Project description:Rapid and accurate diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is essential to prevent the spread of the virus. We investigated the diagnostic accuracy of the Xpert Xpress and the ID NOW assays for rapid detection of SARS-CoV-2 using a systemic review and meta-analysis approach. A systematic literature search was performed using PubMed, Embase, and the Cochrane COVID-19 Study Register. The sensitivity and specificity of these tests for detecting viruses in patients with suspected SARS-CoV-2 infection were pooled. We used commercial and laboratory-developed reverse transcription-polymerase chain reactions as reference standards. The Quality Assessment of Diagnostic Accuracy Studies-2 tool was used to assess the risk of bias. We identified 11 studies involving 1734 subjects for the Xpert Xpress assay and 10 studies involving 1778 subjects for the ID NOW assay. The pooled sensitivity and specificity of the Xpert Xpress assay for detection of SARS-CoV-2 were 0.99 (95% confidence interval [CI], 0.97 to 0.99) and 0.97 (95% CI, 0.95 to 0.98), respectively. The pooled sensitivity and specificity of the ID NOW assay were 0.79 (95% CI, 0.69 to 0.86) and 1.00 (95% CI, 0.98 to 1.00), respectively. The studies included in our analysis seemed to have low methodological quality. The Xpert Xpress assay showed excellent diagnostic accuracy for rapid detection of SARS-CoV-2. However, as the ID NOW assay showed relatively low sensitivity, this test might miss several positive samples.
Project description:BACKGROUND:The SARS-CoV-2 pandemic has created an urgent and unprecedented need for rapid large-scale diagnostic testing to inform timely patient management. However, robust data are lacking on the relative performance of available rapid molecular tests across a full range of viral concentrations. OBJECTIVE:This study aimed to compare two recently-authorized rapid tests, Cepheid Xpert Xpress SARS-CoV-2 and Abbott ID Now SARS-CoV-2, to the Roche cobas SARS-CoV-2 assay for samples with low, medium, and high viral concentrations. STUDY DESIGN:A total of 113 nasopharyngeal swabs from remnant patient samples were tested, including 88 positives spanning the full range of observed Ct values on the cobas assay. RESULTS:Compared to cobas, the overall positive agreement was 73.9% with ID Now and 98.9% with Xpert. Negative agreement was 100% and 92.0% for ID Now and Xpert, respectively. Both ID Now and Xpert showed 100% positive agreement for medium and high viral concentrations (Ct value <30). However, for Ct values >30, positive agreement was 34.3% for ID Now and 97.1% for Xpert. CONCLUSIONS:While Xpert showed high agreement with cobas across a wide range of viral concentrations, this study highlights an important limitation of ID Now for specimens collected in viral or universal transport media with low viral concentrations. Further studies are needed to evaluate the performance of ID Now for direct swabs.
Project description:Introduction. The ID NOW is FDA approved for the detection of SARS-CoV-2 in symptomatic individuals within the first 7 days of symptom onset for COVID-19 if tested within 1 h of specimen collection.Gap statement. Clinical data on the performance of the ID NOW are limited, with many studies varying in their study design and/or having small sample size.Aim. In this study we aimed to determine the clinical performance of the ID NOW compared to conventional RT-PCR testing.Methodology. Adults with COVID-19 in the community or hospital were recruited into the study. Paired throat swabs were collected, with one throat swab transported immediately in an empty sterile tube to the laboratory for ID NOW testing, and the other transported in universal transport media and tested by an in-house SARS-CoV-2 RT-PCR assay targeting the E gene.Results. In total, 133 individuals were included in the study; 129 samples were positive on either the ID NOW and/or RT-PCR. Assuming any positive result on either assay represents a true positive, positive per cent agreement (PPA) of the ID NOW compared to RT-PCR with 95 % confidence intervals was 89.1 % (82.0-94.1%) and 91.6 % (85.1-95.9%), respectively. When analysing individuals with symptom duration ≤7 days and who had the ID NOW performed within 1 h (n=62), ID NOW PPA increased to 98.2 %.Conclusion. Results from the ID NOW were reliable, especially when adhering to the manufacturer's recommendations for testing.
Project description:BACKGROUND:The SARS-CoV-2 pandemic caused a major surge in needed diagnostic capacity. In response, many EUA assays have become available for clinical laboratories, and more recently, the point of care device, Abbott ID NOW. OBJECTIVES:To determine the analytical performance of the ID NOW assay for detecting SARS-CoV-2. STUDY DESIGN:Residual NP samples collected in viral transport media were tested by the ID NOW platform in two independent laboratories. Results were compared to either the CDC or New York EUA assays, which served as reference methods. RESULTS:Overall agreement of ID NOW was 78.7%. Sensitivity was 71.7% and specificity was 100%. Notably, all false-negative results correlated to those samples that were weakly positive. CONCLUSIONS:ID NOW performs well for strong and moderately positive samples but has reduced sensitivity for weakly positive samples. This sensitivity, among other concerns, should be taken into consideration when using this test for patients with a low suspicion for COVID-19 disease.
Project description:The Abbott ID Now COVID-19 assay is a point-of-care molecular diagnostic tool for the detection of SARS-CoV-2. We prospectively monitored implementation of the assay in a tertiary care hospital emergency department (ED) for the diagnosis of early symptomatic patients. A total of 269 paired nasopharyngeal swabs were tested in parallel with the ID Now and laboratory-based molecular methodologies, 191 of which met selection criteria for testing based on symptoms description and duration. Forty-six and 48 samples were positive for SARS-CoV-2 with the ID Now and reference molecular assays respectively. Percent positive and negative agreement were high (93.8% and 99.6% respectively), as were the sensitivity and specificity (93.8% and 99.5%). ID Now results were available 17.47 hours earlier than qRT-PCR. In symptomatic patients seen in ED within 7 to 10 days of symptoms onset, the ID Now COVID-19 assay allows for rapid and accurate detection of infection.
Project description:PurposeHealthcare workers have experienced high levels of anxiety during the COVID-19 pandemic, particularly when caring for patients with unknown infection status. We trialled rapid preoperative point-of-care COVID-19 testing using the Abbott ID NOW™ COVID-19 for clinical validation in an urgent surgical population at a single centre in British Columbia, Canada. Here, we sought to determine the opinions and beliefs of operating room (OR) staff on the usefulness and effectiveness of point-of-care tests on workflow and wellbeing in the OR.MethodsThis descriptive study used a mixed-methods cross-sectional survey of all OR staff (nurses, anesthesiologists, surgeons, and ancillary staff) at a single centre after using the ID NOW for three months. Outcomes of interest included healthcare worker satisfaction with the ID NOW, effects on OR workflow, and worries about COVID-19 transmission.ResultsThe overall response rate was 56% (n = 133), and was highest among anesthesiologists (100%, n = 38). Respondents were satisfied with the performance of the ID NOW for rapid COVID-19 testing in preoperative patients, giving it a mean (standard deviation [SD]) rate of 4.4 [1.4] on a five-point scale. Most (115/128, 90%) recommended continued use of the ID NOW on asymptomatic patients while there are active cases of COVID-19 in the community. Respondents felt that preoperative COVID-19 testing with the ID NOW made the OR safer for staff (mean [SD] rate, 4.2 [0.8]) and patients (mean [SD] rate, 4.0 [0.9]).ConclusionDuring the COVID-19 pandemic, it is important to maintain the physical and mental wellbeing of hospital staff. Rapid point-of-care testing increased the sense of workplace safety, improved morale, and reduced worry associated with COVID-19 without excessive disruption of OR workflow.
Project description:Rapid, inexpensive, robust diagnostics are essential to control the spread of infectious diseases. Current state of the art diagnostics are highly sensitive and specific, but slow, and require expensive equipment. Here we report the development of a molecular diagnostic test for SARS-CoV-2 based on an enhanced recombinase polymerase amplification (eRPA) reaction. eRPA has a detection limit on patient samples down to 5 viral copies, requires minimal instrumentation, and is highly scalable and inexpensive. eRPA does not cross-react with other common coronaviruses, does not require RNA purification, and takes ~45 min from sample collection to results. eRPA represents a first step toward at-home SARS-CoV-2 detection and can be adapted to future viruses within days of genomic sequence availability.
Project description:Recently, RNA viral infections caused by respiratory viruses, such as influenza, parainfluenza, respiratory syncytial virus, coronavirus, and Middle East respiratory syndrome-coronavirus (MERS-CoV), and Zika virus, are a major public health threats in the world. Although myriads of diagnostic methods based on RNA amplification have been developed in the last decades, they continue to lack speed, sensitivity, and specificity for clinical use. A rapid and accurate diagnostic method is needed for appropriate control, including isolation and treatment of the patients. Here, we report an isothermal, label-free, one-step RNA amplification and detection system, termed as iROAD, for the diagnosis of respiratory diseases. It couples a one-step isothermal RNA amplification method and a bio-optical sensor for simultaneous viral RNA amplification/detection in a label-free and real-time manner. The iROAD assay offers a one-step viral RNA amplification/detection example to rapid analysis (<20min). The detection limit of iROAD assay was found to be 10-times more sensitive than that of real-time reverse transcription-PCR method. We confirmed the clinical utility of the iROAD assay by detecting viral RNAs obtained from 63 human respiratory samples. We envision that the iROAD assay will be useful and potentially adaptable for better diagnosis of emerging infectious diseases including respiratory diseases.
Project description:BackgroundSensitive assays are needed for detection of residual human immunodeficiency virus (HIV) in patients with undetectable plasma viral loads to determine whether eradication strategies are effective. The gold standard quantitative viral outgrowth assay (QVOA) underestimates the magnitude of the viral reservoir. We sought to determine whether xenograft of leukocytes from HIV type 1 (HIV)-infected patients with undetectable plasma viral loads into immunocompromised mice would result in viral amplification.MethodsPeripheral blood mononuclear cells or purified CD4(+) T cells from HIV or simian immunodeficiency virus (SIV)-infected subjects with undetectable plasma viral loads were adoptively transferred into NOD.Cg-Prkdc(scid)Il2rg(tm1Wjl)/SzJ (NSG) mice. The mice were monitored for viremia following depletion of human CD8(+) T cells to minimize antiviral activity. In some cases, humanized mice were also treated with activating anti-CD3 antibody.ResultsWith this murine viral outgrowth assay (MVOA), we successfully amplified replication-competent HIV or SIV from all subjects tested, including 5 HIV-positive patients receiving suppressive antiretroviral therapy (ART) and 6 elite controllers or suppressors who were maintaining undetectable viral loads without ART, including an elite suppressor from whom we were unable to recover virus by QVOA.ConclusionsOur results suggest that the MVOA has the potential to serve as a powerful tool to identify residual HIV in patients with undetectable viral loads.
Project description:Emerging evidences have shown the utility of saliva for the detection of SARS-CoV-2 by PCR as alternative to nasopharyngeal swab (NPS). However, conflicting results have been reported regarding viral loads between NPS and saliva. We conducted a study to compare the viral loads between NPS and saliva in 42 COVID-19 patients. Viral loads were estimated by the cycle threshold (Ct) values. SARS-CoV-2 was detected in 34 (81%) using NPS with median Ct value of 27.4, and 38 (90%) using saliva with median Ct value of 28.9 (P = 0.79). Kendall's W was 0.82, showing a high degree of agreement, indicating equivalent viral loads in NPS and saliva. After symptom onset, the Ct values of both NPS and saliva continued to increase over time, with no substantial difference. Self-collected saliva has a detection sensitivity comparable to that of NPS and is a useful diagnostic tool with mitigating uncomfortable process and the risk of aerosol transmission to healthcare workers.