Traditional Swab Research Articles

Capture of Group A Streptococcus by Open-Microfluidic CandyCollect Device in Pediatric Patients.

Obtaining high-quality samples to diagnose streptococcal pharyngitis in pediatric patients is challenging due to discomfort associated with traditional pharyngeal swabs. This may cause reluctance to go to the clinic, inaccurate diagnosis, or inappropriate treatment for children with sore throat. Here, we determined the efficacy of CandyCollect, a lollipop-inspired open-microfluidic pathogen collection device, to capture Group A Streptococcus (GAS) and compare user preference for CandyCollect, conventional pharyngeal swabs, or mouth swabs in children with pharyngitis and their caregivers. All child participants (30/30) were positive for GAS by qPCR on both the mouth swab and CandyCollect. Caregivers ranked CandyCollect as a good sampling method overall (27/30), and all caregivers (30/30) would recommend CandyCollect for children 5 years and older. Twenty-three of 30 children "really like" the taste and 24/30 would prefer to use CandyCollect if a future test were needed. All caregivers (30/30) and most children (28/30) would be willing to use CandyCollect at home. All participants tested positive for GAS on all three collection methods (pharyngeal swab, mouth swab, and CandyCollect). While both caregivers and children like CandyCollect, some caregivers would prefer a shorter collection time. Future work includes additional studies with larger cohorts presenting with pharyngitis of unknown etiology and shortening collection time while maintaining the attractive form of the device. Obtaining oral samples for the diagnosis of streptococcal pharyngitis is of great importance for children. To address the challenges associated with traditional pharyngeal swab sampling, we developed the CandyCollect device, a lollipop-inspired open mesofluidic saliva sampling system. In this study, saliva samples were collected from children, aged 5-14 years, with CandyCollect and mouth swabs and analyzed via qPCR. The results show CandyCollect is the child preferred collection tool and had 100% concordance with the results from traditional diagnosis methods as part of their clinical care.

Diagnostic Value of Saliva RT-PCR Test within Suspected SARS-CoV-2 Cases in Indonesia

Introduction: The ongoing SARS-CoV-2 pandemic has profoundly emphasized the pressing need for accurate and reliable diagnostic procedures. Given the potential health risks associated with nasopharyngeal swabs, there has been growing interest in seeking alternative diagnostic mediums. In this context, our study delved into evaluating saliva as a potential diagnostic tool, simultaneously assessing its efficiency in relation to patient demographics and their exhibited clinical symptoms. Methods: Spanning from May to December 2020, we conducted a comprehensive cross-sectional analysis. We meticulously examined medical records to gather insights on patient characteristics, existing health conditions, onset of symptoms, clinical manifestations, and compared the results obtained from both salivary and nasopharyngeal RT-PCR tests for SARS-CoV-2. Results: Among the individuals suspected of SARS-CoV-2 infection, the mean age stood at 52.4 years, with males representing 60.3% of this group. Interestingly, a significant 76.9% reported underlying health conditions, predominantly hypertension and diabetes. The most commonly reported symptoms encompassed respiratory challenges, notably coughing and shortness of breath, succeeded by symptoms like nausea, fever, and a general sense of fatigue. The performance of saliva tests, in terms of accuracy, appeared to be significantly influenced by the timing of symptom emergence. Conclusion: The RT-PCR tests utilizing saliva samples demonstrated considerable promise, especially during the early stages of symptom manifestation, providing a reliable alternative to traditional nasopharyngeal swabs. The findings suggest a superior diagnostic sensitivity when utilizing saliva during the initial phases of a SARS-CoV-2 infection.

Enhancing detection accuracy via controlled release of 3D-printed microlattice nasopharyngeal swabs

Nasopharyngeal (NP) swab is one of the most effective sampling devices for clinical specimens. However, commercial NP swabs often release samples through diluents, lowering analyte concentration and causing inaccurate detections. Here, we developed 3D-printed open-cell microlattice NP swabs with user-friendly high-efficiency controlled sample release (CR) mode. Compared with traditional NP swabs, our microlattice NP swabs show higher (~7–11 times) flexibility, larger (~2.3 times) and customizable release volume, higher (dozens to thousands of times) release concentration, high recovery efficiency (~100%), and the ability to quantify analyte levels. Our microlattice NP swabs have been thus demonstrated to improve the sensitivity and accuracy of antibody detection experiments using rapid detection kits. This study offers a promising approach to enhance sensitivity and accuracy in clinical specimen detections, and is beneficial to inspire the design of a wider range of biomedical devices based on 3D-printed microlattice metamaterials.

Use of saliva-based qPCR diagnostics for the accurate, rapid, and inexpensive detection of strep throat.

Outpatient health care facilities are essential for quickly diagnosing common infectious diseases such as bacterial and viral pharyngitis. The only form of pharyngitis requiring antibiotics is strep throat (ST); however, antibiotic prescription rates are much higher than ST prevalence, suggesting antibiotics are being inappropriately prescribed. Current rapid ST diagnostics may be contributing to this problem due to the low sensitivity and variable specificity of these tests. It is best practice to verify a negative ST diagnosis with a group A Streptococcus (GAS) culture, but many clinics do not perform this test due to the additional cost and 24-72 h required to obtain results. This indicates there is great need for more accurate rapid diagnostic tools in outpatient facilities. We hypothesized that next generation qPCR technology could be adapted to detect GAS DNA from saliva samples (instead of the traditional throat swab) by creating a simple, fast, and inexpensive protocol. Saliva specimens collected from patients at James Madison University Health Center were used to test the effectiveness of our Chelex 100-based rapid DNA extraction method, followed by a fast protocol developed for the Open qPCR machine to accurately detect ST. Our final saliva processing and qPCR protocol required no specialized training to perform and was able to detect ST with 100 % sensitivity and 100 % specificity (n=102) in 22-26 min, costing only $1.12 per sample. Saliva can be rapidly analyzed via qPCR for the accurate and inexpensive detection of ST.

Tailoring the properties of poly(vinyl alcohol) “twin-chain” gels via sebacic acid decoration

HypothesisThe development of gels capable to adapt and act at the interface of rough surfaces is a central topic in modern science for Cultural Heritage preservation. To overcome the limitations of solvents or polymer solutions, commonly used in the restoration practice, poly(vinyl alcohol) (PVA) “twin–chain” polymer networks (TC-PNs) have been recently proposed. The properties of this new class of gels, that are the most performing gels available for Cultural Heritage preservation, are mostly unexplored. This paper investigates how chemical modifications affect gels’ structure and their rheological behavior, producing new gelled systems with enhanced and tunable properties for challenging applications, not restricted to Cultural Heritage preservation. ExperimentsIn this study, the PVA-TC-PNs structural and functional properties were changed by functionalization with sebacic acid into a new class of TC-PNs. Functionalization affects the porosity and nanostructure of the network, changing its uptake/release of fluids and favoring the uptake of organic solvents with various polarity, a crucial feature to boost the versatility of TC-PNs in practical applications. FindingsThe functionalized gels exhibited unprecedented performances during the cleaning of contemporary paintings from the Peggy Gugghenheim collection (Venice), whose restoration with traditional solvents and swabs would be difficult to avoid possible disfigurements to the painted layers. These results candidate the functionalized TC-PNs as a new, highly promising class of gels in art preservation.

Electrostatic capture of viruses on cationic biopolymer membranes for intra-oral disease sampling

Naso- and oropharyngeal swabs are the Center for Disease Control and Prevention (CDC) -recommended disease sampling methods for respiratory viruses. The short swabbing time for sampling by these methods may lead to variability in test results. Further, these methods are mildly invasive and can cause discomfort, tearing or gag reflexes in tested individuals. If longer sampling time is coupled with lesser patient discomfort, test reliability and patient compliance can be improved. Towards this end, we developed cationic biopolymer membranes for the electrostatic capturing of viruses in the oral cavity. Here, chemically (EDC-NHS) crosslinked uncharged chitosan (CS) nanofiber membranes were conferred either with negative surface charge by anionic poly-aspartic acid (pAsp) coating or positive charge by cationic poly-L-lysine (PLL). Consistent with our preliminary findings of dynamic light scattering (DLS) size measurements showing large agglomerates of anionic virus-like particles (VLPs) and cationic PLL in solution, a 75% increase in VLP adsorption by PLL coated CS membranes was recorded by enzyme linked immunosorbent assay (ELISA), in comparison to untreated controls. It is envisaged that the electrostatic concentration of respiratory viruses on cationic membranes can be superior alternatives to traditional swabbing in the oral cavity.

A comparative study on two methods of ocular surface microbial sampling

PurposeTo compare the effect of traditional conjunctival sac swab sampling (A) with aerosolization ocular surface microorganism sampling (B),a novel microbial sampling method, in detecting ocular microbial infection.MethodsThe study included 61 participants (122 eyes) enrolled at the Eye Hospital, Wenzhou Medical University from December, 2021 to March, 2023. Each eye of the participants underwent sampling first with method A then B.Before aerosolization sampling, the air environment was disinfected and sampled as blank air control sample. Subsequently, the air pulses impinging the ocular surface causes dehiscence of the tear film covering the ocular surface and aerosols are formed.The microorganisms from the ocular surface attach to the aerosols generated as aerosolization ocular surface microorganism and be sampled as subject sample by bio-aerosol sampler.The samples were collected and incubated at 25℃ for 3–5 days and 37℃ for 24–48 h.The colonies were counted and identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.ResultsThe accuracy in Group B was higher than that in Group A (45.8% vs. 38.3%, P = 0.289). There was a slight level of agreement between the results from both the sampling methods (k = 0.031, P = 0.730). The sensitivity in Group B was higher than that in Group A (57.1% vs. 35.7%, P = 0.453). The specificity results in Group B was higher than that in Group A (44.3% vs. 38.7%, P = 0.480). There were 12 and 37 types of microbes detected in Groups A and B, respectively.ConclusionsCompared with traditional swab sampling, the novel aerosolization sampling method shows higher accuracy and more comprehensive detection of microbes; however, it cannot completely replace swab sampling. The novel method can be a novel conducive strategy and supplement swab sampling to auxiliary diagnose ocular surface infection.

Effect of swabbing technique and duration on forensic DNA recovery

Various factors have been shown to affect performance of the conventional wet-dry double and single wet swabbing techniques to recover DNA, such as pressure and angle of application, volume and type of wetting agent, and swab type. However, casework laboratories in some jurisdictions have recently adopted different swabbing techniques that include wet-moist double swabbing and moist-dry single swabbing. Factors affecting the effectiveness of these recent techniques in maximising DNA recovery therefore need to be investigated. Here, the performance of traditional and recent swabbing techniques was compared and the impact of swabbing duration on DNA recovery was investigated. Ten µl aliquots of a known concentration of DNA extracted from human blood were deposited on pre-cleaned DNA-free cotton swatches (porous) and porcelain tiles (non-porous). Five swabbing techniques were used, of which three were double swabbing techniques: wet-moist, wet-wet and wet-dry, and two were single swabbing techniques: wet and moist-dry. For a ‘wet’ or ‘moist’ swab, 100 or 50 µL water was added, respectively. For a moist-dry swab, water was applied to one side of the swab, leaving the other side drier. Each swabbing technique was applied for two durations, 15 and 30 s per swab, with 5 reps of each combination (n = 100 plus controls). All samples were extracted and quantified, and a sub-set was profiled. The results showed that the wet-moist double swabbing technique with a swabbing duration of 30 s maximised DNA recovery from cotton. From tile, a single wet or moist-dry swab maximised DNA recovery, but increasing swabbing duration from 15 to 30 s had no impact. These data can be used to inform standardisation of DNA collection protocols across casework laboratories.

Accurate Diagnosis of COVID-19 from Self-Collectable Biospecimens Using Synthetic Apolipoprotein H Peptide-Coated Nanoparticle Assay.

A high-throughput, accurate screening is crucial for the prevention and control of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Current methods, which involve sampling from the nasopharyngeal (NP) area by medical staffs, constitute a fundamental bottleneck in expanding the testing capacity. To meet the scales required for population-level surveillance, self-collectable specimens can be used; however, its low viral load has hindered its clinical adoption. Here, we describe a magnetic nanoparticle functionalized with synthetic apolipoprotein H (ApoH) peptides to capture, concentrate, and purify viruses. The ApoH assay demonstrates a viral enrichment efficiency of >90% for both SARS-CoV-2 and its variants, leading to an order of magnitude improvement in analytical sensitivity. For validation, we apply the assay to a total of 84 clinical specimens including nasal, oral, and mouth gargles obtained from COVID-19 patients. As a result, a 100% positivity rate is achieved from the patient-collected nasal and gargle samples, which exceeds that of the traditional NP swab method. The simple 12 min pre-enrichment assay enabling the use of self-collectable samples will be a practical solution to overcome the overwhelming diagnostic capacity. Furthermore, the methodology can easily be built on various clinical protocols, allowing its broad applicability to various disease diagnoses.

P-375 Optimising vaginal biospecimen collection

Abstract Study question Are menstrual tampons an acceptable and comparable method to lower vaginal swabs (LVS) for analysing the vaginal microbiome in non-pregnant women? Summary answer Tampons capture a higher bacterial load, volunteers are familiar with them, thus are well-accepted, and can be efficiently frozen at -20 °C prior to analysis. What is known already The vaginal microbiome plays a key role in women’s reproductive health. The application of investigating this niche allows a greater understanding of the impact of the vaginal microbiota in diverse reproductive disorders including infertility, recurrent miscarriage, spontaneous preterm birth and sexually transmitted infections. Fear and embarrassment related to physicians taking a traditional vaginal swab using a speculum results in many female genitourinary health appointments to be missed in the UK and recruitment challenges into vaginal microbiota research studies. Growing evidence suggests a menstrual tampon to be a superior alternative biospecimen collection device to a vaginal swab. Study design, size, duration This was a prospective, cross-sectional observational study. Twenty-one healthy volunteers (average age 30 years) were recruited over a period of 6 weeks at the Centre for Women's Health Research, University of Liverpool, an academic, tertiary referral centre. Participants/materials, setting, methods The volunteers consented to wearing a tampon for 20 minutes, taking 2 LVS and completing an acceptability questionnaire. Samples were halved for immediate processing and freezing at -20 °C for 2-4 weeks. Real-time PCR using Femoflor-16 was carried out to identify microorganisms present in vaginal microbiota. Microbiota was classified by total bacterial mass and relative abundance of lactobacillus species. Statistical analysis was carried out using GraphPad PRISM 5, Microsoft Excel 2019 and IBM SPSS Statistics 27. Main results and the role of chance Of the 84 samples, four had insufficient material for the purpose of analysis. Three of these were LVS samples and the fourth was a frozen tampon sample. Mean tampon total bacterial mass was higher for fresh and frozen samples versus the mean LVS total bacterial mass. The Femoflor algorithm gave identical vaginal microbiota characterisation between the fresh tampon and fresh LVS in 68.4% (13/19) of cases. 92% (12/13) samples with over 80% relative abundance of lactobacillus in the LVS also had over 80% relative abundance in the tampon. More discrepancy was seen between samples within the 20-80% and <20% relative abundance groups of lactobacillus in the LVS with 50% and 75% different classifications respectively. Importantly, only one case showed an LVS with lactobacillus >80% (normal) and a tampon with non-dominance of lactobacillus (<80%, dysbiosis). The questionnaires revealed that 90.5% of the volunteers highly rated using tampons (3 or more out of 5 on a Likert scale), with 52.4% rating tampon-use at 5/5. All participants (100%) stated that they would be happy to provide a tampon sample for clinical/research testing purposes in the future. Limitations, reasons for caution This study included 21 healthy volunteers; this is not necessarily representative of the entire UK population, but the tampon and LVS from the same volunteer were consistently comparable before and after freezing. We used a multiplex PCR assay to target common vaginal bacteria, inevitably some bacteria have not been characterised. Wider implications of the findings Self-collected tampons are suitable, well accepted biospecimen collection devices that may reduce barriers posed due to embarrassment, improve attendance in genitourinary medicine clinics and encourage participation in vaginal microbiota research. Freezing before processing reduces time and costs. A large study is necessary to ensure reproducibility and acceptability to patient population. Trial registration number Not Applicable

CFD based analysis of 3D printed nasopharyngeal swabs for COVID-19 diagnostics

Background and ObjectiveAdditive manufacturing of nasopharyngeal (NP) swabs using 3D printing technology presents a viable alternative to address the immediate shortage problem of standard flock-headed swabs for rapid COVID-19 testing. Recently, several geometrical designs have been proposed for 3D printed NP swabs and their clinical trials are already underway. During clinical testing of the NP swabs, one of the key criteria to compare the efficacy of 3D printed swabs with traditional swabs is the collection efficiency. In this study, we report a numerical framework to investigate the collection efficiency of swabs utilizing the computational fluid dynamics (CFD) approach. MethodsThree-dimensional computational domain comprising of NP swab dipped in the liquid has been considered in this study to mimic the dip test procedure. The volume of fluid (VOF) method has been employed to track the liquid-air interface as the NP swab is pulled out of the liquid. The governing equations of the multiphase model have been solved utilizing finite-volume-based ANSYS Fluent software by imposing appropriate boundary conditions. Taguchi's based design of experiment analysis has also been conducted to evaluate the influence of geometric design parameters on the collection efficiency of NP swabs. The developed model has been validated by comparing the numerically predicted collection efficiency of different 3D printed NP swabs with the experimental findings. ResultsNumerical predictions of the CFD model are in good agreement with the experimental results. It has been found that there prevails huge variability in the collection efficiency of the 3D printed designs of NP swabs available in the literature, ranging from 2 µl to 120 µl. Furthermore, even the smallest alteration in the geometric design parameter of the 3D printed NP swab results in significant changes in the amount of fluid captured. ConclusionsThe proposed framework would assist in quantifying the collection efficiency of the 3D printed designs of NP swabs, rapidly and at a low cost. Moreover, we demonstrate that the developed framework can be extended to optimize the designs of 3D printed swabs to drastically improve the performances of the existing designs and achieve comparable efficacy to that of conventionally manufactured swabs.

Evaluation of Swab-Seq as a scalable, sensitive assay for community surveillance of SARS-CoV-2 infection

The ongoing SARS-CoV-2 pandemic and subsequent demand for viral testing has led to issues in scaling diagnostic lab efforts and in securing basic supplies for collection and processing of samples. This has motivated efforts by the scientific community to establish improved protocols that are more scalable, less resource intensive, and less expensive. One such developmental effort has resulted in an assay called “Swab-Seq”, so named because it was originally developed to work with dry nasal swab samples. The existing gold standard test consists of RNA extracted from a nasopharyngeal (NP) swab that is subjected to quantitative reverse transcription polymerase chain reaction (qRT-PCR). Swab-Seq adapts this method to a next-generation sequencing readout. By pairing this modification with extraction-free sampling techniques, Swab-Seq achieves high scalability, low cost per sample, and a reasonable turnaround time. We evaluated the effectiveness of this assay in a community surveillance setting by testing samples collected from both symptomatic and asymptomatic individuals using the traditional NP swab. In addition, we evaluated extraction-free sampling techniques (both saliva and saline mouth gargle samples). We found the assay to be as clinically sensitive as the qRT-PCR assay, adaptable to multiple sample types, and able to easily accommodate hundreds of samples at a time. We thus provide independent validation of Swab-Seq and extend its utility regarding sample type and sample stability. Assays of this type greatly expand the possibility of routine, noninvasive, repeated testing of asymptomatic individuals suitable for current and potential future needs.

Understanding and optimizing Evolon\xae CR for varnish removal from oil paintings

Evolon^circledR CR is increasingly used in paintings conservation for varnish removal from oil paintings. Its key benefits over traditional cotton swabs are limiting solvent exposure and reducing mechanical action on the paint surface. However, this non-woven microfilament textile was not originally engineered for conservation use and little is known about its chemical stability towards organic solvents. Moreover, the physical processes of solvent loading and release by Evolon^circledR CR, as well as solvent retention inside paint after cleaning, have not been studied. These three topics were investigated using a multi-analytical approach, aiming for an improved understanding and optimized use of Evolon^circledR CR for varnish removal. Our results show that the tissue is generally chemically and physically stable to organic solvents when exposed on timescales that are typical in conservation practice. However, a pre-treatment step of Evolon^circledR CR is necessary to avoid the release of unwanted saturated fatty acids into the paint during varnish removal. We show that the primary mechanism of solvent uptake by the fibers is adsorption rather than absorption and that the dominant factor dictating the maximum solvent load is the volume of the voids between the fibers. Finally, solvent induced dynamics after application of solvent-loaded Evolon^circledR CR within the paint film was monitored using portable laser speckle imaging on model paints. A method to quantify solvent-retention in real-time was developed and revealed that the presence of varnish on paintings results in lower dynamics of solvents within the paint in comparison to unvarnished paint. Comparing various solvents, it was found that cleaning with acetone resulted in a roughly six-fold increase in dynamics compared to ethanol and isopropanol.

Performance of three-dimensional printed nasopharyngeal swabs for COVID-19 testing.

At the start of the COVID-19 pandemic, the US faced nationwide shortages of nasopharyngeal swabs due to both overwhelmed supply chains and an increase in demand. To address this shortfall, multiple 3D printed swabs were ultimately produced and sold for COVID-19 testing. In this work, we present a framework for mechanical and functional bench-testing of nasopharyngeal swabs using standard and widely available material testing equipment. Using this framework, we offer a comprehensive, quantitative comparison of the 3D printed swabs to benchmark their performance against traditional flocked swabs. The test protocols were designed to emulate the clinical use of the nasopharyngeal swabs and to evaluate potential failure modes. Overall, the 3D printed swabs performed comparably to, or outperformed, the traditional swabs in all mechanical tests. While traditional swabs outperformed some of the new 3D printed swabs in terms of sample uptake and retention, similar amounts of RNA were recovered from both 3D printed and traditional swabs.Graphic abstract

Collection and storage of DVI samples with microFLOQ® Direct swabs for direct amplification

The rapid identification of decomposing human remains is a crucial component of disaster victim identification (DVI), often occurring in remote areas without access to laboratory or storage facilities. Due to the ease of collection and amenability to storage in harsh conditions, swabs may be used to collect DNA from decomposing remains as an alternative to sampling tissue or bone. Direct amplification could further streamline the process and reduce costs. This study investigated the efficacy of direct amplification of DVI samples using microFLOQ® Direct swabs and the QIAGEN Investigator QS GO! Kit. A comparison of performance between direct amplification and traditional methods was made to assess whether direct amplification offered an improvement to traditional methods. DNA was collected by swabbing the muscle of a decomposing human cadaver using three swab types (ADS Genetics 4N6FLOQSwabs®, NADS Genetics 4N6FLOQSwabs®, and the microFLOQ® Direct swab). Traditional swabs (4N6FLOQSwabs®) were extracted and quantified, while a direct amplification strategy was used with the microFLOQ® Direct swabs coupled with the Investigator 24Plex GO! Kit. Processing of the microFLOQ® Direct swabs were optimized and a hybrid strategy that used 4N6FLOQSwabs® to collect and store DNA before swabbing or “subsampling” the 4N6FLOQSwabs® for processing with microFLOQ® Direct swabs was developed. This hybrid strategy allowed for rapid processing without the consumption of the original sample. Traditional and direct PCR methods were comparable up to day 10 of decomposition depending on the sample location and for up to 3 months of storage at room temperature. This research indicated that microFLOQ® Direct swabs in conjunction with the Investigator 24Plex GO! Kit can be used to facilitate rapid direct processing of DNA from decomposing human remains.

A Severe Acute Respiratory Syndrome Coronavirus 2 detection method based on nasal and nasopharyngeal lavage fluid: A pilot feasibility study.

ObjectiveNose and nasopharyngeal swab is the preferred and worldwide‐accepted method to detect the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS‐CoV‐2) within the nose and nasopharynx. This method may be linked with possible difficulties, such as patient's discomfort or complications. This article shows a pilot study of SARS‐CoV‐2 detection with nasal and nasopharyngeal lavage fluids (level of evidence: 3).MethodsNasal lavage fluid was collected from patients who were submitted to SARS‐CoV‐2 screening test, due to a preceding positive rapid antigen test. A control group was enrolled among health care professionals whose nasopharyngeal swab tested negative. Nasal lavages were performed using isotonic saline solution injected through a nasal fossa. Both lavage fluid and traditional nasopharyngeal swab were analyzed by real‐time (RT) PCR and antigenic test.ResultsA total of 49 positive subjects were enrolled in the study. Results of the analysis on lavages and nasopharyngeal swabs were concordant for 48 cases, regardless of the antigenic and molecular test performed. RT‐PCR resulted weakly positive at swab in one case and negative at lavage fluid. Among the control group (44 subjects), nasopharyngeal swab and lavage fluid analyses returned a negative result. Sensitivity of the molecular test based on nasal lavage fluid, compared to traditional nasal swab, was 97.7%, specificity was 100%, and accuracy was 98.9%, with high agreement (Cohen's κ, 0.978).ConclusionNasal and nasopharyngeal lavages resulted to be highly reliable and well tolerated. A larger series is needed to confirm these results. This approach may potentially represent a valid alternative to the traditional swab method in selected cases.Level of Evidence3.

Reliable detection of SARS-CoV-2 with patient-collected swabs and saline gargles: A three-headed comparison on multiple molecular platforms

With increasing demands for SARS-CoV-2 testing, as well as the shortages for testing supplies, collection devices, and trained healthcare workers (HCWs) to collect specimens, self-collection is an attractive prospect to reduce the need for HCWs and expenditure of personal protective equipment. Apart from the traditional nasopharyngeal swab used for SARS-CoV-2 detection, alternative specimens have been validated such as a combined swabs of the oropharynx and anterior nares (OP/N), or throat samples using saline gargles. Both the alternative specimen types are amenable to self-collection. Objectives. This study aimed to compare the sensitivity of HCW-collected (OP/N) swabs, self-collected OP/N swabs, and self-collected saline gargles. Among 38 individuals previously testing positive for SARS-CoV-2 (or their close contacts), two self-collected specimen types (OP/N and saline gargles) were compared to HCW-collected OP/N swabs. SARS-CoV-2 testing was performed on three molecular assays: a laboratory-developed test (LDT), and two commercial assays on automated platforms: Cobas 6800 (Roche Diagnostics) and Panther (Hologic). The sensitivity of self-collected OP/N swabs was equivalent to healthcare worker (HCW)-collected OP/N swabs at 100.0 % [92.6%–100.0%] for all three molecular tests. The sensitivity of saline gargles was not significantly different than HCW-collected OP/N swabs, but varied slightly between instruments at 93.8 % [85.9%–93.8%] for the LDT, 96.8 % [88.6%–96.8%] for the Cobas assay, and 96.7 % [89.2%–96.9%] for the Panther assay. Overall, self-collection using OP/N swabs or saline gargles are reasonable alternatives to HCW-based collections for SARS-CoV-2 detection, and could facilitate broader surveillance strategies.

384 Use of A Dry Swab During ACL Hamstring Tendon Graft Preparation May Lead to Decreased Graft Diameter at Implantation with Subsequent Rebound in Graft Diameter When Exposed to Haemarthrosis – A Porcine Tendon Study

Abstract Introduction ACL reconstruction surgery commonly utilises a hamstring tendon graft. Grafts are normally covered with a wet swab prior to implantation. The aim of this study was to determine the variance in graft diameter when comparing the traditional wet swab to a dry swab. Method Flexor tendons from a selection of fresh pig trotters were isolated and prepared with a standard ACL graft preparation technique. Half of the grafts were covered with a wet swab; the other half were covered with a dry swab. Graft diameters were measured at 10-minute intervals. After 30 minutes the grafts were submerged in Hartmann’s solution to simulate the post-operative haemarthrosis, diameters were checked again after 1 hour in the solution. Results Use of a dry swab resulted in a 0.5mm greater reduction in diameter than the wet swab group. The dry swab group also showed an increase in diameter by 0.5mm when soaked in Hartmann’s solution, this was not seen in the wet swab group. Conclusions Using a dry swab produces a smaller graft diameter, this would allow smaller bone tunnels, retaining bone stock. The subsequent rebound in diameter when in solution may increase the press fit mechanism and facilitate improved integration into the bone tunnel.

Deployable Telescopic Tubular Mechanisms With a Steerable Tongue Depressor Towards Self-Administered Oral Swab.

Swabbing tests have proved to be an effective method of diagnosis for a wide range of diseases. Potential occupational health hazards and reliance on healthcare workers during traditional swabbing procedures can be mitigated by self-administered swabs. Hence, we report possible methods to apply closed kinematic chain theory to develop a self-administered viral swab to collect respiratory specimens. The proposed sensorized swab models utilizing hollow polypropylene tubes possess mechanical compliance, simple construction, and inexpensive components. In detail, the adaptation of the slider-crank mechanism combined with concepts of a deployable telescopic tubular mechanical system is explored through four different oral swab designs. A closed kinematic chain on suitable material to create a developable surface allows the translation of simple two-dimensional motion into more complex multi-dimensional motion. These foldable telescopic straws with multiple kirigami cuts minimize components involved in the system as the characteristics are built directly into the material. Further, it offers a possibility to include soft stretchable sensors for realtime performance monitoring. A variety of features were constructed and tested using the concepts above, including 1) tongue depressor and cough/gag reflex deflector; 2) changing the position and orientation of the oral swab when sample collection is in the process; 3) protective cover for the swabbing bud; 4) a combination of the features mentioned above.

3D printed auxetic nasopharyngeal swabs for COVID-19 sample collection

The COVID-19 pandemic has resulted in worldwide shortages of nasopharyngeal swabs required for sample collection. While the shortages are becoming acute due to supply chain disruptions, the demand for testing has increased both as a prerequisite to lifting restrictions and in preparation for the second wave. One of the potential solutions to this crisis is the development of 3D printed nasopharyngeal swabs that behave like traditional swabs. However, the opportunity to digitally conceive and fabricate swabs allows for design improvements that can potentially reduce patient pain and discomfort. The study reports the progress that has been made on the development of auxetic nasopharyngeal swabs that can shrink under axial resistance. This allows the swab to navigate through the nasal cavity with significantly less stress on the surrounding tissues. This is achieved through systematically conceived negative Poisson's ratio (−υ) structures in a biocompatible material. Finite element (FE) and surrogate modelling techniques were employed to identify the most optimal swab shape that allows for the highest negative strain (−εlat) under safe stress (σvon). The influence and interaction effects of the geometrical parameters on the swab's performance were also characterised. The research demonstrates a new viewpoint for the development of functional nasopharyngeal swabs that can be 3D printed to reduce patient discomfort. The methodology can be further exploited to address various challenges in biomedical devices and redistributed manufacturing.