Utility of rehabilitation prior to bronchoscopic lung volume reduction: post hoc analysis of the VENT trial.

Background and objective: Rehabilitation programmes are a valuable treatment modality for patients with COPD to increase exercise capacity and quality of life. The utility of pulmonary rehabilitation prior to bronchoscopic lung volume reduction (BLVR) is unclear. Methods: We performed a post hoc analysis of the Valve for Emphysema Palliation Trial (VENT) trial, the first multicentre randomised trial comparing the safety and efficacy of BLVR. Patients completed a pulmonary rehabilitation programme prior to BLVR over 6-10 weeks and maintained by daily practice, consisting of endurance training, strength training and upper/lower limb exercise. Lung function and exercise parameters (6-min walk distance (6MWD)) were assessed before and after rehabilitation and we tried to identify predictors for pulmonary rehabilitation benefit. Results: Lung function and exercise capacity of 403 patients (mean±sd age 63.3±7.4 years, 37.5% female, mean±sd forced expiratory volume in 1 s 30.1±7.6 L) were analysed. Exercise capacity significantly improved from 331.6±98.8 m to 345.6±95.3 m (p<0.001) in 6-min walk testing (6MWT), with 40.3% showing clinically meaningful improvements. Patients also experienced less dyspnoea after 6MWT, while pulmonary function parameters did not change significantly overall. Patients with lower exercise capacity at screening (6MWD <250 m) benefited more from pulmonary rehabilitation. The indication and prerequisites for BLVR were still present in all patients after pulmonary rehabilitation. Conclusion: The national mandatory requirements for rehabilitation prior to BLVR, which apply to all COPD patients, should be reconsidered and specified for COPD patients who really benefit.

Endobronchial lung volume reduction with valves reduces exacerbations in severe emphysema patients.

BACKGROUND AND OBJECTIVE: Exacerbations drive the progression of chronic obstructive pulmonary disease (COPD). Endoscopic lung volume reduction (ELVR) with valves is an established treatment option for patients with severe emphysema. Post-interventional exacerbations are observed in 8-17% of cases. Whether the exacerbation rate changes in the medium term after ELVR, is not known. METHODS: This is a single-center retrospective analysis of severe emphysema patients with endobronchial valve implantation. The number of exacerbations before and after ELVR was compared, including lung function parameters, exercise capacity and degree of lung volume reduction. The primary endpoint of the study was the number of exacerbations one year after ELVR compared to one year before ELVR. RESULTS: 129 patients (mean age 64.1 ± 7.7 years, 57% female, mean FEV1 0.8 ± 0.2 l, mean RV 243.4 ± 54.9 %) with ELVR in the years 2016-2019 and complete exacerbation history were analyzed. Patients experienced a mean of 2.5 ± 2.2 moderate and severe exacerbations in the year before ELVR. The number of exacerbations decreased significantly to 1.8 ± 2.2 exacerbations in the first year after ELVR (p = 0.009). The decrease in exacerbation rate was associated with the development of complete lobar atelectasis (r = 0.228. p = 0.009). Accordingly, in 41 patients with complete lobar atelectasis, the decrease in exacerbation rate was higher from 2.8 ± 2.0 to 1.4 ± 1.8 exacerbations (p < 0.001). CONCLUSIONS: ELVR with valves appears promising to reduce the exacerbation rate in COPD patients, especially when the full treatment benefit of complete lobar atelectasis is achieved.

Endobronchial Valve Replacements in Patients with Advanced Emphysema After Endoscopic Lung Volume Reduction.

Purpose: Up to 41% of patients with endobronchial valve implantation need revision bronchoscopies and valve replacements most likely due to valve dysfunction or lack of benefit. So far, no data is available whether valve replacements lead to the desired lobar volume reduction and therapy benefit. Patients and Methods: We conducted a single-center retrospective analysis of patients with endobronchial valve implantation and at least one valve replacement. Indications and number of revision bronchoscopies and valve replacements were evaluated. Therapy benefit regarding lung function and exercise capacity as well as development of complete lobar atelectasis was investigated and possible predictors identified. Results: We identified 73 patients with 1-12 revision bronchoscopies and 1-5 valve replacements. The main indication for revision bronchoscopy in this group was lack of therapy benefit (44.2%). Lung function and exercise capacity showed improvements in about one-third of patients even years after the initial implantation. A total of 26% of all patients showed a complete lobar atelectasis at the end of the observation period, 56.2% had developed lung volume reduction. The logistic regression revealed the development of a previous complete lobar atelectasis as predictor for a complete lobar atelectasis at final follow-up. Oral cortisone long-term therapy was also shown as predictive factor. The probability for a final complete lobar atelectasis was 69.2% if a lobar atelectasis had developed before. Conclusion: Valve replacements are more likely to be beneficial in patients who develop a re-aeration of a previous lobar atelectasis following valve implantation. Every decision for revision bronchoscopy must be taken carefully.

Multicenter Diagnostic Evaluation of OnSite COVID-19 Rapid Test (CTK Biotech) among Symptomatic Individuals in Brazil and the United Kingdom.

The COVID-19 pandemic has given rise to numerous commercially available antigen rapid diagnostic tests (Ag-RDTs). To generate and to share accurate and independent data with the global community requires multisite prospective diagnostic evaluations of Ag-RDTs. This report describes the clinical evaluation of the OnSite COVID-19 rapid test (CTK Biotech, CA, USA) in Brazil and the United Kingdom. A total of 496 paired nasopharyngeal (NP) swabs were collected from symptomatic health care workers at Hospital das Clínicas in São Paulo, Brazil, and 211 NP swabs were collected from symptomatic participants at a COVID-19 drive-through testing site in Liverpool, United Kingdom. Swabs were analyzed by Ag-RDT, and results were compared to quantitative reverse transcriptase PCR (RT-qPCR). The clinical sensitivity of the OnSite COVID-19 rapid test in Brazil was 90.3% (95% confidence interval [CI], 75.1 to 96.7%) and in the United Kingdom was 75.3% (95% CI, 64.6 to 83.6%). The clinical specificity in Brazil was 99.4% (95% CI, 98.1 to 99.8%) and in the United Kingdom was 95.5% (95% CI, 90.6 to 97.9%). Concurrently, analytical evaluation of the Ag-RDT was assessed using direct culture supernatant of SARS-CoV-2 strains from wild-type (WT), Alpha, Delta, Gamma, and Omicron lineages. This study provides comparative performance of an Ag-RDT across two different settings, geographical areas, and populations. Overall, the OnSite Ag-RDT demonstrated a lower clinical sensitivity than claimed by the manufacturer. The sensitivity and specificity from the Brazil study fulfilled the performance criteria determined by the World Health Organization, but the performance obtained from the UK study failed to do. Further evaluation of Ag-RDTs should include harmonized protocols between laboratories to facilitate comparison between settings. IMPORTANCE Evaluating rapid diagnostic tests in diverse populations is essential to improving diagnostic responses as it gives an indication of the accuracy in real-world scenarios. In the case of rapid diagnostic testing within this pandemic, lateral flow tests that meet the minimum requirements for sensitivity and specificity can play a key role in increasing testing capacity, allowing timely clinical management of those infected, and protecting health care systems. This is particularly valuable in settings where access to the test gold standard is often restricted.

Performance of T-Track® TB, a Novel Dual Marker RT-qPCR-Based Whole-Blood Test for Improved Detection of Active Tuberculosis.

Tuberculosis (TB) is one of the leading causes of death by an infectious disease. It remains a major health burden worldwide, in part due to misdiagnosis. Therefore, improved diagnostic tests allowing the faster and more reliable diagnosis of patients with active TB are urgently needed. This prospective study examined the performance of the new molecular whole-blood test T-Track® TB, which relies on the combined evaluation of IFNG and CXCL10 mRNA levels, and compared it to that of the QuantiFERON®-TB Gold Plus (QFT-Plus) enzyme-linked immunosorbent assay (ELISA). Diagnostic accuracy and agreement analyses were conducted on the whole blood of 181 active TB patients and 163 non-TB controls. T-Track® TB presented sensitivity of 94.9% and specificity of 93.8% for the detection of active TB vs. non-TB controls. In comparison, the QFT-Plus ELISA showed sensitivity of 84.3%. The sensitivity of T-Track® TB was significantly higher (p < 0.001) than that of QFT-Plus. The overall agreement of T-Track® TB with QFT-Plus to diagnose active TB was 87.9%. Out of 21 samples with discordant results, 19 were correctly classified by T-Track® TB while misclassified by QFT-Plus (T-Track® TB-positive/QFT-Plus-negative), and two samples were misclassified by T-Track® TB while correctly classified by QFT-Plus (T-Track® TB-negative/QFT-Plus-positive). Our results demonstrate the excellent performance of the T-Track® TB molecular assay and its suitability to accurately detect TB infection and discriminate active TB patients from non-infected controls.

Bronchoscopic Measurement of Collateral Ventilation: State of the Art.

Endoscopic lung volume reduction procedure with valves is a well-studied treatment option for advanced lung emphysema to target lung hyperinflation in carefully selected patients with COPD. Before valve implantation, collateral ventilation (CV) of the target lobe needs to be assessed to obtain an optimal treatment effect. The analysis of CV according to current standards occurs via an in vivo assessment with the Chartis®system (PulmonX Inc., Redwood City, CA, USA) and a computed tomography (CT) scan of the thorax with interlobar fissure analysis. The focus of this review is to provide detailed information about the Chartis®procedure and interpretation of Chartis® phenotypes. As a main tool in the assessment of CV and being a safe procedure, the Chartis® assessment should be performed by default to confirm interlobar fissure analysis in most emphysema patients. Based on the obtained results, lung volume reduction therapy options should be discussed in an interdisciplinary emphysema conference.

Pooling of sputum samples to increase tuberculosis diagnostic capacity in Brazil during the COVID-19 pandemic.

OBJECTIVES: We assessed whether combining (pooling) four individual's samples and testing with Xpert Ultra has the same accuracy as testing samples individually as a more efficient testing method. METHODS: We conducted a cross-sectional study of individuals with presumptive tuberculosis attending primary health care or general hospital facilities in Alagoas, Brazil. The sputum samples of four consecutive individuals were pooled and the pool and individual samples were tested with Xpert Ultra. The agreement of the tests was compared using kappa statistics. We estimated the sensitivity and specificity of pooling using the individual test as the reference standard and potential cartridge savings. RESULTS: A total of 396 participants were tested. A total of 95 (24.0%) individual samples were Mycobacterium tuberculosis (MTB)-positive, 300 (75.8%) "MTB not detected", including 20 "MTB trace", and one reported an error. A total of 99 pools of four samples were tested, of which 62 (62.6%) had MTB detected and 37 (37.4%) MTB not detected, including six (6.1%) with MTB trace. The agreement between individual and pooled testing was 96.0%. Pooling had a sensitivity of 95.0% (95% confidence interval 86.9-99%), specificity of 97.1% (95% confidence interval 85.1-99.9%), and kappa of 0.913. The method saved 12.4% of cartridge costs. CONCLUSION: The pooled testing of specimens had a high level of agreement with individual testing. The pooling of samples for testing improves the efficiency of testing, potentially enabling the screening and testing of larger numbers of individuals more cost-effectively.

Transbronchial needle aspiration combined with cryobiopsy in the diagnosis of mediastinal diseases: a multicentre, open-label, randomised trial.

BACKGROUND: Transbronchial mediastinal cryobiopsy is a novel sampling technique for mediastinal disease. Despite the possibility of lung cancer misdiagnosis, the improved diagnostic yield of this approach for non-lung-cancer lesions compared with standard endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) highlights its diagnostic potential as a complementary technique to conventional biopsy. We aimed to evaluate the safety profile and added value of the combined use of transbronchial mediastinal cryobiopsy and standard EBUS-TBNA for the diagnosis of mediastinal diseases. METHODS: We conducted an open-label, randomised trial at three hospital sites in Europe and Asia. Eligible patients were aged 15 years or older, with at least one mediastinal lesion of 1 cm or longer in the short axis that required diagnostic bronchoscopy. Participants were randomly assigned (1:1) using a block randomisation scheme generated by a computer (block size of four participants based on a random table from an independent statistician) to the combined use of EBUS-TBNA and transbronchial mediastinal cryobiopsy (combined group) or EBUS-TBNA alone (control group). Because of the nature of the intervention, neither participants nor investigators were masked to group assignment. The coprimary outcomes were differences in procedure-related complications and diagnostic yield (defined as the proportion of participants for whom mediastinal biopsy led to a definitive diagnosis), assessed in the full analysis set, including all the patients who met the eligibility criteria and had a biopsy. A fully paired, intraindividual diagnostic analysis in participants who had both needle aspiration and mediastinal cryobiopsy was conducted, in addition to interindividual comparisons. This trial is now complete and is registered with ClinicalTrials.gov, NCT04572984. FINDINGS: Between Oct 12, 2020, and Sept 9, 2021, 297 consecutive patients were assessed for eligibility and 271 were enrolled and randomly assigned to the combined group (n=136) or the control group (n=135). The addition of cryobiopsy to standard sampling significantly increased the overall diagnostic yield for mediastinal lesions, as shown by both interindividual (126 [93%] of 136 participants in the combined group vs 109 [81%] of 135 in the control group; risk ratio [RR] 1·15 [95% CI 1·04-1·26]; p=0·0039) and intraindividual (126 [94%] of 134 vs 110 [82%] of 134; RR 1·15 [95% CI 1·05-1·25]; p=0·0026) analyses. In subgroup analyses in the intraindividual population, diagnostic yields were similar for mediastinal metastasis (68 [99%] of 69 participants in the combined group vs 68 [99%] of 69 in the control group; RR 1·00 [95% CI 0·96-1·04]; p=1·00), whereas the combined approach was more sensitive than standard needle aspiration in benign disorders (45 [94%] of 48 vs 32 [67%] of 48; RR 1·41 [95% CI 1·14-1·74]; p=0·0009). The combined approach also resulted in an improved suitability of tissue samples for molecular and immunological analyses of non-small-cell lung cancer. The incidence of adverse events related to the biopsy procedure did not differ between trial groups, as grade 3-4 airway bleeding occurred in three (2%) patients in the combined group and two (1%) in the control group (RR 0·67 [95% CI 0·11-3·96]; p=1·00). There were no severe complications causing death or disability. INTERPRETATION: The addition of mediastinal cryobiopsy to standard EBUS-TBNA resulted in a significant improvement in diagnostic yield for mediastinal lesions, with a good safety profile. These data suggest that this combined approach is a valid first-line diagnostic tool for mediastinal diseases. FUNDING: National Natural Science Foundation of China.

Multicenter Diagnostic Evaluation of a Novel Coronavirus Antigen Lateral Flow Test among Symptomatic Individuals in Brazil and the United Kingdom.

The COVID-19 pandemic has led to the commercialization of many antigen-based rapid diagnostic tests (Ag-RDTs), requiring independent evaluations. This report describes the clinical evaluation of the Novel Coronavirus 2019-nCoV Antigen Test (Colloidal Gold) (Beijing Hotgen Biotech Co., Ltd.), at two sites within Brazil and one in the United Kingdom. The collected samples (446 nasal swabs from Brazil and 246 nasopharyngeal samples from the UK) were analyzed by the Ag-RDT and compared to reverse transcription-quantitative PCR (RT-qPCR). Analytical evaluation of the Ag-RDT was performed using direct culture supernatants of SARS-CoV-2 strains from the wild-type (B.1), Alpha (B.1.1.7), Delta (B.1.617.2), Gamma (P.1), and Omicron (B.1.1.529) lineages. An overall sensitivity and specificity of 88.2% (95% confidence interval [CI], 81.3 to 93.3) and 100.0% (95% CI, 99.1 to 100.0), respectively, were obtained for the Brazilian and UK cohorts. The analytical limit of detection was determined as 1.0 × 103 PFU/mL (Alpha), 2.5 × 102 PFU/mL (Delta), 2.5 × 103 PFU/mL (Gamma), and 1.0 × 103 PFU/mL (Omicron), giving a viral copy equivalent of approximately 2.1 × 104 copies/mL, 9.0 × 105 copies/mL, 1.7 × 106 copies/mL, and 1.8 × 105 copies/mL for the Ag-RDT, respectively. Overall, while a higher sensitivity was claimed by the manufacturers than that found in this study, this evaluation finds that the Ag-RDT meets the WHO minimum performance requirements for sensitivity and specificity of COVID-19 Ag-RDTs. This study illustrates the comparative performance of the Hotgen Ag-RDT across two global settings and considers the different approaches in evaluation methods. IMPORTANCE Since the beginning of the SARS-CoV-2 pandemic, we have witnessed growing numbers of antigen rapid diagnostic tests (Ag-RDTs) being brought to market. In the United Kingdom, this was somewhat controlled indirectly as the government offered free tests from a small number of companies. However, as this has now ceased, individuals are responsible for their own acquisition of test kits. Similarly in Brazil, as of January 2022, pharmacies and other health care retailers are permitted to sell Ag-RDTs directly to the community. Many of these Ag-RDTs have not been externally evaluated, and results are not readily available to the public. Thus, there is now a need for a transparent evaluation of Ag-RDTs with both analytical and clinical evaluation. We present an independent review of the Novel Coronavirus 2019-nCoV Antigen Test (Colloidal Gold) (Beijing Hotgen Biotech Co., Ltd.), at two sites within Brazil and one in the United Kingdom.

Endoscopic Valve Therapy in COPD Patients with Hypercapnia.

BACKGROUND: Endoscopic valve therapy has been established as a therapeutic option for patients with severe emphysema. Several randomized controlled trials confirmed the efficacy of this therapeutic approach in COPD patients without significant collateral ventilation. However, patients with clinical relevant hypercapnia were excluded from these trials. AIMS AND OBJECTIVES: Patients with hypercapnia who underwent endoscopic valve treatment were enrolled in this retrospective analysis. The efficacy of valve treatment and its impact on blood gases were analysed. METHODS: COPD patients with mild to severe hypercapnia (pCO2 ≥45 mm Hg) who were treated by endoscopic valve placement at the Thoraxklinik, University of Heidelberg, were enrolled in this retrospective trial. Lung function test (vital capacity [VC], forced expiratory volume in 1 s [FEV1], residual volume [RV]), blood gases (pO2, pCO2), and 6-minute-walk test (6-MWT) were assessed prior to intervention and at 3 and 6 months following valve implantation. RESULTS: 129 patients (mean age 64 ± 7 years) with severe COPD (mean FEV1 26 ± 12% of predicted, mean RV 285 ± 22% of predicted) with hypercapnia (pCO2 ≥45 mm Hg, mean pCO2 50 ± 5 mm Hg) underwent endoscopic valve treatment. 3 and 6 months following intervention, statistical significant improvement was observed in VC, FEV1, RV, and 6-MWT (all p < 0.001). Blood gas analysis revealed a significant improvement of mean pCO2 at 3- and 6-month follow-up (both p < 0.001). 40% of the patients had normal pCO2 values 3 and 6 months following intervention. CONCLUSION: COPD patients with hypercapnia should not be excluded from valve treatment, as the hyperinflation reduction improves the respiratory mechanics and thus leading to improvement of hypercapnia.

Analytical evaluation of thirty-two severe acute respiratory syndrome 2 lateral flow antigen tests demonstrates sensitivity remains with the SARS-CoV-2 Gamma lineage.

BACKGROUND: The emergence of variants of concern (VOCs) requires an ongoing assessment of the performance of antigen lateral flow tests (Ag-RDTs). The limit of detection (LOD) of 32 Ag-RDTs was evaluated using the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Gamma variant. METHODS: Ag-RDTs were performed according to the manufacturer's instructions with a clinical isolate of the Gamma variant. RESULTS: Twenty-eight of the 32 Ag-RDTs exceeded the World Health Organization criteria. CONCLUSIONS: This comprehensive analytical evaluation of Ag-RDTs demonstrated that the test performance was maintained with Gamma VOC.

Endoscopic Options for Moderate COPD, Chronic Bronchitis, and Uncontrolled Asthma.

Until now, interventional therapies for patients with chronic obstructive pulmonary disease have been available in the form of lung volume reduction procedures as end-stage options. Currently, the range of indications is expanding to include earlier stages of the diseases. Lung denervation is available for moderate COPD, and patients with chronic bronchitis are being evaluated for endoscopic goblet cell ablation. Rheoplasty, metered spray cryo technique, and Karakoca resector balloon are used for this indication. But also, for patients with severe uncontrolled asthma, several techniques are available today. In addition to thermoplasty as a long-proven procedure, new and currently under investigation is the targeted lung denervation.Most of these techniques are currently being tested in large pivotal trials and it will soon become clear in which phenotype which technique will be used in the different forms and stages of obstructive diseases. The current paper presents the techniques and the currently available literature.

Differentiating COPD and asthma using quantitative CT imaging and machine learning.

BACKGROUND: There are similarities and differences between chronic obstructive pulmonary disease (COPD) and asthma patients in terms of computed tomography (CT) disease-related features. Our objective was to determine the optimal subset of CT imaging features for differentiating COPD and asthma using machine learning. METHODS: COPD and asthma patients were recruited from Heidelberg University Hospital (Heidelberg, Germany). CT was acquired and 93 features were extracted: percentage of low-attenuating area below -950 HU (LAA950), low-attenuation cluster (LAC) total hole count, estimated airway wall thickness for an idealised airway with an internal perimeter of 10 mm (Pi10), total airway count (TAC), as well as airway inner/outer perimeters/areas and wall thickness for each of five segmental airways, and the average of those five airways. Hybrid feature selection was used to select the optimum number of features, and support vector machine learning was used to classify COPD and asthma. RESULTS: 95 participants were included (n=48 COPD and n=47 asthma); there were no differences between COPD and asthma for age (p=0.25) or forced expiratory volume in 1 s (p=0.31). In a model including all CT features, the accuracy and F1 score were 80% and 81%, respectively. The top features were: LAA950, outer airway perimeter, inner airway perimeter, TAC, outer airway area RB1, inner airway area RB1 and LAC total hole count. In the model with only CT airway features, the accuracy and F1 score were 66% and 68%, respectively. The top features were: inner airway area RB1, outer airway area LB1, outer airway perimeter, inner airway perimeter, Pi10, TAC, airway wall thickness RB1 and TAC LB10. CONCLUSION: COPD and asthma can be differentiated using machine learning with moderate-to-high accuracy by a subset of only seven CT features.

Pooled testing of sputum with Xpert MTB/RIF and Xpert Ultra during tuberculosis active case finding campaigns in Lao People's Democratic Republic.

INTRODUCTION: Active case finding (ACF) of individuals with tuberculosis (TB) is a key intervention to find the 30% of people missed every year. However, ACF requires screening large numbers of individuals who have a low probability of positive results, typically <5%, which makes using the recommended molecular tests expensive. METHODS: We conducted two ACF surveys (in 2020 and 2021) in high TB burden areas of Lao PDR. Participants were screened for TB symptoms and received a chest X-ray. Sputum samples of four consecutive individuals were pooled and tested with Xpert Mycobacterium tuberculosis (MTB)/rifampicin (RIF) (Xpert-MTB/RIF) (2020) or Xpert-Ultra (2021). The agreement of the individual and pooled samples was compared and the reasons for discrepant results and potential cartridge savings were assessed. RESULTS: Each survey included 436 participants, which were tested in 109 pools. In the Xpert-MTB/RIF survey, 25 (sensitivity 89%, 95% CI 72.8% to 96.3%) of 28 pools containing MTB-positive samples tested positive and 81 pools containing only MTB-negative samples tested negative (specificity 100%, 95% CI 95.5% to 100%). In the Xpert-Ultra survey, all 32 (sensitivity 100%, 95% CI 89.3% to 100%) pools containing MTB-positive samples tested positive and all 77 (specificity 100%, 95% CI 95.3% to 100%) containing only MTB-negative samples tested negative. Pooling with Xpert-MTB/RIF and Xpert-Ultra saved 52% and 46% (227/436 and 199/436, respectively) of cartridge costs alone. CONCLUSION: Testing single and pooled specimens had a high level of agreement, with complete concordance when using Xpert-Ultra. Pooling samples could generate significant cartridge savings during ACF campaigns.

Twelve lateral flow immunoassays (LFAs) to detect SARS-CoV-2 antibodies.

BACKGROUND: There are an abundance of commercially available lateral flow assays (LFAs) that detect antibodies to SARS-CoV-2. Whilst these are usually evaluated by the manufacturer, externally performed diagnostic accuracy studies to assess performance are essential. Herein we present an evaluation of 12 LFAs. METHODS: Sera from 100 SARS-CoV-2 reverse-transcriptase polymerase chain reaction (RT-PCR) positive participants were recruited through the FASTER study. A total of 105 pre-pandemic sera from participants with other infections were included as negative samples. RESULTS: At presentation sensitivity against RT-PCR ranged from 37.4 to 79% for IgM/IgG, 30.3-74% for IgG, and 21.2-67% for IgM. Sensitivity for IgM/IgG improved ≥ 21 days post symptom onset for 10/12 tests. Specificity ranged from 74.3 to 99.1% for IgM/IgG, 82.9-100% for IgG, and 75.2-98% for IgM. Compared to the EuroImmun IgG enzyme-linked immunosorbent assay (ELISA), sensitivity and specificity ranged from 44.6 to 95.4% and 85.4-100%, respectively. CONCLUSION: There are many LFAs available with varied sensitivity and specificity. Understanding the diagnostic accuracy of these tests will be vital as we come to rely more on the antibody status of a person moving forward, and as such manufacturer-independent evaluations are crucial.

Pooling sputum for Xpert MTB/RIF and Xpert Ultra testing during the Covid-19 pandemic in Lao People's Democratic Republic.

The global Covid-19 pandemic has limited access to molecular TB diagnostics and National Programmes are struggling to maintain essential services. The pooling method (testing several samples together) could reduce the number of cartridges and staff time needed for TB diagnosis but has not been tested within the pandemic. We conducted two independent cross-sectional surveys. Pools composed of four sputum samples were tested using either Xpert-MTB/RIF or Xpert-Ultra. Pooled and individual results were compared to determine the level of agreement. Each survey included 840 participants and 210 pools. In the Xpert MTB/RIF survey, 77/81 (sensitivity 95.1%, 95%CI 87.8%-98.6%) pools containing ≥1 positive sample tested MTB-positive and 4/81 (4.9%, 95%CI 1.4%-12.2%) tested MTB-negative. All 129/129 pools containing MTB-negative samples tested MTB-negative (specificity 100%, 95%CI 97.2%-100%), with 98.1% agreement (Kappa: 0.959). In the Xpert-Ultra survey, 70/70 (sensitivity 100%, 95%CI 94.9%-100%) pools containing ≥ 1 MTB-positive sample tested MTB-positive and 140/140 (specificity 100%, 95%CI 97.4%-100%) pools containing only MTB-negative samples tested MTB-negative, with 100% agreement (Kappa: 1). Pooled testing with Xpert-MTB/RIF and Xpert-Ultra saved 38.3% and 41.7% (322/840 and 350/840, respectively) in cartridge costs alone. The pooling method with Xpert-MTB/RIF and Xpert-Ultra has similar performance to individual testing and can reduce the number of cartridges needed. These efficiencies can facilitate maintenance of stocks and sustain essential services as countries face difficulties for laboratory procurement during the pandemic and will provide cost and time savings post-pandemic.

Analytical evaluation of thirty-two severe acute respiratory syndrome 2 lateral flow antigen tests demonstrates sensitivity remains with the SARS-CoV-2 Gamma lineage

ABSTRACT Background: The emergence of variants of concern (VOCs) requires an ongoing assessment of the performance of antigen lateral flow tests (Ag-RDTs). The limit of detection (LOD) of 32 Ag-RDTs was evaluated using the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Gamma variant. Methods: Ag-RDTs were performed according to the manufacturer's instructions with a clinical isolate of the Gamma variant. Results: Twenty-eight of the 32 Ag-RDTs exceeded the World Health Organization criteria. Conclusions: This comprehensive analytical evaluation of Ag-RDTs demonstrated that the test performance was maintained with Gamma VOC.

Limit of detection in different matrices of 19 commercially available rapid antigen tests for the detection of SARS-CoV-2.

In the context of the coronavirus disease 2019 (COVID-19) pandemic there has been an increase of the use of antigen-detection rapid diagnostic tests (Ag-RDT). The performance of Ag-RDT vary greatly between manufacturers and evaluating their analytical limit of detection (LOD) has become high priority. Here we describe a manufacturer-independent evaluation of the LOD of 19 marketed Ag-RDT using live SARS-CoV-2 spiked in different matrices: direct culture supernatant, a dry swab, and a swab in Amies. Additionally, the LOD using dry swab was investigated after 7 days' storage at - 80 °C of the SARS-CoV-2 serial dilutions. An LOD of ≈ 5.0 × 102 pfu/ml (1.0 × 106 genome copies/ml) in culture media is defined as acceptable by the World Health Organization. Fourteen of 19 Ag-RDTs (ActiveXpress, Espline, Excalibur, Innova, Joysbio, Mologic, NowCheck, Orient, PanBio, RespiStrip, Roche, Standard-F, Standard-Q and Sure-Status) exceeded this performance criteria using direct culture supernatant applied to the Ag-RDT. Six Ag-RDT were not compatible with Amies media and a decreased sensitivity of 2 to 20-fold was observed for eleven tests on the stored dilutions at - 80 °C for 7 days. Here, we provide analytical sensitivity data to guide appropriate test and sample type selection for use and for future Ag-RDT evaluations.