Development and evaluation of a lyophilization protocol for colorimetric RT-LAMP diagnostic assay for COVID-19.

Molecular diagnostics involving nucleic acids (DNA and RNA) are regarded as extremely functional tools. During the 2020 global health crisis, efforts intensified to optimize the production and delivery of molecular diagnostic kits for detecting SARS-CoV-2. During this period, RT-LAMP emerged as a significant focus. However, the thermolability of the reagents used in this technique necessitates special low-temperature infrastructure for transport, storage, and conservation. These requirements limit distribution capacity and necessitate cost-increasing adaptations. Consequently, this report details the development of a lyophilization protocol for reagents in a colorimetric RT-LAMP diagnostic kit to detect SARS-CoV-2, facilitating room-temperature transport and storage. We conducted tests to identify the ideal excipients that maintain the molecular integrity of the reagents and ensure their stability during room-temperature storage and transport. The optimal condition identified involved adding 5% PEG 8000 and 75 mM trehalose to the RT-LAMP reaction, which enabled stability at room temperature for up to 28 days and yielded an analytical and diagnostic sensitivity and specificity of 83.33% and 90%, respectively, for detecting SARS-CoV-2. This study presents the results of a lyophilized colorimetric RT-LAMP COVID-19 detection assay with diagnostic sensitivity and specificity comparable to RT-qPCR, particularly in samples with high viral load.

Comparative evaluation of the diagnostic accuracies of four different malaria rapid diagnostic test kits available in Ghana.

Malaria rapid diagnostic test (mRDT) kit is one of the techniques for diagnosing malaria. Due to its inherent advantages over the microscopy technique, several brands of the kit have flooded malaria endemic countries, without prior in-country evaluation. Two of such mRDT kits are Oscar (India) and Standard Q (Korea Republic). In this study, the performance of Oscar and Standard Q mRDT kits were compared to First Response (India) and CareStart (USA) mRDTs, which have been evaluated and deployed for use approved by the Ministry of Health (MOH). In this comparative study, whole blood samples were collected from patients suspected of malaria. Plasmodium falciparum was detected in each sample using nested polymerase chain reaction (nPCR), microscopy and the four mRDTs. The sensitivities, specificities, accuracies, positive and negative predictive values and accuracies of the mRDTs were determined using nPCR as a reference technique. Kappa statistic was used to determine the level of agreement among the techniques. Two hundred (200) blood samples were analyzed in this study. The overall detection rates of P. falciparum by microscopy, First Response, CareStart, Oscar-PfHRP2, Standard Q mRDT kits and nPCR were 31.5%, 34.5%, 33.5%, 32%, 31% and 43% (x2 = 6.1, p = 0.046), respectively. The accuracies of CareStart and First Response were comparable (90.5% vs. 89.5%). Further, comparing their sensitivities, Oscar-PfHRP2 was 74.4% (95% confidence interval (CI): 63.9-83.2) while that of Standard Q was 72.1% (95% CI: 61.4-81.2), with comparable accuracies (Oscar-PfHRP2-89% and Standard Q -88%). Apart from First Response that was 98.3% specific, the others were 100% specific. Kappa test revealed perfect diagnostic agreement (κ = 0.90-0.98) among the four mRDTs. That notwithstanding, Oscar-PfHRP2 agreed better with CareStart (κ = 0.94) and First Response (κ = 0.92) compared to the agreement between Standard Q and, CareStart (κ = 0.92) and First Response (κ = 0.90). Taken together, the diagnostic performance of the four mRDT kits were statistically similar. That notwithstanding, new mRDT kits should be evaluated prior to deployment for use.

Performance Evaluation of Newly-Developed Tumor Markers Assay Kit Based on Flow Fluorescence Assay.

BACKGROUND: The purpose of this study is to evaluate the performance of recently developed tumor marker clinical kits in China, with the aim of encouraging local medical technology innovation and thus narrowing the research and development gap with foreign kits. METHODS: The newly established reagent kits were analyzed on the TESMI F3999-Luminex200 flow lattice instrument to verify precision, sensitivity (blank limit), linearity, anti-interference ability, carry-over contamination rate, hook effect, and reference interval verification. Additionally, the newly established reagent kits were compared to other commercially available detection kits (reference reagent kits) to analyze the correlation between the two types of kits. RESULTS: The intra-assay and inter-assay precision had coefficients of variations (CVs) less than 3.50% and 6.91%, respectively. The tumor marker blank limits were lower than the manufacturer's statement. The newly established reagent kits demonstrated excellent linearity (r > 0.99). Rheumatoid factor, triglycerides, bilirubin, and hemoglobin did not have significant interference with the determination of tumor markers. The carry-over contamination rates were all much lower than 3%. At extremely high concentrations of AFP (277,335 ng/mL and 1,031,424 ng/mL), the measured tumor marker values were higher than the upper limit of the linear range and no hook effect occurred. The reference interval was suitable for use in clinical laboratory settings. Correlation analysis indicated a satisfactory relevance and consistency between the newly developed reagent kits and reference reagent kits, with correlation coefficients of r > 0.967 among 654 patients and healthy individuals. CONCLUSIONS: The newly developed reagent kits for tumor markers performed well in all evaluated parameters, having the potential for clinical promotion and application.

Overview of Modern Commercial Kits for Laboratory Diagnosis of African Swine Fever and Swine Influenza A Viruses.

Rapid and early detection of infectious diseases in pigs is important, especially for the implementation of control measures in suspected cases of African swine fever (ASF), as an effective and safe vaccine is not yet available in most of the affected countries. Additionally, analysis for swine influenza is of significance due to its high morbidity rate (up to 100%) despite a lower mortality rate compared to ASF. The wide distribution of swine influenza A virus (SwIAV) across various countries, the emergence of constantly new recombinant strains, and the danger of human infection underscore the need for rapid and accurate diagnosis. Several diagnostic approaches and commercial methods should be applied depending on the scenario, type of sample and the objective of the studies being implemented. At the early diagnosis of an outbreak, virus genome detection using a variety of PCR assays proves to be the most sensitive and specific technique. As the disease evolves, serology gains diagnostic value, as specific antibodies appear later in the course of the disease (after 7-10 days post-infection (DPI) for ASF and between 10-21 DPI for SwIAV). The ongoing development of commercial kits with enhanced sensitivity and specificity is evident. This review aims to analyse recent advances and current commercial kits utilised for the diagnosis of ASF and SwIAV.

Comparison of Fecal MicroRNA Isolation Using Various Total RNA Isolation Kits.

Fecal specimens have long been regarded as promising sources for gastrointestinal cancer screening and have, thus, been extensively investigated in biomarker research. MicroRNAs (miRNAs) are small, non-coding RNA molecules involved in regulating various biological processes. They are commonly dysregulated during tumor development and exhibit differential expression in feces. To assess the preanalytical feasibility of fecal miRNA analysis, we systematically compared the performance of commonly used total RNA extraction methods. Fecal samples from healthy subjects were utilized for this evaluation. Various methods, including miRNeasy, Universal, Trizol, RNeasy, and mirVana kits, were employed to isolate total RNA. MiRNA expression analyses were conducted using TaqMan or SYBR Green qRT-PCR for a subset of miRNAs, with externally spiked-in cel-miR-39 used for normalization. Most methods demonstrated similar performance in terms of the total RNA concentration and purity. Externally spiked cel-miR-39 and endogenous miRNAs (RNU6b, miR-16, and miR-21) exhibited comparable concentrations across the different RNA isolation methods, whereas the RNeasy mini kit consistently yielded lower values. Our findings suggest that various isolation methods produce reproducible and comparable miRNA expression results, supporting the potential comparability and translational applicability of miRNA-based biomarker research in the future.

Seegene Anyplex II assays detect HPV consistently using DNA extracts from different extraction methods.

The efficiency of PCR-based diagnostic assays can be impacted by the quality of DNA template, and anal samples can be particularly problematic due to the presence of faecal contaminants. Here, we compared the Quick-DNA Viral Kit (Zymo, Zymo Research, CA) and MagNA Pure 96 DNA and Viral NA Small Volume Kit (MP96, Roche) for use of the Seegene Anyplex II HPV28 assay (Anyplex28, Seegene) with anal samples. A total of 94 anal samples extracted using the MP96 and Zymo kits were tested via the Anyplex28, which detects high-risk human papillomavirus (HR-HPV, Panel A) and low-risk (LR-HPV, Panel B) HPV types. Testing the HR-HPV types (Panel A), 86 (91.5%) MP96 and 84 (89.4%) Zymo samples were deemed assessable. Overall agreement between the two methods was 87/94 (92.6%, 95% CI: 85.3-97.0) with the Kappa value of 0.678 (0.5-0.9). Of the 87 assessable samples, 50 (57.5%) were concordant, 34 (39.1%) partially concordant, and 10 (11.5%)discordant. In conclusion, the Anyplex28 produces comparable HPV genotyping results when using DNA extracts from either of these two methods.

Multicenter evaluation of the Toxoplasma gondii Real-TM (Sacace) kit performance for the molecular diagnosis of toxoplasmosis.

The molecular detection of Toxoplasma gondii DNA is a key tool for the diagnosis of disseminated and congenital toxoplasmosis. This multicentric study from the Molecular Biology Pole of the French National Reference Center for toxoplasmosis aimed to evaluate Toxoplasma gondii Real-TM PCR kit (Sacace). The study compared the analytical and clinical performances of this PCR assay with the reference PCRs used in proficient laboratories. PCR efficiencies varied from 90% to 112%; linearity zone extended over four log units (R2 > 0.99) and limit of detection varied from 0.01 to ≤1 Tg/mL depending on the center. Determined on 173 cryopreserved DNAs from a large range of clinical specimens, clinical sensitivity was 100% [106/106; 95 confidence interval (CI): 96.5%-100%] and specificity was 100% (67/67; 95 CI: 94.6%-100%). The study revealed two potential limitations of the Sacace PCR assay: the first was the inconsistency of the internal control (IC) when added to the PCR mixture. This point was not found under routine conditions when the IC was added during the extraction step. The second is a lack of practicality, as the mixture is distributed over several vials, requiring numerous pipetting operations. Overall, this study provides useful information for the molecular diagnosis of toxoplasmosis; the analytical and clinical performances of the Sacace PCR kit were satisfactory, the kit having sensitivity and specificity similar to those of expert center methods and being able to detect low parasite loads, at levels where multiplicative analysis gives inconsistently positive results. Finally, the study recommends multiplicative analysis in particular for amniotic fluids, aqueous humor, and other single specimens.

Harmonization of Zika serological assays and comparative evaluation of two commercial ZIKA IgG ELISA kits.

The interpretation for Zika virus serology results is challenging due to high antibody cross reactivity with other flaviviruses. This limits availability of reliable and accurate methods for serosurveillance studies to understand the disease burden. Therefore, we conducted study to harmonize anti-Zika IgG antibody detection assays with 1st WHO International Standard (16/352) and working standard (16/320) for anti-Zika virus antibody.Additionally, evaluated NuGenTMZIKA-IgG and NovaLisa®ZIKA virus IgG-Capture ELISA using a panel of 278 seraFurther, 106 samples positive for other-flavi viruses were taken for assessing cross-reactivity of the assay, all serums were further tested by Zika-PRNT. The results of this study indicates satisfactory performance of both the assays. Serological and neutralization assays were calibrated according to the international standards. This will help in understanding antibody dynamics in serosurveillance and vaccine studies. However the performance of the kits with possibilities of cross-reactivity will have to be verified by coupling ZIKV and DENV specific ELISA.

Performance evaluation of a rapid immunochromatographic test kit in detecting bovine mastitis-causing streptococci.

Mastitis causes significant economic losses to the dairy industry due to decreased milk production in infected cows. Identification of mastitis-causing pathogens, such as streptococci, is necessary for selecting an effective antibiotic for treating mastitis. Although bacterial cultivation is widely used for pathogen identification, it requires more than 24 hr to complete. Contrarily, Lateral flow assays are simple, rapid, and inexpensive testing procedures. In this study, the effectiveness of an immunochromatographic test kit for detecting streptococci in milk samples from cows with clinical mastitis was evaluated as an alternative to bacterial cultivation. The performance of the immunochromatographic test kit for detecting mastitis-causing pathogens was compared with that of bacterial cultivation and real-time quantitative polymerase chain reaction (qPCR). The sensitivity and specificity of the immunochromatographic test kit were 0.800 and 0.875, respectively, compared with bacterial cultivation. Additionally, the κ statistic values of the immunochromatographic test kit was 0.667, indicating substantial agreement with the results of bacterial cultivation. Statistically, sensitivity and specificity of the immunochromatographic kit and real-time qPCR did not differ significantly; thus, the immunochromatographic test kit detected mastitis-causing streptococci as effectively as real-time qPCR. Therefore, the immunochromatographic kit is a rapid, inexpensive, and simple method for detecting streptococci and contributes to the timely selection of appropriate antibiotics for treatment and promotes early recovery from mastitis.

Analytical assessment of clinical sensitivity and specificities of pharmaceutical rapid SARS-CoV-2 detection nasopharyngeal swab testing kits in Pakistan.

Despite of the global unity against COVID-19 pandemic, the threat of SARS-CoV-2 variants on the lives of human being is still not over. SARS-CoV-2 pandemic has urged the need of rapid viral detection at earliest. To cope with gradually expanding scenario of SARS-CoV-2, accurate diagnosis is extremely crucial factor which should be noticed by international health organizations. Limited research followed by sporadic marketing of SARS-CoV-2 rapid pharmaceutical detection kits raises critical questions against quality assurance and quality control measures. Herein we aimed to interrogate effectivity and specificity analysis of SARS-CoV-2 pharmaceutical rapid detection kits (nasopharyngeal swab based) using conventional gold standard triple target real-time polymerase chain reaction (USFDA approved). A cross-sectional study was conducted over 1500 suspected SARS-CoV-2 patients. 100 real time-PCR confirmed patients were evaluated for pharmaceutical RDT kits based upon nasopharyngeal swab based kits. The SARS-CoV-2 nasopharyngeal swab based rapid diagnostic kit (NSP RDTs) analysis showed 78% reactivity. Among real time PCR confirmed negative subjects, 49.3% represented false positivity. The positive predictive analysis revealed 67.82%, while negative predictive values were 64.40%. The NSP RDTs showed limited sensitivities and specificities as compared to gold standard real time PCR. Valid and authentic detection of SARS-CoV-2 is deemed necessary for accurate COVID-19 surveillance across the globe. Current study highlights the potential consequences of inadequate detection of SARS-CoV-2 and emerging novel mutants, compromising vaccine preventable diseases. Current study emphasizes need to wake higher authorities including strategic organizations for designing adequate measures to prevent future SARS-CoV-2 epidemics.

Spotlights on the trends in performance assessment of qualitative in vitro diagnostic medical devices in transfusion medicine.

For reliable clinical decisions in transfusion medicine, assessing the performance of qualitative tests performed in medical laboratories is critical. When false results are reported, these can lead to an adverse reaction to blood components. Good performance assessment practices are essential for this kind of scenario, and they still remain as one of the many unmet high-priority challenges in this area. This paper aims to provide an overview of the current trends in this field. A review of the IFCC-IUPC. qualitative vocabulary was carried out, and a particular focus was given to the evaluation protocols CLSI EP12-A3 and Eurachem AQA, such as the European Union Regulation for class D in vitro diagnostic medical devices. There is a consistency between the current protocols and recognized performance assessment principles, which are mandatory in transfusion service labs. We believe that a revised imprecision interval approach and models based on emerging qualitative test types may prove beneficial in the long run. It is also important to emphasize the uncertainty of proportions to mitigate the risk of misclassification.

Diagnostic performance evaluation of urine HIV-1 antibody rapid test kits in a real-life routine care setting in China.

OBJECTIVES: To evaluate the diagnostic performance of urine HIV antibody rapid test kits in screening diverse populations and to analyse subjects' willingness regarding reagent types, purchase channels, acceptable prices, and self-testing. DESIGNS: Diagnostic accuracy studies PARTICIPANTS: A total of 2606 valid and eligible samples were collected in the study, including 202 samples from female sex workers (FSWs), 304 persons with injection drug use (IDU), 1000 pregnant women (PW), 100 subjects undergoing voluntary HIV counselling and testing (VCT) and 1000 students in higher education schools or colleges (STUs). Subjects should simultaneously meet the following inclusion criteria: (1) being at least 18 years old and in full civil capacity, (2) signing an informed consent form and (3) providing truthful identifying information to ensure that the subjects and their samples are unique. RESULTS: The sensitivity, specificity and area under the curve (AUC) of the urine HIV-1 antibody rapid test kits were 92.16%, 99.92% and 0.960 (95% CI: 0.952 to 0.968, p<0.001), respectively, among 2606 samples collected during on-site screenings. The kits showed good diagnostic performance in persons with IDU (AUC, 1.000; 95% CI, 1.000 to 1.000, p<0.001), PW (AUC, 0.999; 95% CI, 0.999 to 1.000, p<0.001) and FSWs (AUC, 1.000; 95% CI, 1.000 to 1.000, p<0.001). The AUC of the urine reagent kits in subjects undergoing VCT was 0.941 (95% CI: 0.876 to 0.978, p<0.001). The 'acceptable price' had the greatest influence on STUs (Pi=1.000) and PW (Pi=1.000), the 'purchase channel' had the greatest influence on subjects undergoing VCT (Pi=1.000) and persons with IDU (Pi=1.000) and the 'reagent types' had the greatest influence on FSWs (Pi=1.000). CONCLUSIONS: The rapid urine test kits showed good diagnostic validity in practical applications, despite a few cases involving misdiagnosis and underdiagnosis.

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.

Malaria elimination in Ghana: recommendations for reactive case detection strategy implementation in a low endemic area of Asutsuare, Ghana.

BACKGROUND: Progress toward malaria elimination is increasing as many countries near zero indigenous malaria cases. In settings nearing elimination, interventions will be most effective at interrupting transmission when targeted at the residual foci of transmission. These foci may be missed due to asymptomatic infections. To solve this problem, the World Health Organization recommends reactive case detection (RACD). This case study was conducted to identify individuals with asymptomatic malaria, their predisposing risk factors and recommend RACD in Asutsuare, Ghana based on literature review and a cross sectional study. METHODS: The study involved a search on PubMed and Google Scholar of literature published between 1st January, 2009-14th August, 2023 using the search terms "malaria" in "Asutsuare". Furthermore, structured questionnaires were administered to one hundred individuals without symptoms of malaria and screened using rapid diagnostic test (RDT) kits, microscopy and real-time polymerase chain reaction (rt-PCR). Malaria prevalence based on the three diagnostic techniques as well as potential malaria risk factors were assessed through questionnaires in a cross-sectional study. RESULTS: Cumulatively, sixty-four (64) studies (Google Scholar, 57 and PubMed, 7) were reviewed and 22 studies included in the literature on malaria in Asutsuare, Ghana. Significant risk factors were occupation, distance from a house to a waterbody, age group and educational level. Out of the 100 samples, 3 (3%) were positive by RDT, 6 (6%) by microscopy and 9 (9%) by rt-PCR. Ages 5-14.9 years had the highest mean malaria parasite densities of 560 parasites/µl with Plasmodium falciparum as the dominant species in 4 participants. Moreover, in the age group ≥ 15, 2 participants (1 each) harboured P. falciparum and Plasmodium malariae parasites. RDT had a higher sensitivity (76.54%; CI95 66.82-85.54) than rt-PCR (33.33%; CI95 4.33-77.72), while both rt-PCR and RDT were observed to have a higher specificity (92.55; CI95 85.26-96.95) and (97.30; CI95 93.87-99.13), respectively in the diagnosis of malaria. CONCLUSION: In Asutsuare, Ghana, a low endemic area, the elimination of malaria may require finding individuals with asymptomatic infections. Given the low prevalence of asymptomatic individuals identified in this study and as repleted in the literature review, which favours RACD, Asutsuare is a possible setting receptive for RACD implementation.

The Effect of Blood Clots on the Quality of RNA Extracted from PAXgene Blood RNA Tubes.

Background: PAXgene® Blood RNA tubes are routinely used in clinical research and molecular biology applications to preserve the stability of RNA in whole blood. However, in practice, blood clots are occasionally observed after blood collection and are often ignored. Currently, there are few studies on whether blood clots affect the quality of RNA extracted from these tubes. Materials and Methods: Fifteen pairs of non-clot and clot PAXgene Blood RNA tube samples (n = 30) were collected to form two matched groups from 15 patients. According to the maximum diameter (d) of the blood clot observed visually at the time of sample reception, the clot groups were divided into a small-clot group (0 cm < d < 0.5 cm) and a large-clot group (d ≥ 0.5 cm). RNA was extracted by the PAXgene Blood RNA Kit. To analyze the quality of RNA, its yield and purity were assessed by spectrophotometry, and integrity was measured by microfluidic electrophoresis. An A260/280 ratio between 1.8 and 2.2 indicated purified RNA, and RNA integrity number (RIN) values ≥7.0 were considered to represent qualified integrity. Results: The median yields of RNA from the non-clot and clot groups were 3.84 (2.80-6.38) µg and 4.87 (2.77-8.30) µg, respectively. The median A260/280 ratios were 2.08 (2.06-2.09) and 2.09 (2.07-2.11), whereas the median A260/230 ratios were 1.77 (1.31-1.91) and 1.67 (1.21-1.94) in the two groups. In addition, the median RINs were 8.20 (8.00-8.40) and 7.20 (6.60-7.70), respectively. There were no significant differences in RNA yields, A260/280, or A260/230 between the two groups. However, the RIN value of the clot group was significantly lower compared with the non-clot group (p < 0.05), with RIN ≥7.0 found in all non-clot samples and 60% of clot samples (p < 0.05). Furthermore, in the clot groups, the small-clot samples had higher RIN values than large-clot samples (8.25 [7.75-8.75] vs. 6.90 [6.60-7.30], p < 0.001). Conclusions: The formation of large blood clots in PAXgene Blood RNA tubes will reduce the integrity of extracted RNA.

Regulation (EU) 2017/746 (IVDR): practical implementation of annex I in pathology.

BACKGROUND: Regulation (EU) 2017/746 on in vitro diagnostic medical devices (IVDR) imposes several conditions on pathology departments that develop and use in-house in vitro diagnostic medical devices (IH-IVDs). However, not all of these conditions need to be implemented immediately after the IVDR entered into force on 26 May 2022. Based on an amending regulation of the European Parliament and the Council of the European Union, the requirements for IH-IVDs will be phased in. Conformity with the essential safety and performance requirements of annex I must be ensured from May 2022. OBJECTIVES: With this article, we would like to present the practical implementation of the currently valid conditions for IH-IVDs at the Institute of Pathology at the University Hospital of Heidelberg, in order to provide possible assistance to other institutions. CONCLUSIONS: In addition to the intensive work on the requirements for IH-IVDs, several guidance documents and handouts provide orientation for the implementation and harmonisation of the requirements for healthcare institutions mentioned in Article 5 (5). Exchange in academic network structures is also of great importance for the interpretation and practical implementation of the IVDR. For university and nonuniversity institutions, ensuring conformity with the IVDR represents a further challenge in terms of personnel and time, in addition to the essential tasks of patient care, teaching and research and the further development of methods for optimal and targeted diagnostics, as well as the maintenance of the constantly evolving quality management system.

"Test-To-PrEP": Assessing Reach and Adoption of a New Approach to Increase HIV Testing and PrEP Knowledge Using HIV Self-Test Kit Distribution Through PrEP Clients' Social Networks.

BACKGROUND: HIV self-testing (HIVST) can increase the reach of HIV testing. Preexposure prophylaxis (PrEP) clients may be ideal distributors of HIVST kits and PrEP information within their social networks. This study uses the Reach, Effectiveness, Adoption, Implementation, and Maintenance framework to evaluate the distribution of HIVST bundled with PrEP information ("Test-to-PrEP" kits) among egocentric friendship networks of PrEP users. METHODS: The study was conducted in Miami from November 2021 to March 2022. Enrolled PrEP clients (egos; n = 100) were offered Test-to-PrEP kits for distribution. Egos and Test-to-PrEP kit users completed brief online surveys. Descriptive statistics are reported for participants, their reported network members, and users of the Test-to-PrEP kits. Logistic and Poisson regression assessed the relationship between characteristics of egos, alters, and the distribution of Test-to-PrEP kits. RESULTS: The 100 enrolled egos reported a total of 414 alters. Participants received 293 Test-to-PrEP kits for distribution with 47 of the 100 participants distributing at least 1 kit. Of those who scanned the quick-response code and responded to the survey, 16.2% reported no previous HIV test and 38.5% reported no prior knowledge of PrEP; 32.5% reported interest in distributing Test-to-PrEP kits, 3 successfully distributed kits, and 2 initiated PrEP. CONCLUSIONS: An approach using PrEP clients' social networks can disseminate HIVST bundled with PrEP information to critical populations including individuals lacking knowledge of PrEP or who have never been tested for HIV. Future studies will assess whether this use of network effects can increase reach and efficiency of HIV testing and PrEP information distribution.

Performance evaluation of the cobas SARS-CoV-2 Duo, a novel qualitative and quantitative assay, for the detection of SARS-CoV-2 RNA.

IMPORTANCE: Quantitative SARS-CoV-2 tests for viral load are necessary to guide patient treatment, as well as to determine infection control measures and policies. Although the real-time RT-PCR assays can report the Ct value to estimate the viral load, there are several serious concerns regarding the use of Ct values. Importantly, Ct values can vary significantly among between- and within-run methods. The diagnostic performance of the cobas SARS-CoV-2 Duo is appropriate. It is a precise, accurate, and sensitive method for the detection of SARS-CoV-2 RNA and is comparable to two qualitative assays (the cobas SARS-CoV-2 and the Liat cobas SARS-CoV-2 and Inf A/B). In contrast, using the Ct value to estimate viral load is not reliable, and utilization of a quantitative detection test, such as the cobas SARS-CoV-2 Duo, to accurately measure the viral load is needed.

Identification of Key Influencers for Secondary Distribution of HIV Self-Testing Kits Among Chinese Men Who Have Sex With Men: Development of an Ensemble Machine Learning Approach.

BACKGROUND: HIV self-testing (HIVST) has been rapidly scaled up and additional strategies further expand testing uptake. Secondary distribution involves people (defined as "indexes") applying for multiple kits and subsequently sharing them with people (defined as "alters") in their social networks. However, identifying key influencers is difficult. OBJECTIVE: This study aimed to develop an innovative ensemble machine learning approach to identify key influencers among Chinese men who have sex with men (MSM) for secondary distribution of HIVST kits. METHODS: We defined three types of key influencers: (1) key distributors who can distribute more kits, (2) key promoters who can contribute to finding first-time testing alters, and (3) key detectors who can help to find positive alters. Four machine learning models (logistic regression, support vector machine, decision tree, and random forest) were trained to identify key influencers. An ensemble learning algorithm was adopted to combine these 4 models. For comparison with our machine learning models, self-evaluated leadership scales were used as the human identification approach. Four metrics for performance evaluation, including accuracy, precision, recall, and F1-score, were used to evaluate the machine learning models and the human identification approach. Simulation experiments were carried out to validate our approach. RESULTS: We included 309 indexes (our sample size) who were eligible and applied for multiple test kits; they distributed these kits to 269 alters. We compared the performance of the machine learning classification and ensemble learning models with that of the human identification approach based on leadership self-evaluated scales in terms of the 2 nearest cutoffs. Our approach outperformed human identification (based on the cutoff of the self-reported scales), exceeding by an average accuracy of 11.0%, could distribute 18.2% (95% CI 9.9%-26.5%) more kits, and find 13.6% (95% CI 1.9%-25.3%) more first-time testing alters and 12.0% (95% CI -14.7% to 38.7%) more positive-testing alters. Our approach could also increase the simulated intervention's efficiency by 17.7% (95% CI -3.5% to 38.8%) compared to that of human identification. CONCLUSIONS: We built machine learning models to identify key influencers among Chinese MSM who were more likely to engage in secondary distribution of HIVST kits. TRIAL REGISTRATION: Chinese Clinical Trial Registry (ChiCTR) ChiCTR1900025433; https://www.chictr.org.cn/showproj.html?proj=42001.