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1.
PLoS One ; 16(3): e0248921, 2021.
Artículo en Inglés | MEDLINE | ID: covidwho-1173655

RESUMEN

OBJECTIVES: Determine the diagnostic accuracy of two antigen-detecting rapid diagnostic tests (Ag-RDT) for SARS-CoV-2 at the point of care and define individuals' characteristics providing best performance. METHODS: We performed a prospective, single-center, point of care validation of two Ag-RDT in comparison to RT-PCR on nasopharyngeal swabs. RESULTS: Between October 9th and 23rd, 2020, 1064 participants were enrolled. The PanbioTM Covid-19 Ag Rapid Test device (Abbott) was validated in 535 participants, with 106 positive Ag-RDT results out of 124 positive RT-PCR individuals, yielding a sensitivity of 85.5% (95% CI: 78.0-91.2). Specificity was 100.0% (95% CI: 99.1-100) in 411 RT-PCR negative individuals. The Standard Q Ag-RDT (SD Biosensor, Roche) was validated in 529 participants, with 170 positive Ag-RDT results out of 191 positive RT-PCR individuals, yielding a sensitivity of 89.0% (95%CI: 83.7-93.1). One false positive result was obtained in 338 RT-PCR negative individuals, yielding a specificity of 99.7% (95%CI: 98.4-100). For individuals presenting with fever 1-5 days post symptom onset, combined Ag-RDT sensitivity was above 95%. Lower sensitivity of 88.2% was seen on the same day of symptom development (day 0). CONCLUSIONS: We provide an independent validation of two widely available commercial Ag-RDTs, both meeting WHO criteria of ≥80% sensitivity and ≥97% specificity. Although less sensitive than RT-PCR, these assays could be beneficial due to their rapid results, ease of use, and independence from existing laboratory structures. Testing criteria focusing on patients with typical symptoms in their early symptomatic period onset could further increase diagnostic value.


Asunto(s)
Antígenos Virales/análisis , Sistemas de Atención de Punto , Características de la Residencia , /aislamiento & purificación , Adulto , Femenino , Humanos , Masculino , Sensibilidad y Especificidad , Factores de Tiempo , Carga Viral
2.
Nat Commun ; 12(1): 1951, 2021 03 29.
Artículo en Inglés | MEDLINE | ID: covidwho-1157905

RESUMEN

Serological detection of antibodies to SARS-CoV-2 is essential for establishing rates of seroconversion in populations, and for seeking evidence for a level of antibody that may be protective against COVID-19 disease. Several high-performance commercial tests have been described, but these require centralised laboratory facilities that are comparatively expensive, and therefore not available universally. Red cell agglutination tests do not require special equipment, are read by eye, have short development times, low cost and can be applied at the Point of Care. Here we describe a quantitative Haemagglutination test (HAT) for the detection of antibodies to the receptor binding domain of the SARS-CoV-2 spike protein. The HAT has a sensitivity of 90% and specificity of 99% for detection of antibodies after a PCR diagnosed infection. We will supply aliquots of the test reagent sufficient for ten thousand test wells free of charge to qualified research groups anywhere in the world.


Asunto(s)
Anticuerpos Antivirales/análisis , /diagnóstico , Pruebas de Hemaglutinación/métodos , Glicoproteína de la Espiga del Coronavirus/inmunología , Pruebas de Aglutinación/métodos , Anticuerpos Monoclonales/inmunología , Anticuerpos Antivirales/sangre , Anticuerpos Antivirales/inmunología , /inmunología , Ensayo de Inmunoadsorción Enzimática/métodos , Humanos , Sistemas de Atención de Punto , Reacción en Cadena de la Polimerasa , Sensibilidad y Especificidad , Seroconversión
3.
Nat Commun ; 12(1): 1931, 2021 03 26.
Artículo en Inglés | MEDLINE | ID: covidwho-1152851

RESUMEN

The COVID-19 pandemic continues to have an unprecedented impact on societies and economies worldwide. There remains an ongoing need for high-performance SARS-CoV-2 tests which may be broadly deployed for infection monitoring. Here we report a highly sensitive single molecule array (Simoa) immunoassay in development for detection of SARS-CoV-2 nucleocapsid protein (N-protein) in venous and capillary blood and saliva. In all matrices in the studies conducted to date we observe >98% negative percent agreement and >90% positive percent agreement with molecular testing for days 1-7 in symptomatic, asymptomatic, and pre-symptomatic PCR+ individuals. N-protein load decreases as anti-SARS-CoV-2 spike-IgG increases, and N-protein levels correlate with RT-PCR Ct-values in saliva, and between matched saliva and capillary blood samples. This Simoa SARS-CoV-2 N-protein assay effectively detects SARS-CoV-2 infection via measurement of antigen levels in blood or saliva, using non-invasive, swab-independent collection methods, offering potential for at home and point of care sample collection.


Asunto(s)
/métodos , /sangre , Saliva/virología , /epidemiología , /genética , Epidemias , Servicios de Atención de Salud a Domicilio , Humanos , Sistemas de Atención de Punto , Curva ROC , /fisiología , Manejo de Especímenes/métodos
4.
Cochrane Database Syst Rev ; 3: CD013705, 2021 03 24.
Artículo en Inglés | MEDLINE | ID: covidwho-1147548

RESUMEN

BACKGROUND: Accurate rapid diagnostic tests for SARS-CoV-2 infection could contribute to clinical and public health strategies to manage the COVID-19 pandemic. Point-of-care antigen and molecular tests to detect current infection could increase access to testing and early confirmation of cases, and expediate clinical and public health management decisions that may reduce transmission. OBJECTIVES: To assess the diagnostic accuracy of point-of-care antigen and molecular-based tests for diagnosis of SARS-CoV-2 infection. We consider accuracy separately in symptomatic and asymptomatic population groups. SEARCH METHODS: Electronic searches of the Cochrane COVID-19 Study Register and the COVID-19 Living Evidence Database from the University of Bern (which includes daily updates from PubMed and Embase and preprints from medRxiv and bioRxiv) were undertaken on 30 Sept 2020. We checked repositories of COVID-19 publications and included independent evaluations from national reference laboratories, the Foundation for Innovative New Diagnostics and the Diagnostics Global Health website to 16 Nov 2020. We did not apply language restrictions. SELECTION CRITERIA: We included studies of people with either suspected SARS-CoV-2 infection, known SARS-CoV-2 infection or known absence of infection, or those who were being screened for infection. We included test accuracy studies of any design that evaluated commercially produced, rapid antigen or molecular tests suitable for a point-of-care setting (minimal equipment, sample preparation, and biosafety requirements, with results within two hours of sample collection). We included all reference standards that define the presence or absence of SARS-CoV-2 (including reverse transcription polymerase chain reaction (RT-PCR) tests and established diagnostic criteria). DATA COLLECTION AND ANALYSIS: Studies were screened independently in duplicate with disagreements resolved by discussion with a third author. Study characteristics were extracted by one author and checked by a second; extraction of study results and assessments of risk of bias and applicability (made using the QUADAS-2 tool) were undertaken independently in duplicate. We present sensitivity and specificity with 95% confidence intervals (CIs) for each test and pooled data using the bivariate model separately for antigen and molecular-based tests. We tabulated results by test manufacturer and compliance with manufacturer instructions for use and according to symptom status. MAIN RESULTS: Seventy-eight study cohorts were included (described in 64 study reports, including 20 pre-prints), reporting results for 24,087 samples (7,415 with confirmed SARS-CoV-2). Studies were mainly from Europe (n = 39) or North America (n = 20), and evaluated 16 antigen and five molecular assays. We considered risk of bias to be high in 29 (50%) studies because of participant selection; in 66 (85%) because of weaknesses in the reference standard for absence of infection; and in 29 (45%) for participant flow and timing. Studies of antigen tests were of a higher methodological quality compared to studies of molecular tests, particularly regarding the risk of bias for participant selection and the index test. Characteristics of participants in 35 (45%) studies differed from those in whom the test was intended to be used and the delivery of the index test in 39 (50%) studies differed from the way in which the test was intended to be used. Nearly all studies (97%) defined the presence or absence of SARS-CoV-2 based on a single RT-PCR result, and none included participants meeting case definitions for probable COVID-19. Antigen tests Forty-eight studies reported 58 evaluations of antigen tests. Estimates of sensitivity varied considerably between studies. There were differences between symptomatic (72.0%, 95% CI 63.7% to 79.0%; 37 evaluations; 15530 samples, 4410 cases) and asymptomatic participants (58.1%, 95% CI 40.2% to 74.1%; 12 evaluations; 1581 samples, 295 cases). Average sensitivity was higher in the first week after symptom onset (78.3%, 95% CI 71.1% to 84.1%; 26 evaluations; 5769 samples, 2320 cases) than in the second week of symptoms (51.0%, 95% CI 40.8% to 61.0%; 22 evaluations; 935 samples, 692 cases). Sensitivity was high in those with cycle threshold (Ct) values on PCR ≤25 (94.5%, 95% CI 91.0% to 96.7%; 36 evaluations; 2613 cases) compared to those with Ct values >25 (40.7%, 95% CI 31.8% to 50.3%; 36 evaluations; 2632 cases). Sensitivity varied between brands. Using data from instructions for use (IFU) compliant evaluations in symptomatic participants, summary sensitivities ranged from 34.1% (95% CI 29.7% to 38.8%; Coris Bioconcept) to 88.1% (95% CI 84.2% to 91.1%; SD Biosensor STANDARD Q). Average specificities were high in symptomatic and asymptomatic participants, and for most brands (overall summary specificity 99.6%, 95% CI 99.0% to 99.8%). At 5% prevalence using data for the most sensitive assays in symptomatic people (SD Biosensor STANDARD Q and Abbott Panbio), positive predictive values (PPVs) of 84% to 90% mean that between 1 in 10 and 1 in 6 positive results will be a false positive, and between 1 in 4 and 1 in 8 cases will be missed. At 0.5% prevalence applying the same tests in asymptomatic people would result in PPVs of 11% to 28% meaning that between 7 in 10 and 9 in 10 positive results will be false positives, and between 1 in 2 and 1 in 3 cases will be missed. No studies assessed the accuracy of repeated lateral flow testing or self-testing. Rapid molecular assays Thirty studies reported 33 evaluations of five different rapid molecular tests. Sensitivities varied according to test brand. Most of the data relate to the ID NOW and Xpert Xpress assays. Using data from evaluations following the manufacturer's instructions for use, the average sensitivity of ID NOW was 73.0% (95% CI 66.8% to 78.4%) and average specificity 99.7% (95% CI 98.7% to 99.9%; 4 evaluations; 812 samples, 222 cases). For Xpert Xpress, the average sensitivity was 100% (95% CI 88.1% to 100%) and average specificity 97.2% (95% CI 89.4% to 99.3%; 2 evaluations; 100 samples, 29 cases). Insufficient data were available to investigate the effect of symptom status or time after symptom onset. AUTHORS' CONCLUSIONS: Antigen tests vary in sensitivity. In people with signs and symptoms of COVID-19, sensitivities are highest in the first week of illness when viral loads are higher. The assays shown to meet appropriate criteria, such as WHO's priority target product profiles for COVID-19 diagnostics ('acceptable' sensitivity ≥ 80% and specificity ≥ 97%), can be considered as a replacement for laboratory-based RT-PCR when immediate decisions about patient care must be made, or where RT-PCR cannot be delivered in a timely manner. Positive predictive values suggest that confirmatory testing of those with positive results may be considered in low prevalence settings. Due to the variable sensitivity of antigen tests, people who test negative may still be infected. Evidence for testing in asymptomatic cohorts was limited. Test accuracy studies cannot adequately assess the ability of antigen tests to differentiate those who are infectious and require isolation from those who pose no risk, as there is no reference standard for infectiousness. A small number of molecular tests showed high accuracy and may be suitable alternatives to RT-PCR. However, further evaluations of the tests in settings as they are intended to be used are required to fully establish performance in practice. Several important studies in asymptomatic individuals have been reported since the close of our search and will be incorporated at the next update of this review. Comparative studies of antigen tests in their intended use settings and according to test operator (including self-testing) are required.


Asunto(s)
Antígenos Virales/análisis , /diagnóstico , Técnicas de Diagnóstico Molecular/métodos , Sistemas de Atención de Punto , /inmunología , Adulto , Infecciones Asintomáticas , Sesgo , Niño , Estudios de Cohortes , Reacciones Falso Negativas , Reacciones Falso Positivas , Humanos , Técnicas de Diagnóstico Molecular/normas , Valor Predictivo de las Pruebas , Estándares de Referencia , Sensibilidad y Especificidad
5.
BMC Med Educ ; 21(1): 175, 2021 Mar 20.
Artículo en Inglés | MEDLINE | ID: covidwho-1143211

RESUMEN

BACKGROUND: Point-of-care ultrasound is becoming a ubiquitous diagnostic tool, and there has been increasing interest to teach novice practitioners. One of the challenges is the scarcity of qualified instructors, and with COVID-19, another challenge is the difficulty with social distancing between learners and educators. The purpose of our study was to determine if ultrasound-naïve operators can learn ultrasound techniques and develop the psychomotor skills to acquire ultrasound images after reviewing SonoSim® online modules. METHODS: This was a prospective study evaluating first-year medical students. Medical students were asked to complete four SonoSim® online modules (aorta/IVC, cardiac, renal, and superficial). They were subsequently asked to perform ultrasound examinations on standardized patients utilizing the learned techniques/skills in the online modules. Emergency Ultrasound-trained physicians evaluated medical students' sonographic skills in image acquisition quality, image acquisition difficulty, and overall performance. Data are presented as means and percentages with standard deviation. All P values are based on 2-tailed tests of significance. RESULTS: Total of 44 medical students participated in the study. All (100%) students completed the hands-on skills evaluation with a median score of 83.7% (IQR 76.7-88.4%). Thirty-three medical students completed all the online modules and quizzes with median score of 87.5% (IQR 83.8-91.3%). There was a positive association between module quiz performance and the hands-on skills performance (R-squared = 0.45; p < 0.001). There was no statistically significant association between module performance and hands-on performance for any of the four categories individually. In all four categories, the evaluators' observation of the medical students' difficulty obtaining views correlated with hands-on performance scores. CONCLUSIONS: Our study findings suggest that ultrasound-naïve medical students can develop basic hands-on skills in image acquisition after reviewing online modules.


Asunto(s)
Competencia Clínica , Educación a Distancia/métodos , Educación de Pregrado en Medicina/métodos , Sistemas de Atención de Punto , Ultrasonografía , /epidemiología , Femenino , Humanos , Masculino , Estudios Prospectivos
6.
Indian J Ophthalmol ; 69(4): 964-970, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: covidwho-1138818

RESUMEN

Purpose: The aim of this study was to report the use and the impact of a point-of-care rapid antigen test (PoC-RAT) at a tertiary eye care facility in facilitating commencement of elective surgeries, contact tracing of exposed health care professionals (HCPs) and ancillary hospital staff, and implementation of back-to-work (BTW) policy for them. Methods: Retrospective analysis of subjects undergoing PoC-RAT for COVID-19 infection at a tertiary level dedicated eye care facility. Decision making with regard to commencement of elective surgeries post COVID-19 related discontinuation of services, contact tracing of HCPs and ancillary hospital staff exposed to known COVID-19 cases and implementation of back-to-work policy for all staff based upon the results of PoC-RAT were studied. Results: A total of 311 subjects (224 patients and 87 hospital staff) were tested. Overall positivity rate was around 7%. Asymptomatic patients who were screened preoperatively had a lower positivity rate at around 3% compared to the staff (who were either known contacts or were symptomatic) at around 17%. Contact tracing found three-quarters of the staff at low risk and only one quarter at medium or high risk. Among patients, 97% of those followed up for at least 2 weeks after the test remained healthy. For staff, this was around 65%. Conclusion: Based on our preliminary results, we suggest that PoC-RAT may be considered routinely for indication-based preoperative screening of asymptomatic patients, and for on-campus screening, contact tracing and implementation of BTW policies for HCPs and ancillary hospital staff at a tertiary level eye care facility.


Asunto(s)
Antígenos Virales/inmunología , /diagnóstico , Trazado de Contacto , Procedimientos Quirúrgicos Electivos , Reinserción al Trabajo , /inmunología , Adulto , Toma de Decisiones , Femenino , Política de Salud , Humanos , India/epidemiología , Masculino , Persona de Mediana Edad , Sistemas de Atención de Punto , Cuidados Preoperatorios , Estudios Retrospectivos , Centros de Atención Terciaria
7.
BMJ Case Rep ; 14(3)2021 Mar 16.
Artículo en Inglés | MEDLINE | ID: covidwho-1138314

RESUMEN

A 64-year-old man was intubated and ventilated for COVID-19-associated acute respiratory distress syndrome. He had a background history of chronic obstructive pulmonary disease and ischaemic heart disease. His oxygen saturations dropped rapidly to 80% on day 9 of ICU admission. Chest auscultation revealed absent breath sounds over the left upper chest which raised suspicions for pneumothorax, of which a small stable left apical pneumothorax was documented on a recent CT scan of the thorax. Point-of-care ultrasonography was performed prior to attempting chest drain insertion which demonstrated sliding pleura on the left side (GE Healthcare model: Vscan Extend-display: 5 inches, 720×1280 pixels resolution, sector probe-broad bandwidth: 1.7-3.8 MHz, 24 cm penetration and linear probe-broad bandwidth: 3.3-8 MHz, 8 cm penetration). A portable chest X-ray was obtained which demonstrated left upper lobe collapse secondary to mucus plugging. The mucus plug was successfully suctioned from the patient's airway using bedside bronchoscopy subsequently improving the patient's oxygen saturation. A follow-up chest X-ray and CT scan of the thorax demonstrated interval resolution of the left upper lobe collapse. While expansion of his existing pneumothorax was first on the list of differential diagnoses, the use of ultrasonography early in the patient's assessment ensured it was ruled out prior to attempting chest drain insertion, thus prompting the acquisition of the chest X-ray which subsequently demonstrated the left upper lobe collapse as the correct diagnosis.


Asunto(s)
/complicaciones , Cuidados Críticos/métodos , Sistemas de Atención de Punto , /etiología , Ultrasonografía/métodos , /sangre , Diagnóstico Diferencial , Humanos , Pulmón/diagnóstico por imagen , Masculino , Persona de Mediana Edad , Oxígeno/sangre , /sangre
8.
PLoS One ; 16(3): e0248729, 2021.
Artículo en Inglés | MEDLINE | ID: covidwho-1136300

RESUMEN

BACKGROUND: As COVID-19 vaccines become available, screening individuals for prior COVID-19 infection and vaccine response in point-of-care (POC) settings has renewed interest. We prospectively screened at-risk individuals for SARS-CoV-2 spike and nucleocapsid protein antibodies in a POC setting to determine if it was a feasible method to identify antibody from prior infection. METHODS: Three EUA-approved lateral flow antibody assays were performed on POC finger-stick blood and compared with serum and a CLIA nucleocapsid antibody immunoassay. Variables including antibody class, time since PCR, and the assay antigen used were evaluated. RESULTS: 512 subjects enrolled, of which 104 had a COVID-19 history and positive PCR. Only three PCR-positive subjects required hospitalization, with one requiring mechanical ventilation. The POC results correlated well with the immunoassay (93-97% sensitivity) and using serum did not improve the sensitivity or specificity. CONCLUSIONS: Finger-stick, POC COVID-19 antibody testing was highly effective in identifying antibody resulting from prior infections in mildly symptomatic subjects. Using high-complexity serum immunoassays did not improve the screening outcome. Almost all individuals with COVID-19 infection produced detectable antibodies to the virus. POC antibody testing is useful as a screen for prior COVID-19 infection, and should be useful in assessing vaccine response.


Asunto(s)
/diagnóstico , Sistemas de Atención de Punto , Adulto , Anciano , Anticuerpos Antivirales/sangre , Femenino , Humanos , Inmunoensayo , Inmunoglobulina G/sangre , Inmunoglobulina M/sangre , Masculino , Persona de Mediana Edad , Nucleocápside/inmunología , Juego de Reactivos para Diagnóstico , /aislamiento & purificación , Sensibilidad y Especificidad , Adulto Joven
9.
Ann Am Thorac Soc ; 17(7): 879-891, 2020 07.
Artículo en Inglés | MEDLINE | ID: covidwho-679536

RESUMEN

There is broad interest in improved methods to generate robust evidence regarding best practice, especially in settings where patient conditions are heterogenous and require multiple concomitant therapies. Here, we present the rationale and design of a large, international trial that combines features of adaptive platform trials with pragmatic point-of-care trials to determine best treatment strategies for patients admitted to an intensive care unit with severe community-acquired pneumonia. The trial uses a novel design, entitled "a randomized embedded multifactorial adaptive platform." The design has five key features: 1) randomization, allowing robust causal inference; 2) embedding of study procedures into routine care processes, facilitating enrollment, trial efficiency, and generalizability; 3) a multifactorial statistical model comparing multiple interventions across multiple patient subgroups; 4) response-adaptive randomization with preferential assignment to those interventions that appear most favorable; and 5) a platform structured to permit continuous, potentially perpetual enrollment beyond the evaluation of the initial treatments. The trial randomizes patients to multiple interventions within four treatment domains: antibiotics, antiviral therapy for influenza, host immunomodulation with extended macrolide therapy, and alternative corticosteroid regimens, representing 240 treatment regimens. The trial generates estimates of superiority, inferiority, and equivalence between regimens on the primary outcome of 90-day mortality, stratified by presence or absence of concomitant shock and proven or suspected influenza infection. The trial will also compare ventilatory and oxygenation strategies, and has capacity to address additional questions rapidly during pandemic respiratory infections. As of January 2020, REMAP-CAP (Randomized Embedded Multifactorial Adaptive Platform for Community-acquired Pneumonia) was approved and enrolling patients in 52 intensive care units in 13 countries on 3 continents. In February, it transitioned into pandemic mode with several design adaptations for coronavirus disease 2019. Lessons learned from the design and conduct of this trial should aid in dissemination of similar platform initiatives in other disease areas.Clinical trial registered with www.clinicaltrials.gov (NCT02735707).


Asunto(s)
Infecciones Comunitarias Adquiridas/terapia , Infecciones por Coronavirus/terapia , Gripe Humana/terapia , Neumonía Viral/terapia , Neumonía/terapia , Antibacterianos/uso terapéutico , Antivirales/uso terapéutico , Betacoronavirus , Medicina Basada en la Evidencia , Humanos , Pandemias , Sistemas de Atención de Punto
10.
J Infect Dev Ctries ; 15(2): 237-241, 2021 03 07.
Artículo en Inglés | MEDLINE | ID: covidwho-1125228

RESUMEN

INTRODUCTION: We aim to describe the performance of combined IgM and IgG point-of-care antibody test (POC-Ab) (Wondfo®) compared to real-time reverse transcriptase (rRT-PCR) (Allplex™ 2019-nCoV Assay) in detecting coronavirus disease 2019 (COVID-19). METHODOLOGY: We compared POC-Ab with rRT-PCR results among patients in a tertiary hospital from January to March 2020 in Bandung, Indonesia. We selected presumptive COVID-19 patients with positive rRT-PCR consecutively and 20 patients with negative rRT-PCR results were selected randomly from the same group of patients as controls. We described the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) with corresponding 95% confidence interval using serum and capillary blood samples. We also tested POC-Ab using non-COVID-19 (confirmed dengue and typhoid) patients' sera. RESULTS: Twenty-seven patients with positive rRT-PCR result and 20 negative controls were included (68.1% males, mean age 46 (SD: 15.4)). Using the serum, the sensitivity of the POC-Ab was 63.0% (42.4-80.6), specificity was 95.0% (75.1-99.9), PPV was 94.4% (72.7-99.8), NPV was 65.5% (45.7-82.1). A subset of 20 patients was tested using a capillary blood sample. The accuracy of the capillary blood sample is lower compared to serum (50.0% vs. 78.7%). None of the non-COVID-19 sera tested were reactive. CONCLUSIONS: POC-Ab for COVID-19 has a high specificity with no false-positive result in non-COVID-19 sera. Therefore, it can be used to guide diagnostic among symptomatic patients in resource limited settings. Given its low sensitivity, patients with high suspicion of COVID-19 but non-reactive result should be prioritized for rRT-PCR testing.


Asunto(s)
/métodos , Adulto , Anciano , /etiología , Reacciones Falso Positivas , Femenino , Humanos , Inmunoglobulina G/sangre , Inmunoglobulina M/sangre , Indonesia , Masculino , Persona de Mediana Edad , Nasofaringe/virología , Sistemas de Atención de Punto , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , Sensibilidad y Especificidad , Centros de Atención Terciaria
12.
Anal Chem ; 93(9): 4154-4159, 2021 03 09.
Artículo en Inglés | MEDLINE | ID: covidwho-1108879

RESUMEN

Chip-scale SARS-CoV-2 testing was demonstrated using silicon nitride (Si3N4) nanoslot fluidic waveguides to detect a tagged oligonucleotide with a coronavirus DNA sequence. The slot waveguides were fabricated using complementary metal-oxide-semiconductor (CMOS) fabrication processes, including multiscale lithography and selective reactive ion etching (RIE), forming femtoliter fluidic channels. Finite difference method (FDM) simulation was used to calculate the optical field distribution of the waveguide mode when the waveguide sensor was excited by transverse electric (TE) and transverse magnetic (TM) polarized light. For the TE polarization, a strong optical field was created in the slot region and its field intensity was 14× stronger than the evanescent sensing field from the TM polarization. The nanoscale confinement of the optical sensing field significantly enhanced the light-analyte interaction and improved the optical sensitivity. The sensitivity enhancement was experimentally demonstrated by measuring the polarization-dependent fluorescence emission from the tagged oligonucleotide. The photonic chips consisting of femtoliter Si3N4 waveguides provide a low-cost and high throughput platform for real-time virus identification, which is critical for point-of-care (PoC) diagnostic applications.


Asunto(s)
/métodos , /virología , ADN Viral/análisis , Nanopartículas/química , /aislamiento & purificación , Compuestos de Silicona/química , Humanos , Óptica y Fotónica , Sistemas de Atención de Punto , Refractometría , Semiconductores , Sensibilidad y Especificidad
13.
ASAIO J ; 67(3): 254-262, 2021 03 01.
Artículo en Inglés | MEDLINE | ID: covidwho-1101913

RESUMEN

Viscoelastic coagulation monitor (VCM) is a portable device developed to evaluate the viscoelastic properties of whole blood activated by contact with glass. In this study, VCM was employed to analyze the viscoelastic profiles of 36 COVID-19 intensive care patients. Full anticoagulant dose heparin (unfractionated [UFH]; low molecular weight [LMWH]) was administrated to all patients. The association between VCM and laboratory parameters was retrospectively analyzed. The administration of UFH-influenced VCM parameters prolonging clotting time (CT) and clot formation time (CFT) and reducing angle (alpha) and amplitudes of the VCM tracings (A10, A20, and maximum clot firmness [MCF]) compared with LMWH therapy. A tendency toward hypercoagulation was observed by short CT and CFT in patients receiving LMWH. Clotting time was correlated with UFH dose (Spearman's rho = 0.48, p ≤ 0.001), and no correlation was found between CT and LMWH. All VCM tracings failed to show lysis at 30 and 45 minutes, indicating the absence of fibrinolysis. A10, A20, and MCF exhibited very-good to good diagnostic accuracy for detecting platelet count and fibrinogen above the upper reference limit of the laboratory. In conclusion, VCM provided reliable results in COVID-19 patients and was easy to perform with minimal training at the bedside.


Asunto(s)
/sangre , Monitoreo Fisiológico/instrumentación , Sistemas de Atención de Punto , Tromboelastografía/instrumentación , Adulto , Coagulación Sanguínea , Femenino , Humanos , Masculino , Persona de Mediana Edad , Monitoreo Fisiológico/métodos , Estudios Retrospectivos , Tromboelastografía/métodos , Trombosis/diagnóstico , Trombosis/virología
14.
Clin Lab ; 67(2)2021 Feb 01.
Artículo en Inglés | MEDLINE | ID: covidwho-1094346

RESUMEN

BACKGROUND: COVID-19 has recently been declared an epidemic by the WHO, and there is an urgent need for affected countries and laboratories to assess and treat people at risk of COVID-19. A heat procedure has been suggested for specimen inactivation. This study was designed to evaluate the effect of serum heating on biochemical indexes, and providing a basis for accurate detection results of the COVID-19 patients. METHODS: We collected 29 normal cases of two tubes of 5 mL whole blood. One tube was analyzed directly, and the other was analyzed after heating at 56°C 30 minutes. RESULTS: A total of 34 serum biochemical index quantitative results were obtained, 28/34 indexes were not significantly affected by the heat inactivation and remained clinically interpretable. As the thermal inactivation for these indexes showed good correlation, ALB (p = 0.04, Pearson R = 0.91, 2.6% mean increase), CysC (p = 0.03, Pearson R = 0.98, 9.9% mean increase), CO2CP (p < 0.001, Pearson R = 0.96, 13% mean decrease), they were still inter-pretable. Four biochemical indexes ALP, CK, CK-MB, and insulin were inactivated and showed significant statistical differences (p < 0.001). CONCLUSIONS: Our study showed CK, CK-MB, ALP, and insulin were sensitive to heat and will be inhibited or degrade after heating, indicating that the rapid decrease of this indexes in the COVID-19 patients may be caused by sample heat inactivation. For safety and diagnostic accuracy, we recommend the use of a point-of-care device for blood gases, electrolytes, troponin, and liver and renal function tests within a ISL 2 or above biosafety cabinet with level 3 or above biosafety laboratory practice.


Asunto(s)
Análisis Químico de la Sangre , Errores Diagnósticos/prevención & control , Calor/efectos adversos , Inactivación de Virus , Fosfatasa Alcalina/sangre , Análisis Químico de la Sangre/métodos , Análisis Químico de la Sangre/normas , /diagnóstico , Creatina Quinasa/sangre , Femenino , Humanos , Insulina/sangre , Masculino , Persona de Mediana Edad , Sistemas de Atención de Punto , /fisiología , Sensibilidad y Especificidad
15.
PLoS One ; 16(2): e0245914, 2021.
Artículo en Inglés | MEDLINE | ID: covidwho-1088751

RESUMEN

In the emergency of the SARS-CoV-2 pandemic, great efforts were made to quickly provide serology testing to the medical community however, these methods have been introduced into clinical practice without the complete validation usually required by the regulatory organizations. SARS-CoV-2 patient samples (n = 43) were analyzed alongside pre-pandemic control specimen (n = 50), confirmed respiratory infections (n = 50), inflammatory polyarthritis (n = 22) and positive for thyroid stimulating immunoglobulin (n = 30). Imprecision, diagnostic sensitivity and specificity and concordance were evaluated on IgG serologic assays from EuroImmun, Epitope Diagnostics (EDI), Abbott Diagnostics and DiaSorin and a rapid IgG/IgM test from Healgen. EDI and EuroImmun imprecision was 0.02-14.0% CV. Abbott and DiaSorin imprecision (CV) ranged from 5.2%-8.1% and 8.2%-9.6% respectively. Diagnostic sensitivity of the assays was 100% (CI: 80-100%) for Abbott, EDI and EuroImmun and 95% (CI: 73-100%) for DiaSorin at ≥14 days post PCR. Only the Abbott assay had a diagnostic specificity of 100% (CI: 91-100%). EuroImmun cross-reacted in 3 non-SARS-CoV-2 respiratory infections and 2 controls. The DiaSorin displayed more false negative results and cross-reacted in six cases across all conditions tested. EDI had one cross-reactive sample. The Healgen rapid test showed excellent sensitivity and specificity. Overall, concordance of the assays ranged from 76.1% to 97.9%. Serological tests for SARS-CoV-2 showed good analytical performance. The head-to-head analysis of samples revealed differences in results that may be linked to the use of nucleocapsid or spike proteins. The point of care device tested demonstrated adequate performance for antibody detection.


Asunto(s)
/métodos , /inmunología , Anticuerpos Antivirales/sangre , Brasil/epidemiología , /inmunología , /tendencias , Técnicas de Laboratorio Clínico/métodos , Reacciones Cruzadas , Humanos , Inmunoglobulina G/sangre , Inmunoglobulina M/sangre , Pandemias , Sistemas de Atención de Punto , Sensibilidad y Especificidad
16.
Hamostaseologie ; 41(1): 69-75, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: covidwho-1082642

RESUMEN

Physiological fibrinolysis under normal conditions progresses slowly, in contrast to coagulation which is triggered rapidly to stop bleeding and defend against microbial invasion. Methods to detect fibrinolysis abnormalities are less simple and poorly standardized compared with common coagulation tests. Fibrinolysis can be accelerated by preparing euglobulin from plasma to reduce endogenous inhibitors, or by adding plasminogen activators to normal plasma. However, these manipulations complicate interpretation of results and diagnosis of a "fibrinolysis deficit." Many observational studies on antigen levels of fibrinolysis inhibitors, plasminogen activator inhibitor 1 or thrombin-activatable fibrinolysis inhibitor, zymogen or active enzyme have been published. However, conclusions are mixed and there are clear problems with harmonization of results. Viscoelastic methods have the advantage of being rapid and are used as point-of-care tests. They also work with whole blood, allowing the contribution of platelets to be explored. However, there are no agreed protocols for applying viscoelastic methods in acute care for the diagnosis of hyperfibrinolysis or to direct therapy. The emergence of SARS-CoV-2 and the dangers of associated coagulopathy provide new challenges. A common finding in hospitalized patients is high levels of D-dimer fibrin breakdown products, indicative of ongoing fibrinolysis. Well-established problems with D-dimer testing standardization signal that we should be cautious in using results from such tests as prognostic indicators or to target therapies.


Asunto(s)
/fisiopatología , /virología , Fibrinólisis , Humanos , Sistemas de Atención de Punto , /aislamiento & purificación
17.
BMJ Open ; 11(2): e041118, 2021 02 10.
Artículo en Inglés | MEDLINE | ID: covidwho-1079072

RESUMEN

INTRODUCTION: In the context of the COVID-19 pandemic, early identification of patients who are likely to get worse is a major concern. Severity mainly depends on the development of acute respiratory distress syndrome (ARDS) with a predominance of subpleural lesions. Lung point-of-care ultrasonography (L-POCUS) is highly effective in detecting pulmonary peripheral patterns and may be appropriate for examining patients with COVID-19. We suggest that L-POCUS performed during the initial examination may identify patients with COVID-19 who are at a high risk of complicated treatment or unfavourable evolution. METHODS AND ANALYSIS: Point-of-care ultrasonography for risk stratification of non-critical COVID-19 patients on admission is a prospective, multicentre study. Adult patients visiting the emergency department (ED) of participating centres for suspected or confirmed COVID-19 are assessed for inclusion. Included patients have L-POCUS performed within 48 hours following ED admission. The severity of lung damage is assessed using the L-POCUS score based on 36 points for ARDS. Apart from the L-POCUS score assessment, patients are treated as recommended by the WHO. For hospitalised patients, a second L-POCUS is performed at day 5±3. A follow-up is carried out on day 14, and the patient's status according to the Ordinal Scale for Clinical Improvement for COVID-19 from the WHO is recorded.The primary outcome is the rate of patients requiring intubation or who are dead from any cause during the 14 days following inclusion. We will determine the area under the ROC curve of L-POCUS. ETHICS AND DISSEMINATION: The protocol has been approved by the French and Belgian Ethics Committees and is carried out in accordance with the Declaration of Helsinki and Good Clinical Practice guidelines. The study is funding by a grant from the French Health Ministry, and its findings will be disseminated in peer-reviewed journals and at scientific conferences. TRIAL REGISTRATION NUMBER: NCT04338100.


Asunto(s)
/diagnóstico , Sistemas de Atención de Punto , Medición de Riesgo , Ultrasonografía , Adolescente , Servicio de Urgencia en Hospital , Humanos , Estudios Multicéntricos como Asunto , Pandemias , Admisión del Paciente , Estudios Prospectivos
18.
Diabetes Care ; 44(4): 1055-1058, 2021 04.
Artículo en Inglés | MEDLINE | ID: covidwho-1076409

RESUMEN

OBJECTIVE: The use of remote real-time continuous glucose monitoring (CGM) in the hospital has rapidly emerged to preserve personal protective equipment and reduce potential exposures during coronavirus disease 2019 (COVID-19). RESEARCH DESIGN AND METHODS: We linked a hybrid CGM and point-of-care (POC) glucose testing protocol to a computerized decision support system for continuous insulin infusion and integrated a validation system for sensor glucose values into the electronic health record. We report our proof-of-concept experience in a COVID-19 intensive care unit. RESULTS: All nine patients required mechanical ventilation and corticosteroids. During the protocol, 75.7% of sensor values were within 20% of the reference POC glucose with an associated average reduction in POC of 63%. Mean time in range (70-180 mg/dL) was 71.4 ± 13.9%. Sensor accuracy was impacted by mechanical interferences in four patients. CONCLUSIONS: A hybrid protocol integrating real-time CGM and POC is helpful for managing critically ill patients with COVID-19 requiring insulin infusion.


Asunto(s)
Glucemia/análisis , Enfermedad Crítica/terapia , Complicaciones de la Diabetes , Sistemas de Infusión de Insulina , Insulina/administración & dosificación , Tecnología de Sensores Remotos , Anciano , Anciano de 80 o más Años , Algoritmos , Glucemia/metabolismo , Automonitorización de la Glucosa Sanguínea/instrumentación , Automonitorización de la Glucosa Sanguínea/métodos , /complicaciones , Complicaciones de la Diabetes/sangre , Complicaciones de la Diabetes/tratamiento farmacológico , Equipos y Suministros , Femenino , Humanos , Unidades de Cuidados Intensivos , Masculino , Persona de Mediana Edad , Sistemas de Atención de Punto , Prueba de Estudio Conceptual , Tecnología de Sensores Remotos/instrumentación
19.
Biotechniques ; 69(4): 317-325, 2020 10.
Artículo en Inglés | MEDLINE | ID: covidwho-1067502

RESUMEN

PCR has become one of the most valuable techniques currently used in bioscience, diagnostics and forensic science. Here we review the history of PCR development and the technologies that have evolved from the original PCR method. Currently, there are two main areas of PCR utilization in bioscience: high-throughput PCR systems and microfluidics-based PCR devices for point-of-care (POC) applications. We also discuss the commercialization of these techniques and conclude with a look into their modifications and use in innovative areas of biomedicine. For example, real-time reverse transcription PCR is the gold standard for SARS-CoV-2 diagnoses. It could also be used for POC applications, being a key component of the sample-to-answer system.


Asunto(s)
Reacción en Cadena de la Polimerasa/métodos , Animales , Betacoronavirus/genética , Betacoronavirus/aislamiento & purificación , Técnicas de Laboratorio Clínico/instrumentación , Técnicas de Laboratorio Clínico/métodos , Infecciones por Coronavirus/diagnóstico , Infecciones por Coronavirus/virología , Diseño de Equipo , Humanos , Técnicas Analíticas Microfluídicas/instrumentación , Técnicas Analíticas Microfluídicas/métodos , Pandemias , Neumonía Viral/diagnóstico , Neumonía Viral/virología , Sistemas de Atención de Punto , Reacción en Cadena de la Polimerasa/instrumentación
20.
Expert Rev Mol Diagn ; 21(1): 43-61, 2021 01.
Artículo en Inglés | MEDLINE | ID: covidwho-1066147

RESUMEN

Introduction: Over the past decade, loop-mediated isothermal amplification (LAMP) technology has played an important role in molecular diagnostics. Amongst numerous nucleic acid amplification assays, LAMP stands out in terms of sample-to-answer time, sensitivity, specificity, cost, robustness, and accessibility, making it ideal for field-deployable diagnostics in resource-limited regions.Areas covered: In this review, we outline the front-end LAMP design practices for point-of-care (POC) applications, including sample handling and various signal readout methodologies. Next, we explore existing LAMP technologies that have been validated with clinical samples in the field. We summarize recent work that utilizes reverse transcription (RT) LAMP to rapidly detect SARS-CoV-2 as an alternative to standard PCR protocols. Finally, we describe challenges in translating LAMP from the benchtop to the field and opportunities for future LAMP assay development and performance reporting.Expert opinion: Despite the popularity of LAMP in the academic research community and a recent surge in interest in LAMP due to the COVID-19 pandemic, there are numerous areas for improvement in the fundamental understanding of LAMP, which are needed to elevate the field of LAMP assay development and characterization.


Asunto(s)
/diagnóstico , Técnicas de Diagnóstico Molecular , Técnicas de Amplificación de Ácido Nucleico , Pruebas en el Punto de Atención , /aislamiento & purificación , Colorimetría , Reacciones Falso Positivas , Fluorescencia , Humanos , Límite de Detección , Pandemias , Sistemas de Atención de Punto , Reacción en Cadena de la Polimerasa/métodos , ARN Viral/aislamiento & purificación , Sensibilidad y Especificidad
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