levels but the methodology has the unique property of compensating for matrix effects. Compensation allows reliable separation of specific fluorescence from the fluorescence caused by the matrix. The studied clinical samples did not contain immunoassay inhibitors. The results suggest that the methodology is robust and may provide reliable testing of feces and urine samples with high accuracy.

Evaluation of hibergene loop-mediated isothermal amplification assay for detection of group B streptococcus in recto-vaginal swabs: a prospective diagnostic accuracy study

OBJECTIVES

To prospectively evaluate HiberGene's loop-mediated isothermal amplification (LAMP) assay for detection of group B streptococcus (GBS) in maternal recto-vaginal swabs and compare it with enrichment culture.

METHODS

Following ethical approval and informed written consent, two low vaginal and rectal swabs were obtained from 400 pregnant women. One swab was tested for GBS using the rapid LAMP assay (index test), the second swab was tested using enrichment culture (reference standard). Antimicrobial susceptibility testing was performed according to EUCAST guidelines.

RESULTS

There were 376 concordant results, 20 discordant and four invalid LAMP results. Among discordant results, six were LAMP negative/culture positive and 14 were LAMP positive/culture negative. The sensitivity was 92.2%, specificity 95.6%, positive predictive value 83.5% and negative predictive value 98.1%. The prevalence of GBS carriage was 19.25% (77/400). Forty-eight of 77 GBS-positive women were colonized vaginally (62.3%) and 70 were colonized rectally (90.9%). Erythromycin resistance was 22.4% (17/76) and clindamycin resistance was 17.1% (13/76).

CONCLUSIONS

The LAMP assay is a rapid and simple test with results available in approximately 1 h compared with 48 h for culture. The test has good sensitivity and specificity compared with enrichment culture. This test can be used for rapid antenatal GBS screening.

Sustainability of Statewide Rapid HIV Testing in Labor and Delivery

The objective was to assess sustainability of a statewide program of HIV rapid testing (RT) for pregnant women presenting for delivery with unknown HIV status. This is a population-based retrospective cohort study of women delivered in Illinois hospitals (2012-15). Deidentified data on RT metrics from state-mandated surveillance reports were compared using descriptive statistics and non-parametric tests of trend. Over 95% of the 608,408 women delivered had documented HIV status at presentation. The rate of undocumented HIV status rose from 4.19 to 4.75% (p < 0.001). However, overall 99.60% of women with undocumented status appropriately received RT and the proportion who did not receive RT declined (p = 0.003). The number of neonates discharged with unknown HIV status declined (p = 0.011). RT identified 23 new HIV diagnoses, representing 4.62% of maternal HIV diagnoses. In conclusion, statewide perinatal HIV RT resulted in nearly 100% of Illinois mother-infant dyads with known HIV status. Sustained RT completion represents an important prevention safety net.

Pilot Evaluation of the Ability of Men Who Have Sex with Men to Self-Administer Rapid HIV Tests, Prepare Dried Blood Spot Cards, and Interpret Test Results, Atlanta, Georgia, 2013

In the United States, an estimated 67% of new HIV diagnoses are among men who have sex with men (MSM), however 25% of HIV-positive MSM in the 2014 National HIV Behavioral Surveillance Survey were unaware of their infection. HIV self-testing (HIVST) with rapid diagnostic tests (RDTs) may facilitate access to HIV testing. We evaluated the ability of 22 MSM to conduct two HIV RDTs (OraQuick ^® In-Home HIV Test and a home-use prototype of Sure Check ^® HIV 1/2 Assay), interpret sample images of test results, and collect a dried blood spot (DBS) specimen. While some participants did not follow every direction, most participants were able to conduct HIVST and correctly interpret their results. Interpretation of panels of RDT images was especially difficult when the "control" line was missing, and 27% of DBS cards produced were rated as of bad quality. Modifications to the DBS instructions were necessary prior to evaluating the performance of these tests in real-world settings.

Acceptability and HIV Prevention Benefits of a Peer-Based Model of Rapid Point of Care HIV Testing for Australian Gay, Bisexual and Other Men Who Have Sex with Men

Frequent HIV testing among gay, bisexual and other men who have sex with men (GBM) is a strategic priority for HIV prevention in Australia. To overcome barriers to testing in conventional clinical services, Australia recently introduced peer HIV rapid point of care (RPOC) testing services for GBM. This mixed methods evaluation describes client acceptability and HIV prevention benefits of a peer HIV testing model. Most aspects of the service model were overwhelmingly acceptable to clients. Two-thirds of survey participants reported preferring testing with peers rather than doctors or nurses and over half reported learning something new about reducing HIV risk. Focus group findings suggested peer-delivered HIV RPOC testing reduced stigma-related barriers to frequent testing and provided novel opportunities for GBM to openly discuss HIV prevention and sexual practices, enhancing their HIV risk-reduction knowledge. Analysis of survey data suggested knowledge transfer occurred particularly among younger and less gay community-attached GBM.

The Unyvero P55 'sample-in, answer-out' pneumonia assay: A performance evaluation

Background

O’Neill’s recent Review on Antimicrobial Resistance expressed the view that by 2020 high-income countries should make it mandatory to support antimicrobial prescribing with rapid diagnostic evidence whenever possible.

Methods

Routine microbiology diagnosis of 95 respiratory specimens from patients with severe infection were compared with those generated by the Unyvero P55 test, which detects 20 pathogens and 19 antimicrobial resistance markers. Supplementary molecular testing for antimicrobial resistance genes, comprehensive culture methodology and 16S rRNA sequencing were performed.

Results

Unyvero P55 produced 85 valid results, 67% of which were concordant with those from the routine laboratory. Unyvero P55 identified more potential pathogens per specimen than routine culture (1.34 vs. 0.47 per specimen). Independent verification using 16S rRNA sequencing and culture (n = 10) corroborated 58% of additional detections compared to routine microbiology. Overall the average sensitivity for organism detection by Unyvero P55 was 88.8% and specificity was 94.9%. While Unyvero P55 detected more antimicrobial resistance markers than routine culture, some instances of phenotypic resistance were missed.

Conclusions

The Unyvero P55 is a rapid pathogen detection test for lower respiratory specimens, which identifies a larger number of pathogens than routine microbiology. The clinical significance of these additional organisms is yet to be determined. Further studies are required to determine the effect of the test in practise on antimicrobial prescribing and patient outcomes.

Increasing HIV testing among hard-to-reach groups: examination of RAPID, a community-based testing service in Queensland, Australia

Background

The success of ‘treatment as prevention’ (TasP) to control HIV relies on the uptake of testing across priority population groups. Innovative strategies including; rapid HIV testing (RHT) in community and outreach settings, engaging peer service providers, and not requiring disclosure of sexual history have been designed to increase access. This paper reports on the implementation of ‘RAPID’, a community-based testing program in Queensland, Australia that employs these strategies to increase access to testing.

Methods

Service data, including client registration forms and a satisfaction survey from all clients attending RAPID between August 2014 and July 2015 were analysed.

Results

In 2014/2015 1,199 people attended RAPID to receive a free HIV test. The majority were urban-based gay men. 17.1% were first-time testers and 20.1% of participants were not eligible to access Medicare, Australia’s universal health care scheme.

Conclusions

RAPID’s evidence-based strategies appear to facilitate access to HIV testing, particularly among those who have never tested before; however the implications for the ongoing treatment and care of people ineligible for Medicare, who test positive to HIV warrants careful consideration.

Electronic supplementary material

The online version of this article (doi:10.1186/s12913-017-2249-5) contains supplementary material, which is available to authorized users.

Colorimetric aptasensor for progesterone detection based on surfactant-induced aggregation of gold nanoparticles

This paper proposes an aptasensor for progesterone (P4) detection in human serum and urine based on the aggregating behavior of gold nanoparticles (AuNPs) controlled by the interactions among P4-binding aptamer, target P4 and cationic surfactant hexadecyltrimethylammonium bromide (CTAB). The aptamer can form an aptamer-P4 complex with P4, leaving CTAB free to aggregate AuNPs in this aptasensor. Thus, the sensing solution will turn from red (520 nm) to blue (650 nm) in the presence of P4 because P4 aptamers are used up firstly owing to the formation of an aptamer-P4 complex, leaving CTAB free to aggregate AuNPs. However, in the absence of P4, CTAB combines with aptamers so that AuNPs still remain dispersed. Therefore, this assay makes it possible to detect P4 not only by absorbance measurement but also through naked eyes. By monitoring the variation of absorbance and color, a CTAB-induced colorimetric assay for P4 detection was established with a detection limit of 0.89 nM. Besides, the absorbance ratio A650/A520 has a linear correlation with the P4 concentration of 0.89-500 nM. Due to the excellent recoveries in serum and urine, this biosensor has great potential with respect to the visual and instrumental detection of P4 in biological fluids.

Rapid detection of Clostridium difficile toxins and laboratory diagnosis of Clostridium difficile infections

BACKGROUND

Clostridium difficile is an anaerobic, spore-forming and Gram-positive bacillus. It is the major cause of antibiotic-associated diarrhea prevailing in hospital settings. The morbidity and mortality of C. difficile infection (CDI) has increased significantly due to the emergence of hypervirulent strains. Because of the poor clinical different between CDI and other causes of hospital-acquired diarrhea, laboratory test for C. difficile is an important intervention for diagnosis of CDI.

OBJECTIVE

Laboratory tests for CDI can broadly detect either the organisms or its toxins. Currently, several laboratory tests are used for diagnosis of CDI, including toxigenic culture, glutamate dehydrogenase detection, nucleic acid amplification testing, cell cytotoxicity assay, and enzyme immunoassay towards toxin A and/or B. This review focuses on the rapid testing of C. difficile toxins and currently available methods for diagnosis of CDI, giving an overview of the role that the toxins rapid detecting plays in clinical diagnosis of CDI.

Loop-mediated isothermal amplification (LAMP) for the rapid detection of Mycoplasma genitalium

Mycoplasma genitalium is a sexually transmissible, pathogenic bacterium and a significant cause of nongonococcal urethritis in both men and women. Due to the difficulty of the culture of M. genitalium from clinical samples, the laboratory diagnosis of M. genitalium infection is almost exclusively carried out using nucleic acid amplification tests. Loop-mediated isothermal amplification (LAMP) is a novel nucleic acid amplification technology, utilising a set of 4 primers specific to 6 distinct regions of the target DNA sequence, in order to amplify target DNA in a highly specific and rapid manner. A LAMP assay was designed to the pdhD gene of M. genitalium, and the limit of detection of the assay was determined as 10 fg of M. genitalium genomic DNA, equating to ~16 copies of the M. genitalium genome, which was equally sensitive as a gold standard 16S rRNA polymerase chain reaction assay.

Syphilis testing in antenatal care: Policies and practices among laboratories in the Americas

Objective:

To asses laboratory syphilis testing policies and practices among laboratories in the Americas.

Methods:

Laboratory directors or designees from PAHO member countries were invited to participate in a structured, electronically-delivered survey between March and August, 2014. Data on syphilis tests, algorithms, and quality control (QC) practices were analyzed, focusing on laboratories receiving specimens from antenatal clinics (ANCs).

Results:

Surveys were completed by 69 laboratories representing 30 (86%) countries. Participating laboratories included 36 (52%) national or regional reference labs and 33 (48%) lower-level laboratories. Most (94%) were public sector facilities and 71% reported existence of a national algorithm for syphilis testing in pregnancy, usually involving both treponemal and non-treponemal testing (72%). Less than half (41%) used rapid syphilis tests (RSTs); and only seven laboratories representing five countries reported RSTs were included in the national algorithm for pregnant women. Most (83%) laboratories serving ANCs reported using some type of QC system; 68% of laboratories reported participation in external QC. Only 36% of laboratories reported data to national/local surveillance. Half of all laboratories serving ANC settings reported a stockout of one or more essential supplies during the previous year (median duration, 30 days).

Conclusion:

Updating laboratory algorithms, improving testing standards, integrating data into existing surveillance, and improved procurement and distribution of commodities may be needed to ensure elimination of MTCT of syphilis in the Americas.

Cost-effectiveness analysis of the Xpert MTB/RIF assay for rapid diagnosis of suspected tuberculosis in an intermediate burden area

OBJECTIVES

We examined, from a Hong Kong healthcare providers' perspective, the cost-effectiveness of rapid diagnosis with Xpert in patients hospitalized for suspected active pulmonary tuberculosis (PTB).

METHODS

A decision tree was designed to simulate outcomes of three diagnostic assessment strategies in adult patients hospitalized for suspected active PTB: conventional approach, sputum smear plus Xpert for acid-fast bacilli (AFB) smear-negative, and a single sputum Xpert test. Model inputs were derived from the literature. Outcome measures were direct medical cost, one-year mortality rate, quality-adjusted life-years (QALYs) and incremental cost per QALY (ICER).

RESULTS

In the base-case analysis, Xpert was more effective with higher QALYs gained and a lower mortality rate when compared with smear plus Xpert by an ICER of USD99. A conventional diagnostic approach was the least preferred option with the highest cost, lowest QALYs gained and highest mortality rate. Sensitivity analysis showed that Xpert would be the most cost-effective option if the sensitivity of sputum AFB smear microscopy was ≤74%. The probabilities of Xpert, smear plus Xpert and a conventional approach to be cost-effective were 94.5%, 5.5% and 0%, respectively, in 10,000 Monte Carlo simulations.

CONCLUSIONS

The Xpert sputum test appears to be a highly cost-effective diagnostic strategy for patients with suspected active PTB in an intermediate burden area like Hong Kong.

Evaluation of novel second-generation RSV and influenza rapid tests at the point of care

Acute respiratory infections represent common pediatric emergencies. Infection control warrants immediate and accurate diagnoses. In the past, first-generation respiratory syncytial virus (RSV) rapid tests (strip tests) have shown suboptimal sensitivities. In 2013, the Food and Drug Administration licensed a second-generation RSV rapid test providing user-independent readouts (SOFIA™-RSV) using automated fluorescence assay technology known to yield superior results with influenza rapid testing. We are reporting the first point-of-care evaluation of the SOFIA™-RSV rapid test. In the Charité Influenza-Like Disease Cohort, 686 nasopharyngeal samples were tested in parallel with SOFIA™-RSV and SOFIA™-Influenza A+B. Compared to real-time PCR, SOFIA™-RSV sensitivities/specificities were 78.6%/93.9%, respectively (SOFIA™-Influenza A: 80.6%/99.3%). Performance was greatest in patients below 2 years of age with a test sensitivity of 81.8%. RSV sensitivities were highest (85%) in the first 2 days of illness and with nasopharyngeal compared to nasal swabs (P=0.055, McNemar's test). Second-generation RSV and influenza rapid testing provides highly accurate results facilitating timely patient cohortation and management.

Evaluation of a rapid antigen detection point-of-care test for respiratory syncytial virus and influenza in a pediatric hospitalized population in the Netherlands

This pilot study evaluates the diagnostic performance of Sofia RSV Fluorescent Immunoassay Analyzer (FIA) and Sofia Influenza A + B FIA for rapid detection of respiratory syncytial virus and influenza A and B. Sofia had a lower-than-expected sensitivity for all viruses and a high rate of false-positive results for influenza B virus.

Determining the relative sensitivity of benthic diatoms to atrazine using rapid toxicity testing: a novel method

Herbicides pose a potential threat to aquatic ecosystems, especially to phototrophic organisms such as benthic diatoms. Benthic diatoms may be a valuable indicator of the toxic impacts of herbicides in aquatic systems. However, this requires information on the herbicide sensitivity of a wide range of freshwater benthic diatom taxa. Unfortunately this information is only available for a limited number of species as current methods of developing new algae toxicity tests on individual taxa are lengthy and costly. To address this issue, we developed a new rapid toxicity test method to test natural benthic communities, from which the relative herbicide sensitivity of many individual taxa can be derived. This involved the collection of natural benthic communities from rocks in situ, which were placed directly into laboratory toxicity tests. Sensitivity data for several diatom genera in a 48 hour exposure toxicity test were produced, without the need for cultures or multiple site visits. After exposure to the highest treatment of atrazine (500 μg L(-1)) there were significant declines of healthy cells in the most sensitive genera: Gomphonema declined by 74%, Amphora by 62%, Cymbella by 54% and Ulnaria by 34% compared to control levels. In contrast, the genera, Eunotia, Achnanthidium and Navicula, had no statistically significant decline in cell health. This method can identify the diatom taxa most at risk of herbicide toxicity within the natural benthic diatom community. The rapid toxicity testing method presented is a simple and effective method to obtain sensitivity data for multiple taxa within a natural benthic diatom community in a relatively short period of time.

Performance of a rapid multi-analyte 2-photon excitation assay in children with acute respiratory infection

The purpose of this study is to evaluate the diagnostic performance of the novel 2-photon excitation-based mariPOC© Assay (ArcDia Laboratories, Turku, Finland) for antigen detection of respiratory viruses versus real-time polymerase chain reaction (PCR). The mariPOC Assay and 2 multiplex real-time PCR techniques were performed on nasopharyngeal samples from pediatric patients with suspicion of acute respiratory infection admitted to a children's hospital in Spain during October 2011 to January 2013. A total of 233 samples were studied. Sensitivities and specificities (95% confidence interval) of the mariPOC Assay were for respiratory syncytial virus (RSV), 78.4% (69.7-85.6) and 99.2% (96.3-100.0); influenza virus (IFV) A, 66.7% (26.2-94.0) and 99.6% (97.9-100.0); IFV-B, 63.6% (33.6-87.2) and 100.0% (98.7-100.0); human metapneumovirus (hMPV), 60.0% (34.5-81.9) and 100.0% (98.6-100.0); adenovirus (ADV), 12.5% (0.6-48.0) and 100.0% (98.7-100.0), respectively. The mariPOC Assay is a highly specific method for simultaneous detection of 8 respiratory viruses but has sensitivities that range from moderately high for RSV to moderate for IFV and hMPV and low for ADV.

Breast cancer in women at high risk: the role of rapid genetic testing for BRCA1 and -2 mutations and the consequences for treatment strategies

Specific clinical questions rise when patients, who are diagnosed with breast cancer, are at risk of carrying a mutation in BRCA1 and -2 gene due to a strong family history or young age at diagnosis. These questions concern topics such as 1. Timing of genetic counseling and testing, 2. Choices to be made for BRCA1 or -2 mutation carriers in local treatment, contralateral treatment, (neo)adjuvant systemic therapy, and 3. The psychological effects of rapid testing. The knowledge of the genetic status might have several advantages for the patient in treatment planning, such as the choice whether or not to undergo mastectomy and/or prophylactic contralateral mastectomy. The increased risk of developing a second breast cancer in the ipsilateral breast in mutation carriers, is only slightly higher after primary cancer treatment, than in the general population. Prophylactic contralateral mastectomy provides a substantial reduction of contralateral breast cancer, although only a small breast cancer specific survival benefit. Patients should be enrolled in clinical trials to investigate (neo)-adjuvant drug regimens, that based on preclinical and early clinical evidence might be targeting the homologous recombination defect, such as platinum compounds and PARP inhibitors. If rapid testing is performed, the patient can make a well-balanced decision. Although rapid genetic counseling and testing might cause some distress, most women reported this approach to be worthwhile. In this review the literature regarding these topics is evaluated. Answers and suggestions, useful in clinical practice are discussed.

RAPID HOME-BASED HIV TESTING TO REDUCE COSTS IN A LARGE TUBERCULOSIS COHORT STUDY

To reduce costs in a large tuberculosis household contact cohort study in Lima, Peru, we replaced laboratory-based HIV testing with home-based rapid testing. We developed a protocol and training course to prepare staff for the new strategy; these included role playing for home-based deployment of the Determine® HIV 1/2 Ag/Ac Combo HIV test. Though the rapid HIV test produced more false-positives, the overall cost per participant tested, refusal rate and time to confirmatory HIV testing were lower with the home-based rapid testing strategy compared to the original approach. Rapid testing could be used in similar research or routine care settings.