Comparable performance of antigen-detecting rapid test by healthcare worker-collected and self-collected swabs for SARS-CoV-2 diagnostic: A systematic review and meta-analysis.

Usage of self-screening tests has become increasingly relevant in public health perspective for early detection of SARS-CoV-2 infection in the transitioning era of the COVID-19 pandemic into an endemic. This study was designed to compare the diagnostic accuracy of self-conducted and health professional-conducted SARS-CoV-2 rapid antigen tests (Ag-RDTs) and whether the sample was taken from anterior nasal or nasal mid-turbinate. Eligible comparative Ag-RDTs accuracy studies were retrieved from electronic databases systematically, in accordance with PRISMA. Selected studies were assessed for risk of bias using QUADAS-2 and QUADAS-C. In total, we selected five out of 1952 studies retrieved using the keywords. The overall sensitivity for the self-collected nasal swab method and healthcare worker-collected nasopharyngeal swab method was 79% (95% CI 68-87; I2  = 62%) and 83% (95% CI 75-89; I2  = 32%), respectively, which was not statistically different (p = 0.499). Nasal mid-turbinate swabs have a significantly higher sensitivity compared to anterior nasal swabs (p < 0.01). Both sampling methods represent high and comparable specificity values of 98% (95% CI 97-99; I2  = 0%) and 99% (95% CI 98-99; I2  = 0%). Positive predictive value (range 90%-99%) and negative predictive value (range 87%-98%) were equivalent for both methods. Our findings indicated the accuracy of self-collected Ag-RDT on nasal swabs was comparable to those performed by healthcare worker-collected on nasopharyngeal swabs. Self-collected Ag-RDT could be considered as a transmission prevention method in the transition of COVID-19 pandemic.

Bimetallic Nanozyme: A Credible Tag for In Situ-Catalyzed Reporter Deposition in the Lateral Flow Immunoassay for Ultrasensitive Cancer Diagnosis.

The lateral flow immunoassay (LFIA) is a sought-after point-of-care testing platform, yet the insufficient sensitivity of the LFIA limits its application in the detection of tumor biomarkers. Here, a colorimetric signal amplification method, bimetallic nanozyme-mediated in situ-catalyzed reporter deposition (BN-ISCRD), was designed for ultrasensitive cancer diagnosis. The bimetallic nanozyme used, palladium@iridium core-shell nanoparticles (Pd@Ir NPs), had ultrahigh enzyme-like activity, which was further explained by the electron transfer of Pd@Ir NPs and the change in the Gibbs free energy during catalysis through density functional theory calculations. With gastric cancer biomarkers pepsinogen I and pepsinogen II as model targets, this assay could achieve a cutoff value of 10 pg/mL, which was 200-fold lower than that without signal enhancement. The assay was applied to correctly identify 8 positive and 28 negative clinical samples. Overall, this BN-ISCRD-based LFIA showed great merits and potential in the application of ultrasensitive disease diagnosis.

Point of care testing for hepatitis C in the priority settings of mental health, prisons and drug & alcohol facilities - the PROMPt Study.

BACKGROUND: A barrier to hepatitis C virus (HCV) cure is conventional testing. The aim of this study was to evaluate the effect of HCV antibody and RNA point-of-care-testing (POCT) on testing rates, linkage to care, treatment and acceptability of testing in three priority settings in Australia. METHODS: Participants were enrolled in an interventional cohort study at a reception prison, inpatient mental health service (MHS), and inpatient alcohol and other drug (AOD) unit-between October 2020 and December 2021. HCV POCT was performed using SD Bioline HCV antibody fingerstick test and a reflexive Xpert® HCV Viral Load Fingerstick test using capillary blood samples. A retrospective audit of HCV testing and treatment data was performed at each site for the preceding 12-month period to generate a historical control. RESULTS: 1,549 participants received a HCV antibody test with 17% (264/1,549) receiving a positive result, of which 21% (55/264) tested HCV RNA positive. Across all settings the rate of testing per year significantly increased between the historical controls and the study intervention period by three-fold (RR:2.57 95% CI: 2.32, 2.85) for HCV antibody testing and four-fold (RR:1.62; 95% CI:1.31, 2.01) for RNA testing. Treatment uptake was higher during the POCT intervention (86%, 47/55; P=0.010) compared to the historical controls (61%, 27/44). CONCLUSIONS: This study demonstrated across three settings that the use of HCV antibody and RNA POCT increased testing rates, treatment uptake linkage to care. The testing model was highly acceptable for most participants. CLINICAL TRIAL REGISTRATION: ACTRN-12621001578897.

Upconversion Nanoparticles Based Sensing: From Design to Point-of-Care Testing.

Rare earth-doped upconversion nanoparticles (UCNPs) have achieved a wide range of applications in the sensing field due to their unique anti-Stokes luminescence property, minimized background interference, excellent biocompatibility, and stable physicochemical properties. However, UCNPs-based sensing platforms still face several challenges, including inherent limitations from UCNPs such as low quantum yields and narrow absorption cross-sections, as well as constraints related to energy transfer efficiencies in sensing systems. Therefore, the construction of high-performance UCNPs-based sensing platforms is an important cornerstone for conducting relevant research. This work begins by providing a brief overview of the upconversion luminescence mechanism in UCNPs. Subsequently, it offers a comprehensive summary of the sensors' types, design principles, and optimized design strategies for UCNPs sensing platforms. More cost-effective and promising point-of-care testing applications implemented based on UCNPs sensing systems are also summarized. Finally, this work addresses the future challenges and prospects for UCNPs-based sensing platforms.

Kiwi-Inspired Rational Nanoarchitecture with Intensified and Discrete Magneto-Fluorescent Functionalities for Ultrasensitive Point-of-Care Immunoassay.

Fluorescent lateral flow immunoassays (FLFIA) is a well-established rapid detection technique for quantitative analysis. However, achieving accurate analysis of biomarkers at the pg mL-1 level using FLFIA still poses challenges. Herein, an ultrasensitive FLFIA platform is reported utilizing a kiwi-type magneto-fluorescent silica nanohybrid (designated as MFS) that serves as both a target-enrichment substrate and an optical signal enhancement label. The spatially-layered architecture comprises a Fe3O4 core, an endocarp-fibers like dendritic mesoporous silica, seed-like quantum dots, and a kiwi-flesh like silica matrix. The MFS demonstrates heightened fluorescence brightness, swift magnetic response, excellent size uniformity, and dispersibility in water. Through liquid-phase capturing and fluorescence-enhanced signal amplification, as well as magnetic-enrichment sample amplification and magnetic-separation noise reduction, the MFS-based FLFIA is successfully applied to the detection of cardiac troponin I that achieved a limit of detection at 8.4 pg mL-1, tens of times lower than those of previously published fluorescent and colorimetric lateral flow immunoassays. This work offers insights into the strategic design of magneto-fluorescent synergetic signal amplification on LFIA platform and underscores their prospects in high-sensitive rapid and on-site diagnosis of biomarkers.

Lab-in-a-Vial Rapid Test for Internet of Things-Embedded Point-of-Healthcare Protein Biomarker Detection in Bodily Fluids.

Amateurs often struggle with detecting and quantifying protein biomarkers in body fluids due to the high expertise required. This study introduces a Lab-in-a-Vial (LV) rapid diagnostic platform, featuring hydrangea-like platinum nanozymes (PtNH), for rapid, accurate detection and quantification of protein biomarkers on-site within 15 min. This method significantly enhances detection sensitivity for various biomarkers in body fluids, surpassing traditional methods such as enzyme-linked immunosorbent assays (ELISA) and lateral flow assays (LFA) by ≈250 to 1300 times. The LV platform uses a glass vial coated with specific bioreceptors such as antigens or antibodies, enabling rapid in vitro evaluation of disease risk from small fluid samples, similar to a personal ELISA-like point-of-care test (POCT). It overcomes challenges in on-site biomarker detection, allowing both detection and quantification through a portable wireless spectrometer for healthcare internet of things (H-IoT). The platform's effectiveness and adaptability are confirmed using IgG/IgM antibodies from SARS-CoV-2 infected patients and nuclear matrix protein (NMP22) from urothelial carcinoma (UC) patients as biomarkers. These tests demonstrated its accuracy and flexibility. This approach offers vast potential for diverse disease applications, provided that the relevant protein biomarkers in bodily fluids are identified.

At-home testing for respiratory viruses: a minireview of the current landscape.

The landscape of at-home testing using over-the-counter (OTC) tests has been evolving over the last decade. The United States Food and Drug Administration Emergency Use Authorization rule has been in effect since the early 2000s, and it was widely employed during the severe acute respiratory syndrome coronavirus 2 pandemic to authorize antigen and nucleic acid detection tests for use in central laboratories as well as OTC. During the pandemic, the first at-home tests for respiratory viruses became available for consumer use, which opened the door for additional respiratory virus OTC tests. Concerns may exist regarding the public's ability to properly collect samples, perform testing, interpret results, and report results to public health authorities. However, favorable comparison studies between OTC testing and centralized laboratory test results suggest that OTC testing may have a place in healthcare, and it is likely here to stay. This mini-review of OTC tests for viral respiratory diseases will briefly cover the regulatory and reimbursement environment, current OTC test availability, as well as the advantages and limitations of OTC tests.

A Lateral Flow Assay Based on Streptavidin-biotin Amplification System with Recombinase Polymerase Amplification for Rapid and Quantitative Detection of Salmonella enteritidis.

Salmonella constitutes a prevalent alimentary pathogen, instigating zoonotic afflictions. Consequently, the prompt discernment of Salmonella in sustenance is of cardinal significance. Lateral flow assays utilizing colorimetric methodologies adequately fulfill the prerequisites of point-of-care diagnostics, however, their detection threshold remains elevated, generally permitting only qualitative discernment, an impediment to the preliminary screening of nascent pathogens. In response to this conundrum, we propose a lateral flow diagnostic predicated upon a streptavidin-biotin amplification system with recombinase polymerase amplification engineered for the expeditious and quantitative discernment of Salmonella enteritidis. Trace nucleic acids within a sample undergo exponential amplification via recombinase polymerase amplification to a level discernable, constituting the initial signal amplification. Subsequently, along the test line (T-line) of the lateral flow strip, the chromatic signal undergoes augmentation by securing a greater quantity of AuNPs through the magnification capacity of the streptavidin-biotin mechanism, affecting the second signal amplification. Quantitative results are procured via smartphone capture and transferred to computer software for precise calculation of the targeted quantity. The lateral flow strip exhibits a LOD at 19.41 CFU/mL for cultured S. enteritidis. The RSD of three varying concentrations were respectively 3.74 %, 5.96 %, and 4.25 %.

Satisfaction with home blood sampling methods and expectations for future point-of-care testing in phenylketonuria: Perspectives from patients and professionals.

INTRODUCTION: Phenylketonuria (PKU) requires regular phenylalanine monitoring to ensure optimal outcome. However, home sampling methods used for monitoring suffer high pre-analytical variability, inter-laboratory variability and turn-around-times, highlighting the need for alternative methods of home sampling or monitoring. METHODS: A survey was distributed through email and social media to (parents of) PKU patients and professionals working in inherited metabolic diseases in Denmark, The Netherlands, and United Kingdom regarding satisfaction with current home sampling methods and expectations for future point-of-care testing (POCT). RESULTS: 210 parents, 156 patients and 95 professionals completed the survey. Countries, and parents and patients were analysed together, in absence of significant group differences for most questions. Important results are: 1) Many patients take less home samples than advised. 2) The majority of (parents of) PKU patients are (somewhat) dissatisfied with their home sampling method, especially with turn-around-times (3-5 days). 3) 37% of professionals are dissatisfied with their home sampling method and 45% with the turn-around-times. 4) All responders are positive towards developments for POCT: 97% (n = 332) of (parents of) patients is willing to use a POC-device and 76% (n = 61) of professionals would recommend their patients to use a POC-device. 5) Concerns from all participants for future POC-devices are costs/reimbursements and accuracy, and to professionals specifically, accessibility to results, over-testing, patient anxiety, and patients adjusting their diet without consultation. CONCLUSION: The PKU community is (somewhat) dissatisfied with current home sampling methods, highlighting the need for alternatives of Phe monitoring. POCT might be such an alternative and the community is eager for its arrival.

Implementation and Performance of a Point-of-Care COVID-19 Test Program in 4000 California Schools.

OBJECTIVE: To evaluate the feasibility and accuracy of an unprecedented COVID-19 antigen testing program in schools, which required a healthcare provider order, laboratory director, a Clinical Laboratory Improvement Amendments certificate of waiver, as well as training of school personnel. STUDY DESIGN: Descriptive report of a point-of-care, school-based antigen testing program in California from August 1st, 2021 through May 30, 2022, in which participants grades K-12 self-swabbed and school personnel performed testing. Participants included 944 009 students, personnel, and community members from 4022 California kindergarten through high schools. Outcomes measured include sensitivity and specificity (with polymerase chain reaction [PCR] as comparator) of the Abbott BinaxNOW antigen test, number of tests performed, and active infections identified. RESULTS: Of 102 022 paired PCR/antigen tests, the overall sensitivity and specificity for the antigen test was 81.2% (95% CI: 80.5%-81.8%) and 99.6% (95% CI: 99.5%-99.6%), respectively, using cycle threshold values <30. During January through March 2022, the highest prevalence period, the positive predictive value of antigen testing was 94.7% and the negative predictive value was 94.2%. Overall, 4022 school sites were enrolled and 3 987 840 million antigen tests were performed on 944 009 individuals. A total of 162 927 positive antigen tests were reported in 135 163 individuals (14.3% of persons tested). CONCLUSIONS: Rapidly implementing a school-based testing program in thousands of schools is feasible. Self-swabbing and testing by school personnel can yield accurate results. On-site COVID-19 testing is no longer necessary in schools, but this model provides a framework for future infectious disease threats.

Biosensor-based multiple cross displacement amplification platform for visual and rapid identification of hepatitis C virus.

Hepatitis C remains a global health problem, especially in poverty-stricken areas. A rapid and sensitive point-of-care (POC) diagnostic tool is critical for the early detection and timely treatment of hepatitis C virus (HCV) infection. Here, for the first time, we reported a novel molecular diagnostic assay, termed reverse transcription multiple cross displacement amplification integrated with a gold-nanoparticle-based lateral flow biosensor (RT-MCDA-AuNPs-LFB), which was developed for rapid, sensitive, specific, and visual identification of HCV. HCV-RT-MCDA induced rapid isothermal amplification through a specific primer set targeting the 5'untranslated region gene from the major HCV genotypes 1b, 2a, 3b, 6a, and 3a that are prevalent in China. The optimal reaction temperature and time for RT-MCDA-AuNPs-LFB were 68°C and 25 min, respectively. The limit of detection of the assay was 10 copies per test, and the specificity was 100% for the experimental strains. The whole detection procedure, including crude nucleic acid isolation (~5 min), RT-MCDA (68°C, 25 min), and visual AuNPs-LFB result confirmation (less than 2 min), was performed within 35 min. The preliminary results indicated that the HCV-RT-MCDA-AuNPs-LFB assay could be a valuable tool for sensitive, specific, visual, cost-saving, and rapid detection of HCV and has potential as a POC diagnostic platform for field screening and early clinical detection of HCV infection.

Simple, sensitive, and visual detection of 12 respiratory pathogens with one-pot-RPA-CRISPR/Cas12a assay.

Respiratory infections pose a serious threat to global public health, underscoring the urgent need for rapid, accurate, and large-scale diagnostic tools. In recent years, the CRISPR/Cas (clustered regularly interspaced short palindromic repeats/CRISPR-associated) system, combined with isothermal amplification methods, has seen widespread application in nucleic acid testing (NAT). However, achieving a single-tube reaction system containing all necessary components is challenging due to the competitive effects between recombinase polymerase amplification (RPA) and CRISPR/Cas reagents. Furthermore, to enable precision medicine, distinguishing between bacterial and viral infections is essential. Here, we have developed a novel NAT method, termed one-pot-RPA-CRISPR/Cas12a, which combines RPA with CRISPR molecular diagnostic technology, enabling simultaneous detection of 12 common respiratory pathogens, including six bacteria and six viruses. RPA and CRISPR/Cas12a reactions are separated by paraffin, providing an independent platform for RPA reactions to generate sufficient target products before being mixed with the CRISPR/Cas12a system. Results can be visually observed under LED blue light. The sensitivity of the one-pot-RPA-CRISPR/Cas12a method is 2.5 × 100 copies/µL plasmids, with no cross-reaction with other bacteria or viruses. Additionally, the clinical utility was evaluated by testing clinical isolates of bacteria and virus throat swab samples, demonstrating favorable performance. Thus, our one-pot-RPA-CRISPR/Cas12a method shows immense potential for accurate and large-scale detection of 12 common respiratory pathogens in point-of-care testing.

Diagnostic accuracy of the maximal systolic acceleration to detect peripheral arterial disease.

BACKGROUND: Diagnosing peripheral arterial disease (PAD) can be challenging owing to medial arterial calcification (MAC) in patients with diabetes mellitus (DM) and chronic kidney disease (CKD). Current bedside tests, such as the ankle-brachial index and toe-brachial index, are often insufficient. The maximal systolic acceleration (ACCmax) is a velocimetric Doppler-derived parameter and could be a new promising test in the diagnostic workup of these patients. The primary aim of this study was to evaluate the diagnostic performance of the ACCmax to detect PAD. METHODS: A retrospective cohort study was performed in a tertiary referral hospital. Patients ≥18 years old with suspected PAD who underwent ACCmax measurement(s) along with computed tomography angiography of the abdominal aorta and lower extremities (reference test) were eligible for inclusion. ACCmax measurements of the posterior tibial artery, anterior tibial artery and peroneal artery were collected. Diagnostic performance was assessed by using sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and area under the curve (AUC). RESULTS: In total, 340 patients (618 limbs) were included. Approximately 40% suffered from DM and 30% had CKD. Diagnostic performance of the ACCmax to detect PAD for the posterior tibial artery showed a sensitivity of 90%, specificity of 93%, positive likelihood ratio of 12.83, and negative likelihood ratio of 0.11 (AUC, 0.953). For the anterior tibial artery, these results were 94%, 97%, 32.06, and 0.06 (same sequence as presented before) with an AUC of 0.984. The peroneal artery had a performance of 86%, 89%, 7.51, and 0.16, respectively (AUC, 0.893). Diagnostic accuracy of the ACCmax did not diminish in subgroup analysis for patients with DM or CKD. CONCLUSIONS: The ACCmax showed excellent diagnostic performance to detect PAD, independent of patients prone to medial arterial calcification.

Development of two novel on-site detection visualization methods for murine hepatitis virus based on the multienzyme isothermal rapid amplification.

Murine hepatitis virus (MHV) infection is one of the most prevalent types of mice infection in laboratory. MHV could cause death in mice and even interfere with the results in animal experiments. Herein, we developed two isothermal approaches based on the Multienzyme Isothermal Rapid Amplification (MIRA), for rapid detection of MHV in conserved M gene. We designed and screened several pairs of primers and probes and the isothermal fluorescence detector was applied for the exonuclease Ⅲ reverse transcription MIRA (exo-RT-MIRA) assay. To further simplify the workflow, the portable fluorescence visualization instrument, also as a palm-sized handheld system, was used for the naked-eye exo-RT-MIRA assay. The amplification temperature and time were optimized. The assay could be processed well at 42 °C 20 min for the exo-RT-MIRA and the naked-eye exo-RT-MIRA assay. The limit of detection (LoD) of the exo-RT-MIRA assay was 43.4 copies/µL. The LoD of the naked-eye exo-RT-MIRA assay was 68.2 copies/µL. No nonspecific amplifications were observed in the two assays. A total of 107 specimens were examined by qPCR and two assays developed. The experimental results statistical analysis demonstrated that the exo-RT-MIRA assay with the qPCR yielded sufficient agreement with a kappa value of 1.000 (p < 0.0001). The results also exhibited a good agreement (kappa value, 0.961) (p < 0.0001) between the naked-eye exo-RT-MIRA assay and the qPCR assay. In our study, the exo-RT-MIRA assay and the naked-eye exo-RT-MIRA assay presented the possibility of new methods in MHV point-of-testing diagnosis.

Performance evaluation of a self-administered point-of-care test for anal HPV screening in PrEP users: data from a community-based PrEP service.

OBJECTIVES: In this study, we compared the performance of a self-administered point-of-care test (POCT) for anal human papillomavirus (HPV) screening with laboratory gold-standard test in pre-exposure prophylaxis (PrEP) users and evaluated its feasibility. METHODS: We enrolled PrEP users from a local community-based PrEP service. Each participant self-collected an anal swab to test anal HPV with a PCR POCT capable of detecting 14 high-risk HPV genotypes. Anonymous questionnaires on self-sampling feasibility were completed. Participants were then referred to local clinics to undergo standard viral genotyping. Concordance between POCT and gold-standard test was measured with absolute agreement and Cohen's kappa. Receiver operating characteristic (ROC) curves were used to calculate POCT sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). RESULTS: 179 subjects got a valid POCT result, most of them men (98.3%) and men who have sex with men (90.4%). 68.2% tested positive for at least one high-risk HPV genotype on POCT. 150 feasibility questionnaires were collected: 92.7% of compilers found the self-swab easy to perform. For 178 subjects, a gold-standard test valid result was also available: 77% tested positive for at least one high-risk HPV genotype. The median time elapsed between the two tests was 9.8 months, due to COVID-19-related service interruptions. Agreement between POCT and gold-standard test was 79.3% (Cohen's kappa=0.49). POCT showed a sensitivity of 81.0%, a specificity of 73.8%, a PPV of 91.0% and an NPV of 54.4%. CONCLUSIONS: POCT showed a moderate agreement with gold-standard test and a discrete sensitivity and specificity, suggesting that it could be a useful and feasible additional tool for HPV screening, especially in low-resource and community-based settings.

Point-of-care testing for sexually transmitted infections and HIV pre-exposure prophylaxis among pregnant women in South Africa, 2021-2022: randomised controlled trial.

OBJECTIVE: Pregnant and postpartum women (PPW) in Southern Africa are at increased risk of acquiring HIV and curable sexually transmitted infections (STIs). Oral pre-exposure prophylaxis (PrEP) is safe and effective to use during pregnancy to reduce HIV acquisition and vertical transmission. Point-of-care (POC) STI testing can identify PPW at risk of HIV and facilitate risk-differentiated and person-centred counselling to improve PrEP initiation, persistence and adherence. We evaluated the impact of POC STI testing compared with STI syndromic management on PrEP outcomes among PPW in Cape Town, South Africa. METHODS: The STI and PrEP in Pregnancy Study enrolled PPW without HIV and ≤34 weeks pregnant at their regular antenatal care visit with follow-up after 1 month. PPW were randomised to receive POC STI testing or STI syndromic management. PPW randomised to POC STI testing self-collected vaginal swabs for Chlamydia trachomatis, Neisseria gonorhoeae and Trichomonas vaginalis (Cepheid GeneXpert) testing and were offered same-day treatment if diagnosed. We compared PrEP initiation at baseline, PrEP prescription refill at 1 month (persistence) and adherence through tenofovir-diphosphate detection in dried blood spots by randomisation arm. In a secondary analysis, we evaluated the association between an STI diagnosis (positive STI test or reporting STI symptoms) with PrEP outcomes. RESULTS: We enrolled and randomised 268 pregnant women. Twenty-eight per cent of women were diagnosed with ≥1 STI. Overall, 65% of women initiated and 79% persisted on PrEP with no significant differences by randomisation arm. Secondary analysis demonstrated that an STI diagnosis (positive STI test or reporting STI symptoms) was associated with higher PrEP initiation (adjusted relative risk=1.28; 95% CI 1.08 to 1.52), controlling for arm, maternal and gestational age. CONCLUSIONS: POC STI testing was not associated with PrEP initiation or persistence relative to syndromic management. However, improving STI diagnosis by supplementing syndromic management with POC STI testing could improve PrEP initiation among PPW. TRIAL REGISTRATION NUMBER: NCT03902418; Clinical Trials.gov; 1 April 2019.

Unnecessary antibiotic use in men who have sex with men (MSM) with anogenital symptoms attending a sexual health clinic: a retrospective analysis.

OBJECTIVES: To quantify the amount of unnecessary antibiotics, in particular ceftriaxone, given to men who have sex with men (MSM) with anogenital symptoms as part of presumptive management in an urban sexual health clinic and examine factors associated with unnecessary ceftriaxone. METHODS: This is a retrospective cross-sectional analysis of electronic records from all visits involving MSM reporting symptoms of bacterial sexually transmitted infection (STI) and who received presumptive antibiotics at Sydney Sexual Health Centre. The following variables were extracted: demographic and sexual behaviour data, presenting symptoms, prior STI diagnoses, use of anoscopy, use of point-of-care microscopy, prescriptions of antibiotics and subsequent nucleic acid amplification testing (NAAT) results for chlamydia and gonorrhoea in all anatomical sites (urethra, pharynx and rectum). We defined unnecessary antibiotic as an agent prescribed to treat an STI organism that was subsequently not detected. RESULTS: Among 1061 visits in this analysis, 41.8% yielded negative NAAT results for both chlamydia and gonorrhoea in all anatomical sites. There were 44.3% of visits which had positive gonorrhoea NAAT result in at least one anatomical site. There were 187 courses of ceftriaxone prescribed in patients who tested negative for gonorrhoea in all anatomical sites and therefore were unnecessary. Unnecessary ceftriaxone prescribing occurred in 50.2% of visits with anorectal symptoms, 19.6% of scrotal symptoms and 7.3% of urethral symptoms. Microscopy was associated with significantly less unnecessary ceftriaxone in urethral but not anorectal or scrotal presentations. In multivariable analysis, the following factors were associated with a higher likelihood of unnecessary ceftriaxone use: anorectal symptoms, scrotal symptoms, gonorrhoea in the preceding year, contact of a bacterial STI and living with HIV. CONCLUSIONS: This study highlights the significant amount of unnecessary ceftriaxone used for STI symptoms in MSM. A new pathway incorporating rapid point-of-care molecular testing in symptomatic patients may improve the precision of antibiotic prescribing and reduce unnecessary use.

Acceptability of digital vending machines to access STI and HIV tests in two UK cities.

OBJECTIVES: Prompt HIV and STI diagnosis and treatment is a public health priority and relies on accessible testing. Technology-based approaches to distribute test kits have the potential to increase access to testing. We evaluated the acceptability and uptake of vending machines in publicly available settings in Brighton and Hove (BH) and Bristol, North Somerset and South Gloucestershire (BNSSG), to distribute HIV rapid self-test and STI self-sample kits. METHODS: Seven machines were installed in BH and four in BNSSG. User characteristics, proportion of kits returned and test results, taken from the machine database and clinic records, combined with online questionnaires completed by self-recruited users and analysed using Stata and SPSS. RESULTS: 2536 kits were dispensed over 12 months (April 2022 to March 2023). The STI self-sample kits were most popular (74% of vends). 78% of kits dispensed were among users aged 16-35 years and 56% identified as male. 68% and 59% of users had either not tested in the last 12 months or never tested for HIV and STIs, respectively. 51% of STI kits were returned via post, lower than the local online service (65%). 208 users completed questionnaires. Convenience, desire for instant access and increased confidentiality were the most common reasons for using machines. 92% of respondents thought the machines were user-friendly and 97% would recommend the service. Concerns about safety and privacy while using the machine were reported by 42% and 66% of respondents. CONCLUSIONS: This study demonstrates that vending machines are an acceptable and effective means of accessing infrequent or never testers in the general population and can act as a horizontal intervention to tackle HIV and STIs. Research is needed to understand optimal machine locations to assure privacy and safety along with the long-term impact on sexual health services.

Amplification-free nucleic acids detection with next-generation CRISPR/dx systems.

CRISPR-based diagnostics (CRISPR/Dx) have revolutionized the field of molecular diagnostics. It enables home self-test, field-deployable, and point-of-care testing (POCT). Despite the great potential of CRISPR/Dx in diagnoses of biologically complex diseases, preamplification of the template often is required for the sensitive detection of low-abundance nucleic acids. Various amplification-free CRISPR/Dx systems were recently developed to enhance signal detection at sufficient sensitivity. Broadly, these amplification-free CRISPR/Dx systems are classified into five groups depending on the signal enhancement strategies employed: CRISPR/Cas12a and/or CRISPR/Cas13a are integrated with: (1) other catalytic enzymes (Cas14a, Csm6, Argonaute, duplex-specific nuclease, nanozyme, or T7 exonuclease), (2) rational-designed oligonucleotides (multivalent aptamer, tetrahedral DNA framework, RNA G-quadruplexes, DNA roller machine, switchable-caged guide RNA, hybrid locked RNA/DNA probe, hybridized cascade probe, or "U" rich stem-loop RNA), (3) nanomaterials (nanophotonic structure, gold nanoparticle, micromotor, or microbeads), (4) electrochemical and piezoelectric plate biosensors (SERS nanoprobes, graphene field-effect transistor, redox probe, or primer exchange reaction), or (5) cutting-edge detection technology platforms (digital bioanalysis, droplet microfluidic, smartphone camera, or single nanoparticle counting). Herein, we critically discuss the advances, pitfalls and future perspectives for these amplification-free CRISPR/Dx systems in nucleic acids detection. The continued refinement of these CRISPR/Dx systems will pave the road for rapid, cost-effective, ultrasensitive, and ultraspecific on-site detection without resorting to target amplification, with the ultimate goal of establishing CRISPR/Dx as the paragon of diagnostics.

A method for Porphyromonas gingivalis based on recombinase polymerase amplification and lateral flow strip technology.

OBJECTIVE: A practical visual detection method was established to detect Porphyromonas gingivalis (P. gingivalis) by employing a combination of recombinase polymerase amplification and lateral flow strips (RPA-LF) assay, designed for conducting point-of-care testing in clinical settings. METHODS: Primers and probes targeting the P. gingivalis pepO gene were designed. The RPA-LF assay was established by optimising reaction temperature and time, determining the limit of detection (LOD). The specificity of the method was determined by assessing its cross-reactivity with deoxyribonucleic acid from 23 pathogenic bacteria. Finally, the clinical samples from healthy controls (n = 30) and individuals with periodontitis (n = 31) were analysed. The results were compared with those obtained using real-time polymerase chain reaction (PCR). RESULTS: The optimal reaction temperature and time were 39 °C and 12 min. The method exhibited a LOD at 6.40 × 10-4 µg/mL and demonstrated high specificity and sensitivity during cross-reactivity assessment. The RPA-LF assay achieved a P. gingivalis detection rate of 84 % in individuals with periodontitis and 3 % in healthy controls. The results were consistent with those obtained through real-time PCR. CONCLUSION: An RPA-LF assay was developed for detecting P. gingivalis, characterised by its high sensitivity, high specificity, simple operational procedure, and rapid reaction time.