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1.
BMJ Case Rep ; 13(10)2020 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-33130584

RESUMO

During the global pandemic of COVID-19 accurate diagnosis of the infection by demonstrating SARS-CoV-2 viral RNA by PCR in specimens is crucial for therapeutic and preventative interventions. There have been instances where nasal and throat swabs have been negative despite the patient having typical clinical and radiological findings compatible with the disease. We report a case of a man in his late 50s, brought to the hospital following a cardiac arrest and prolonged unsuccessful resuscitation. The history was typical for COVID-19 with fever for 10 days and worsening shortness of breath. His throat and nasal swabs (after death) were negative for SARS-CoV-2. A limited diagnostic autopsy was performed after 27 days, and lung swabs confirmed presence of SARS-CoV-2. This case highlights the importance of lung swabs when initial upper respiratory tract swabs are negative and proves that the virus can be detected from dead human tissue almost a month later.


Assuntos
Técnicas de Laboratório Clínico/métodos , Infecções por Coronavirus/diagnóstico , DNA Viral/análise , Pulmão/virologia , Parada Cardíaca Extra-Hospitalar/terapia , Faringe/virologia , Pneumonia Viral/diagnóstico , Autopsia , Reanimação Cardiopulmonar/métodos , Serviço Hospitalar de Emergência , Reações Falso-Negativas , Evolução Fatal , Humanos , Masculino , Pessoa de Meia-Idade , Pandemias , Reação em Cadeia da Polimerase/métodos
2.
Virulence ; 11(1): 1394-1401, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33073676

RESUMO

We previously reported that sputum induction was more sensitive than throat swabs for the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in two convalescent coronavirus disease 2019 (COVID-19) patients; however, the value and safety of induced sputum testing require further study. We conducted a prospective multi-center cross-sectional study to compare induced sputum to throat swabs for SARS-CoV-2 detection. Confirmed COVID-19 patients from six hospitals in six cities across China who received one or more negative RT-PCR result for SARS-CoV-2 were enrolled, and paired specimens (induced sputum and throat swabs; 56 cases) were assayed. In three paired samples, both the induced sputum and throat swabs were positive for SARS-CoV-2. The positive rate for induced sputum was significantly higher than for throat swabs both overall (28.6% vs 5.4%, respectively; p < 0.01). Patients were divided according to time span from onset of illness to sample collection into the more-than-30-day (n = 26) and less-than-30-day (n = 30) groups. The positive rate for induced sputum was also significantly higher than for throat swabs in the less-than-30-day group (53.3% vs 10.0%, respectively; p < 0.001). For the more-than-30-day group, all paired samples were negative for SARS-CoV-2. Blood oxygen saturation, respiratory rate, and heart rate remained stable during sputum induction and no staff were infected. Because induced sputum is more reliable and has a lower false-negative rate than throat swabs, we believe induced sputum is more useful for the confirmation of COVID-19 and is safer as a criterion for release from quarantine.


Assuntos
Betacoronavirus/isolamento & purificação , Técnicas de Laboratório Clínico/métodos , Infecções por Coronavirus/diagnóstico , Pneumonia Viral/diagnóstico , Escarro/virologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Betacoronavirus/genética , Líquido da Lavagem Broncoalveolar/virologia , China , Estudos Transversais , Reações Falso-Negativas , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pandemias , Estudos Prospectivos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Sensibilidade e Especificidade , Adulto Jovem
5.
Euro Surveill ; 25(39)2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-33006300

RESUMO

We found that a single nucleotide polymorphism (SNP) in the nucleoprotein gene of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from a patient interfered with detection in a widely used commercial assay. Some 0.2% of the isolates in the EpiCoV database contain this SNP. Although SARS-CoV-2 was still detected by the other probe in the assay, this underlines the necessity of targeting two independent essential regions of a pathogen for reliable detection.


Assuntos
Betacoronavirus/genética , Técnicas de Laboratório Clínico , Infecções por Coronavirus/diagnóstico , Nucleoproteínas/genética , Pandemias , Pneumonia Viral/diagnóstico , Mutação Puntual , Polimorfismo de Nucleotídeo Único , RNA Viral/genética , Reação em Cadeia da Polimerase em Tempo Real , Proteínas Virais/genética , Sequência de Bases , Betacoronavirus/isolamento & purificação , Técnicas de Laboratório Clínico/métodos , Busca de Comunicante , Infecções por Coronavirus/virologia , Primers do DNA , Erros de Diagnóstico , Reações Falso-Negativas , Feminino , Genes Virais , Humanos , Pessoa de Meia-Idade , Nasofaringe/virologia , Nucleoproteínas/análise , Filogenia , Pneumonia Viral/virologia , Reação em Cadeia da Polimerase em Tempo Real/métodos , Romênia , Doença Relacionada a Viagens , Proteínas Virais/análise
6.
J Med Case Rep ; 14(1): 191, 2020 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-33028403

RESUMO

BACKGROUND: Determining the infectiousness of patients with coronavirus disease 2019 is crucial for patient management. Medical staff usually refer to the results of reverse transcription polymerase chain reaction tests in conjunction with clinical symptoms and computed tomographic images. CASE PRESENTATION: We report a case of a 62-year-old Japanese man who twice had positive and negative test results by polymerase chain reaction for severe acute respiratory syndrome coronavirus 2 over 48 days of hospitalization, including in intensive care. His respiratory symptoms and computed tomographic imaging findings consistent with coronavirus disease 2019 improved following initial intensive care, and the result of his polymerase chain reaction test became negative 3 days before discharge from the intensive care unit. However, 4 days after this first negative result, his polymerase chain reaction test result was positive again, and another 4 days later, he had a negative result once more. Eight days after the second polymerase chain reaction negative test result, the patient's test result again became positive. Finally, his polymerase chain reaction results were negative 43 days after his first hospitalization. CONCLUSIONS: This case emphasizes the importance of repeat polymerase chain reaction testing and diagnosis based on multiple criteria, including clinical symptoms and computed tomographic imaging findings. Clinical staff should consider that a negative result by polymerase chain reaction does not necessarily certify complete coronavirus disease 2019 recovery.


Assuntos
Betacoronavirus/isolamento & purificação , Técnicas de Laboratório Clínico/métodos , Infecções por Coronavirus , Pulmão/diagnóstico por imagem , Pandemias , Pneumonia Viral , Avaliação de Sintomas/métodos , Tomada de Decisão Clínica , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/fisiopatologia , Infecções por Coronavirus/terapia , Cuidados Críticos/métodos , Reações Falso-Negativas , Humanos , Masculino , Pessoa de Meia-Idade , Pneumonia Viral/diagnóstico , Pneumonia Viral/fisiopatologia , Pneumonia Viral/terapia , Tomografia Computadorizada por Raios X/métodos , Resultado do Tratamento
7.
PLoS One ; 15(10): e0239342, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33027314

RESUMO

INTRODUCTION: Tuberculosis disease is the leading cause of death worldwide along with HIV/AIDS. Sputum smear microscopy plays an essential role for initial TB diagnosis and treatment follow up. But, misdiagnosis of sputum smear microscopy revealed a high economical crisis and missing of active TB cases. This study was aimed to determine blinded rechecking of sputum smear microscopy performance in public health facilities in Tigray region, Northern Ethiopia. MATERIALS AND METHODS: A cross sectional retrospective study was conducted from January, 2017 to December, 2018 year. Data was collected retrospectively using electronic and paper based in Tigray health research institute. The data was analyzed using the SPSS version 25 software. The sensitivity, specificity, positive predictive value, and negative predictive value of the smear readings were calculated using 2X2 contingency table. The reading agreement between the microscopic center and reference center was determined using kappa statistics. RESULTS: A total of 23,456 blinded rechecked smear results were reviewed. In average, the performances of sputum smear quality were 61%, 68%, 64%, 66%, 62% and 75% for specimen quality, staining quality, smear size, smear thickness, smear evenness and smear cleanliness respectively. Of the total error (0.48%) reported, 0.25%, 0.19% and 0.085% were false positive, false negative and quantification errors respectively. The concordance rate of health facilities for smear reading was increased to 90% by the end of 2018. Overall, the sensitivity, specificity, PPV, and NPV of the smear readings were 95%, 99.7%, 93% and 99.8% respectively. Likewise, the smear reading agreement was also perfect with kappa value, 0.87. CONCLUSION: The overall performance of public health facilities for blinded rechecking of smear microscopy was satisfactory. But, the high false positive and false negative errors found calls for continuous evaluation and monitoring of the health facilities by reference center.


Assuntos
Microscopia/métodos , Escarro/microbiologia , Tuberculose/diagnóstico , Estudos Transversais , Etiópia , Reações Falso-Negativas , Humanos , Microscopia/normas , Controle de Qualidade , Estudos Retrospectivos , Sensibilidade e Especificidade
8.
Emerg Microbes Infect ; 9(1): 1955-1957, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32869728

RESUMO

The case refers to a 51-year-old symptomatic man with a new SARS-CoV-2 RNA positive nasopharyngeal swab after two negative ones and the lack of significant development of antibody response measured by different diagnostic serological test. Our case underlines that a discrepancy between clinical course of SARS-CoV-2 infection and results from diagnostic tests may exist. This concept is rapidly emerging and supports the need for a deep knowledge of available and "in development" tests for a correct interpretation of their findings.


Assuntos
Anticorpos Antivirais/sangue , Betacoronavirus/imunologia , Betacoronavirus/isolamento & purificação , Infecções por Coronavirus/diagnóstico , Imunoglobulina G/sangue , Pneumonia Viral/diagnóstico , Infecções por Coronavirus/tratamento farmacológico , Ensaio de Imunoadsorção Enzimática , Reações Falso-Negativas , Humanos , Hidroxicloroquina/uso terapêutico , Masculino , Pessoa de Meia-Idade , Pandemias , Pneumonia Viral/tratamento farmacológico , Reação em Cadeia da Polimerase , Quarentena , Recidiva , Testes Sorológicos , Carga Viral
9.
Acta Biomed ; 91(3): e2020003, 2020 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-32921701

RESUMO

BACKGROUND: The COVID-19 outbreak is now a pandemic disease reaching as much as 210 countries worldwide with more than 2.5 million infected people and nearly 200.000 deaths. Amplification of viral RNA by RT-PCR represents the gold standard for confirmation of infection, yet it showed false-negative rates as large as 15-20% which may jeopardize the effect of the restrictive measures taken by governments. We previously showed that several hematological parameters were significantly different between COVID-19 positive and negative patients. Among them aspartate aminotransferase and lactate dehydrogenase had predictive values as large as 90%. Thus a combination of RT-PCR and blood tests could reduce the false-negative rate of the genetic test. METHODS: We retrospectively analyzed 24 patients showing multiple and inconsistent RT-PCR, test during their first hospitalization period, and compared the genetic tests results with their AST and LDH levels. RESULTS: We showed that when considering the hematological parameters, the RT-PCR false-negative rates were reduced by almost 4-fold. CONCLUSIONS: The study represents a preliminary work aiming at the development of strategies that, by combining RT-PCR tests with routine blood tests, will lower or even abolish the rate of RT-PCR false-negative results and thus will identify, with high accuracy, patients infected by COVID-19.


Assuntos
Betacoronavirus/genética , Infecções por Coronavirus/diagnóstico , Pandemias , Pneumonia Viral/diagnóstico , RNA Viral/análise , Reação em Cadeia da Polimerase em Tempo Real/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Aspartato Aminotransferases/sangue , Biomarcadores/sangue , Infecções por Coronavirus/sangue , Infecções por Coronavirus/epidemiologia , Diagnóstico Diferencial , Reações Falso-Negativas , Feminino , Seguimentos , Testes Hematológicos/métodos , Humanos , Itália/epidemiologia , L-Lactato Desidrogenase/sangue , Masculino , Pessoa de Meia-Idade , Pneumonia Viral/sangue , Pneumonia Viral/epidemiologia , Reprodutibilidade dos Testes , Estudos Retrospectivos
10.
Biomed Res Int ; 2020: 2721381, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32884938

RESUMO

Introduction: Emergency department (ED) triage regarding infection with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is challenging. During the coronavirus disease 2019 (COVID-19) outbreak in Germany, the diagnostic outcomes of critically ill patients admitted to the resuscitation room in the ED of our academic 754-bed hospital should be analyzed. Methods: All resuscitation room patients between March 1st and April 15th 2020 were included in this retrospective study. Every patient with suspicion of SARS-CoV-2 infection received a pharyngeal swab for real-time polymerase chain reaction (rt-PCR), divided in the clinical subgroups of "highly suspicious for COVID-19" and "COVID-19 as differential diagnosis." All respiratory and infectious symptoms were included as at least "differential diagnosis" as an expanded suspicion strategy. Results: Ninety-five patients were included (trauma n = 14, critically ill n = 81). Of 3 highly suspicious patients, 2 had rt-PCR positive pharyngeal swabs. In 39 patients, COVID-19 was defined as differential diagnosis, and 3 were positive for SARS-CoV-2. Of them, pharyngeal swabs were positive in 1 case, while in 2 cases, only tracheal fluid was rt-PCR positive while the pharyngeal swabs were negative. In one of these 2 cases, chest computed tomography (CT) was also negative for ground-glass opacities but showed a pulmonary abscess and pulmonary embolism. Conclusion: We recommend an expanded suspicion strategy for COVID-19 due to unexpected diagnostic outcomes. Personal protective equipment should be used in every resuscitation room operation due to unexpected cases and initial knowledge gaps. Furthermore, tracheal fluid should be tested for SARS-CoV-2 in every intubated patient due to cases with negative pharyngeal swabs and negative chest CT.


Assuntos
Betacoronavirus , Técnicas de Laboratório Clínico/métodos , Infecções por Coronavirus/diagnóstico , Pneumonia Viral/diagnóstico , Idoso , Idoso de 80 Anos ou mais , Infecções por Coronavirus/diagnóstico por imagem , Infecções por Coronavirus/epidemiologia , Estado Terminal , Diagnóstico Diferencial , Surtos de Doenças , Serviço Hospitalar de Emergência , Reações Falso-Negativas , Feminino , Alemanha/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Pandemias , Pneumonia Viral/diagnóstico por imagem , Pneumonia Viral/epidemiologia , RNA Viral/genética , RNA Viral/isolamento & purificação , Reação em Cadeia da Polimerase em Tempo Real , Ressuscitação , Estudos Retrospectivos , Tomografia Computadorizada por Raios X , Triagem
11.
Rev. Hosp. Ital. B. Aires (2004) ; 40(3): 117-125, sept. 2020. ilus, tab
Artigo em Espanhol | LILACS | ID: biblio-1129078

RESUMO

En diciembre de 2019 se identificó el virus SARS-CoV-2, cuya rápida propagación global puso en estado de emergencia al mundo entero, llevando al ser humano a una situación sin antecedente cercano. El objetivo de esta revisión es describir los métodos diagnósticos utilizados actualmente para identificar la infección por SARS-CoV-2. Las manifestaciones clínicas y el espectro imagenológico de la enfermedad son muy inespecíficos y no permiten realizar un diagnóstico certero. Por esta razón, es esencial una apropiada toma de muestra respiratoria en el momento y sitio anatómico adecuado para un diagnóstico preciso de COVID-19. La técnica de muestreo más utilizada es el hisopado nasofaríngeo y la prueba diagnóstica más fiable se basa en la retrotranscripción seguida por reacción en cadena de la polimerasa en tiempo real (RT-PCR). No obstante, existen otras técnicas moleculares, como también tests serológicos para detectar anticuerpos o fragmentos antigénicos del SARS-CoV-2. Más allá de la precisión diagnóstica, es importante tener en cuenta la probabilidad basal (pretest) para interpretar correctamente el resultado obtenido y aislar aquellos posibles falsos negativos. Con el objetivo de evitar la saturación del sistema de salud es imprescindible contar con información y métodos diagnósticos precisos para detectar tempranamente los focos de infección y reducir la transmisión comunitaria, utilizando eficazmente los diferentes recursos diagnósticos. (AU)


In December 2019, the SARS-CoV-2 virus was identified for the first time, whose rapid global spread put the entire world in a state of emergency, leading humans to an unprecedented situation with no immediate history. The main purpose of this review is to describe the diagnostic methods currently used to identify SARS-CoV-2 infection. The clinical manifestations and the imaging spectrum of the disease are nonspecific and do not allow an accurate diagnosis to be made. For this reason, an appropriate respiratory sampling at the right time and anatomical site is essential for an accurate diagnosis of COVID-19. The most widely used sampling technique is nasopharyngeal swab, and the most reliable diagnostic test is by reverse transcription followed by real-time polymerase chain reaction (RT-PCR). However, there are other molecular techniques, as well as serological tests to detect antibodies or antigenic fragments of SARS-CoV-2. Beyond the diagnostic precision, it is important to take into account the baseline probability (pre-test) to correctly interpret the result obtained and isolate those possible false negatives. In order to avoid saturation of the health system, it is essential to have accurate information and diagnostic methods to detect outbreaks of infection in early stages and to reduce communitary transmission, making effective use of the various diagnostic resources. Coronavirus infections/diagnosis, viral/diagnosis, pandemics, clinical laboratory techniques, real-time polymerase chain reaction, antigens, viral/analysis. (AU)


Assuntos
Humanos , Testes Sorológicos/métodos , Infecções por Coronavirus/diagnóstico , Reação em Cadeia da Polimerase em Tempo Real/métodos , Argentina , Pneumonia Viral/diagnóstico , Testes Sorológicos/estatística & dados numéricos , Reação em Cadeia da Polimerase/métodos , Reação em Cadeia da Polimerase/estatística & dados numéricos , Infecções por Coronavirus/fisiopatologia , Infecções por Coronavirus/prevenção & controle , Infecções por Coronavirus/diagnóstico por imagem , Reações Falso-Negativas , Reações Falso-Positivas , Reação em Cadeia da Polimerase em Tempo Real/estatística & dados numéricos , Betacoronavirus
12.
Medicine (Baltimore) ; 99(33): e21085, 2020 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-32871979

RESUMO

The lymph nodal invasion diagnosis is critical for therapeutic-decision and follows up in gastric cancer. However, the number of nodes to be examined for nodal invasion diagnosis is still under controversy, and the model for quantifying risk of missing positive node is currently not reported yet. We analyzed the nodal invasion status of 13,857 gastric cancer samples with records of primary tumor stage, the number of examined and positive lymph nodes in the surveillance, epidemiology, and end results (SEER) database, fitting a beta-binomial model. The nodes need to be examined with different primary tumor stage were determined based on the model. Overall, examining 11 lymph nodes reduces the probability of missing positive nodes to <10%, and the currently median nodes dissected is adequate (12 nodes). While the number of nodes demands to be dissected for T1, T2, T3, and T4 subgroups are 6, 19, 40, and 66, respectively. The currently implemented median value for these samples was 12, 12, 13, and 16, separately. It implies that the number of nodes to be examined is sufficient for early gastric cancer (T1), but it is inadequate for middle and advanced gastric cancer (T2-T3). The clinical significance of nodal staging score was validated with survival information. In summary, we first quantified the lymph nodes to be examined during surgery using a beta-binomial model, and validated with survival information.


Assuntos
Linfonodos/patologia , Metástase Linfática/diagnóstico , Metástase Linfática/patologia , Estadiamento de Neoplasias/métodos , Neoplasias Gástricas/diagnóstico , Neoplasias Gástricas/patologia , Reações Falso-Negativas , Feminino , Humanos , Linfonodos/cirurgia , Masculino , Pessoa de Meia-Idade , Modelos Estatísticos , Probabilidade , Estudos Retrospectivos , Programa de SEER , Sensibilidade e Especificidade , Neoplasias Gástricas/epidemiologia , Neoplasias Gástricas/cirurgia , Análise de Sobrevida
13.
F1000Res ; 9: 671, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32968484

RESUMO

Institutions such as hospitals and nursing or long-stay residential homes accommodate individuals at considerable risk of mortality should they acquire SARS-CoV-2 infection. In these settings, polymerase chain reaction tests play a central role in infection prevention and control. Here, we argue that both false negative and false positive tests are possible and that careful consideration of the prior probability of infection and of test characteristics are needed to prevent harm. We outline evidence suggesting that regular systematic testing of asymptomatic and pre-symptomatic individuals could play an important role in reducing transmission of SARS-CoV-2 within institutions. We discuss how such a programme might be organised, arguing that frequent testing and rapid reporting of results are particularly important. We highlight studies demonstrating that polymerase chain reaction testing of pooled samples can be undertaken with acceptable loss of sensitivity, and advocate such an approach where test capacity is limited. We provide an approach to calculating the most efficient pool size. Given the current limitations of tests for SARS-CoV-2 infection, physical distancing and meticulous infection prevention and control will remain essential in institutions caring for vulnerable people.


Assuntos
Infecções por Coronavirus/diagnóstico , Pneumonia Viral/diagnóstico , Reação em Cadeia da Polimerase , Betacoronavirus , Técnicas de Laboratório Clínico , Reações Falso-Negativas , Reações Falso-Positivas , Hospitais , Humanos , Casas de Saúde , Pandemias
14.
Virus Res ; 289: 198147, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32866537

RESUMO

BACKGROUND: To investigate the clinical significance, viral shedding duration and viral load dynamics of positive fecal SARS-CoV-2 signals in COVID-19. METHODS: COVID-19 patients were included. SARS-CoV-2 RNA was tested in stool and respiratory specimens until two sequential negative results were obtained. Clinical, laboratory and imaging data were recorded. RESULTS: Of the 69 COVID-19 patients, 20 (28.99 %) had positive fecal viral tests who were younger, had lower C-reactive protein (CRP) and fibrinogen (FIB) levels on admission (all P < 0.05), and showed more improvement and less progression on chest CT during recovery. The median duration of positive viral signals was significantly longer in stool samples than in respiratory samples (P < 0.05). In spite of the negative oropharyngeal swabs, eleven patients were tested positive for viral RNA in stool specimens, with their fecal SARS-CoV-2 RNA Ct (cycle threshold) values reaching 25-27. 6 of these 11 patients' Ct values rebounded. CONCLUSION: SARS-CoV-2 RNA in stool specimens was associated with a milder condition and better recovery of chest CT results while the median duration of SARS-CoV-2 RNA persistence was significantly longer in fecal samples than in oropharyngeal swabs. The fecal viral load easily reached a high level and rebounded even though respiratory signals became negative.


Assuntos
Betacoronavirus/isolamento & purificação , Infecções por Coronavirus/virologia , Fezes/virologia , Pneumonia Viral/virologia , RNA Viral/análise , Eliminação de Partículas Virais , Adulto , Proteína C-Reativa/análise , Infecções por Coronavirus/sangue , Infecções por Coronavirus/diagnóstico por imagem , Infecções por Coronavirus/transmissão , Diarreia/etiologia , Diarreia/virologia , Reações Falso-Negativas , Feminino , Fibrinogênio/análise , Humanos , Pulmão/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Orofaringe/virologia , Pandemias , Pneumonia Viral/sangue , Pneumonia Viral/diagnóstico por imagem , Pneumonia Viral/transmissão , Prognóstico , Estabilidade de RNA , Reação em Cadeia da Polimerase em Tempo Real , Avaliação de Sintomas , Carga Viral
16.
PLoS One ; 15(9): e0238749, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32886699

RESUMO

INTRODUCTION: False-negative malaria rapid diagnostic test (RDT) results amongst symptomatic malaria patients are detrimental as they could lead to ineffective malaria case management. This study determined the nationwide contribution of parasites with Pfhrp2 and Pfhrp 3 gene deletions to false negative malaria RDT results in Ghana. METHODS: This was a cross sectional study where whole blood (~2 ml) was collected from patients presenting with malaria symptoms at 100 health facilities in all the regions in Ghana from May to August 2018. An aliquot of the blood was used to prepare thin and thick blood smears, filter paper blood spots (DBS) and spot a PfHRP 2 RDT kit. The remaining blood was separated into plasma and blood cells and stored at -20°C. Plasmodium parasite density and species identity was estimated from the blood smears. Plasmodium falciparum specific 18S rRNA PCR, merozoite surface protein (msp 1) and glutamate rich protein (glurp) gene PCR were used to identify P. falciparum positive samples, which were subjected to Pfhrp 2/3 exon1-2 and exon2 genotyping. RESULTS: Of the 2,860 microscopically P. falciparum positive patients analyzed, 134 (4.69%) had false negative P. falciparum specific RDT results. Samples for PCR analysis was available for 127 of the false negative patients, and the analysis identified 116 (91.3%) as positive for P. falciparum. Only 58.1% (79/116) of the false negative RDT samples tested positive by msp 1 and glurp PCR. Genotyping of exon 1-2 and exon 2 of the Pfhrp 2 gene identified 12.9% (10/79) and 39.5% (31/79) of samples respectively to have deletions. Genotyping exon 1-2 and exon 2 of the Pfhrp 3 gene identified 15.2% (12/79) and 40.5% (32/79) of samples respectively to have deletions. Only 5% (4/79) of the false negative samples had deletions in both exon 1-2 and exon 2 of the Pfhrp 2 gene. Out of the 49 samples that tested positive for aldolase by luminex, 32.6% (16/49) and) had deletions in Pfhrp 2 exon 2 and 2% (1/49) had deletions in both exon 2 and exon 1-2 of the Pfhrp 2 gene. CONCLUSIONS: The low prevalence of false negative RDT test results provides assurance that PfHRP 2 based malaria RDT kits remain effective in diagnosing symptomatic malaria patients across all the Regions of Ghana. Although there was a low prevalence of parasites with deletions in exon 2 and exon 1-2 of the Pfhrp 2 gene the prevalence of parasites with deletions in Pfhrp 2 exon 2 was about a third of the false negative RDT results. The need to ensure rapid, accurate and reliable malaria diagnosis requires continuous surveillance of parasites with Pfhrp 2 gene deletions.


Assuntos
Antígenos de Protozoários/genética , Antígenos de Protozoários/metabolismo , Deleção de Genes , Malária Falciparum/diagnóstico , Plasmodium falciparum/genética , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo , Adulto , Antígenos de Protozoários/imunologia , Reações Falso-Negativas , Feminino , Técnicas de Genotipagem , Gana/epidemiologia , Humanos , Malária Falciparum/epidemiologia , Masculino , Pessoa de Meia-Idade , Plasmodium falciparum/imunologia , Plasmodium falciparum/fisiologia , Adulto Jovem
17.
Virulence ; 11(1): 1250-1256, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32921249

RESUMO

The cause of some patients with negative RT-PCR results experienced turn-positive after treatment remains unclear. In addition, understanding the correlation between changes in clinical data in the course of COVID-19 and treatment outcomes is of great importance in determining the prognosis of COVID-19. To perform cause analysis of RT-PCR turn-positive and the effective screening factors related to treatment outcome in COVID-19. Clinical data, including clinical manifestations, laboratory tests, radiography results, treatment methods and outcomes, were retrospectively collected and analyzed from January to March 2020 in Renmin Hospitals of Wuhan University. 116 COVID-19 patients (40 in recurrent group, 29 in recovered group and 47 in unrecovered group) were recruited. In the recurrent group, white blood cell, Neutrophils, prothrombin time, activated partial thromboplastin time, CD3, CD4, CD8, ratio of CD4/CD8, IgG and C4 complement were of significant difference among the baseline, negative and turn-positive time points. CD19 and CT scan results were found notable difference between recurrent group and recovered group. Odds from CD3, CD4, CD8, CD19, IgM, C3 complement, C4 complement and CT scan results validated associations with clinical outcomes of COVID-19. The so-called recurrence in some COVID-19 patients may be due to the false-negative of nucleic acid test results from nasopharyngeal swabs. Levels of CD3, CD4, CD8, CD19, IgM, C3 complement, C4 complement and CT results were significantly correlated with the outcome of COVID-19. The cellular immunity test could be beneficial to further screen the reliability of RT-PCR test on the basis of CT images.


Assuntos
Betacoronavirus , Técnicas de Laboratório Clínico , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/terapia , Pneumonia Viral/diagnóstico , Pneumonia Viral/terapia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Adulto , Betacoronavirus/imunologia , Betacoronavirus/patogenicidade , China/epidemiologia , Estudos de Coortes , Infecções por Coronavirus/epidemiologia , Reações Falso-Negativas , Feminino , Humanos , Imunidade Celular , Pulmão/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Pandemias , Pneumonia Viral/epidemiologia , Prognóstico , Recidiva , Estudos Retrospectivos , Fatores de Risco , Tomografia Computadorizada por Raios X , Resultado do Tratamento , Virulência
18.
N Z Med J ; 133(1519): 81-88, 2020 07 31.
Artigo em Inglês | MEDLINE | ID: mdl-32777798

RESUMO

AIM: The diagnostic sensitivity of the SARS-CoV-2 real time reverse transcription polymerase chain reaction (RT-PCR) test has not been determined. This has led to a degree of uncertainty in the interpretation of results, particularly in patients tested repeatedly. The aim of this study was to explore the characteristics of patients who initially tested negative, and subsequently tested positive for SARS-CoV-2. METHODS: This retrospective observational study utilised data from the LabPlus Virology laboratory, Auckland City Hospital, to identify cases (hospital and community) with initial negative and subsequent positive SARS-CoV-2 RT-PCR results. Their clinical and laboratory characteristics were summarised. RESULTS: From 1 February to 13 April a total of 20,089 samples were received for SARS-CoV-2 testing. Of 2,011 samples from patients with multiple tests, 25 samples were positive. Nine samples were from patients who initially tested negative then tested positive. Reasons for the initial negative test results, which were all from upper respiratory tract samples, included pre-symptomatic presentation or late presentation. All patients had significant risk factors and ongoing or evolving symptoms, which warranted repeat testing. CONCLUSION: Few patients had discordant test results for SARS-CoV-2 RT-PCR. For patients who have a significant risk factor and a negative test result, repeat testing should be performed.


Assuntos
Betacoronavirus/isolamento & purificação , Técnicas de Laboratório Clínico , Infecções por Coronavirus , Pandemias , Pneumonia Viral , Doenças Assintomáticas/epidemiologia , Técnicas de Laboratório Clínico/métodos , Técnicas de Laboratório Clínico/normas , Técnicas de Laboratório Clínico/estatística & dados numéricos , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/fisiopatologia , Diagnóstico Diferencial , Reações Falso-Negativas , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Nova Zelândia/epidemiologia , Pneumonia Viral/diagnóstico , Pneumonia Viral/epidemiologia , Pneumonia Viral/fisiopatologia , Reprodutibilidade dos Testes , Estudos Retrospectivos , Medição de Risco , Fatores de Risco
19.
Dan Med J ; 67(9)2020 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-32800072

RESUMO

INTRODUCTION: As the coronavirus disease 2019 (COVID-19) epidemic evolves and test strategies change, understanding the concepts of testing (gold standard and test performance measures) becomes essential. The challenge of any novel disease is that the gold standard has yet to be defined. METHODS: We reanalysed published data on real-time reverse transcription quantitative polymerase chain reaction (RT-qPCR) of severe acute respiratory syndrome coronavirus-2 to illustrate how predictive values vary with disease prevalence, sensitivity (set to values between 30% and 95%) and specificity (set to 99% or 99.98%). We used published data on chest CT and RT-qPCR to examine the potential of latent class analysis to estimate the sensitivity and specificity of RT-qPCR when no single gold standard exists. RESULTS: For the various sensitivity values, the negative predictive value of a RT-qPCR test remained above 92% until a COVID-19 prevalence of > 10%. The positive predictive value (PPV) was more variable. For a sensitivity of 95% and a specificity of 99%, the PPV was less-than 10% at a prevalence of 0.1%, increasing to about 90% at a prevalence of 10%. This improved to a PPV of 85% and almost 100%, respectively, when specificity increased to 99.98%. In a restricted latent class analysis, the sensitivity was 97.1% and the specificity was 99.9%, which is similar to figures from the Danish Health Authority. However, derived predictive values depended on model specification. CONCLUSIONS: A high risk of false-positives should be considered when extending the testing strategy, whereas false-negatives may occur during local outbreaks. This may have consequences for, e.g., containment strategies and research. A confirmatory test (e.g., demonstrating seroconversion or repeated RT-qPCR) may be warranted. FUNDING: none. TRIAL REGISTRATION: not relevant.


Assuntos
Betacoronavirus/genética , Infecções por Coronavirus/diagnóstico , DNA Viral/análise , Publicações Periódicas como Assunto , Pneumonia Viral/diagnóstico , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Infecções por Coronavirus/virologia , Reações Falso-Negativas , Humanos , Pandemias , Pneumonia Viral/virologia
20.
Cochrane Database Syst Rev ; 8: CD013705, 2020 08 26.
Artigo em Inglês | MEDLINE | ID: mdl-32845525

RESUMO

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the resulting COVID-19 pandemic present important diagnostic challenges. Several diagnostic strategies are available to identify or rule out current infection, identify people in need of care escalation, or to test for past infection and immune response. Point-of-care antigen and molecular tests to detect current SARS-CoV-2 infection have the potential to allow earlier detection and isolation of confirmed cases compared to laboratory-based diagnostic methods, with the aim of reducing household and community transmission. OBJECTIVES: To assess the diagnostic accuracy of point-of-care antigen and molecular-based tests to determine if a person presenting in the community or in primary or secondary care has current SARS-CoV-2 infection. SEARCH METHODS: On 25 May 2020 we undertook electronic searches in the Cochrane COVID-19 Study Register and the COVID-19 Living Evidence Database from the University of Bern, which is updated daily with published articles from PubMed and Embase and with preprints from medRxiv and bioRxiv. In addition, we checked repositories of COVID-19 publications. We did not apply any language restrictions. SELECTION CRITERIA: We included studies of people with suspected current SARS-CoV-2 infection, known to have, or not to have SARS-CoV-2 infection, or where tests were used to screen for infection. We included test accuracy studies of any design that evaluated antigen or molecular tests suitable for a point-of-care setting (minimal equipment, sample preparation, and biosafety requirements, with results available within two hours of sample collection). We included all reference standards to define the presence or absence of SARS-CoV-2 (including reverse transcription polymerase chain reaction (RT-PCR) tests and established clinical diagnostic criteria). DATA COLLECTION AND ANALYSIS: Two review authors independently screened studies and resolved any disagreements by discussion with a third review author. One review author independently extracted study characteristics, which were checked by a second review author. Two review authors independently extracted 2x2 contingency table data and assessed risk of bias and applicability of the studies using the QUADAS-2 tool. We present sensitivity and specificity, with 95% confidence intervals (CIs), for each test using paired forest plots. We pooled data using the bivariate hierarchical model separately for antigen and molecular-based tests, with simplifications when few studies were available. We tabulated available data by test manufacturer. MAIN RESULTS: We included 22 publications reporting on a total of 18 study cohorts with 3198 unique samples, of which 1775 had confirmed SARS-CoV-2 infection. Ten studies took place in North America, two in South America, four in Europe, one in China and one was conducted internationally. We identified data for eight commercial tests (four antigen and four molecular) and one in-house antigen test. Five of the studies included were only available as preprints. We did not find any studies at low risk of bias for all quality domains and had concerns about applicability of results across all studies. We judged patient selection to be at high risk of bias in 50% of the studies because of deliberate over-sampling of samples with confirmed COVID-19 infection and unclear in seven out of 18 studies because of poor reporting. Sixteen (89%) studies used only a single, negative RT-PCR to confirm the absence of COVID-19 infection, risking missing infection. There was a lack of information on blinding of index test (n = 11), and around participant exclusions from analyses (n = 10). We did not observe differences in methodological quality between antigen and molecular test evaluations. Antigen tests Sensitivity varied considerably across studies (from 0% to 94%): the average sensitivity was 56.2% (95% CI 29.5 to 79.8%) and average specificity was 99.5% (95% CI 98.1% to 99.9%; based on 8 evaluations in 5 studies on 943 samples). Data for individual antigen tests were limited with no more than two studies for any test. Rapid molecular assays Sensitivity showed less variation compared to antigen tests (from 68% to 100%), average sensitivity was 95.2% (95% CI 86.7% to 98.3%) and specificity 98.9% (95% CI 97.3% to 99.5%) based on 13 evaluations in 11 studies of on 2255 samples. Predicted values based on a hypothetical cohort of 1000 people with suspected COVID-19 infection (with a prevalence of 10%) result in 105 positive test results including 10 false positives (positive predictive value 90%), and 895 negative results including 5 false negatives (negative predictive value 99%). Individual tests We calculated pooled results of individual tests for ID NOW (Abbott Laboratories) (5 evaluations) and Xpert Xpress (Cepheid Inc) (6 evaluations). Summary sensitivity for the Xpert Xpress assay (99.4%, 95% CI 98.0% to 99.8%) was 22.6 (95% CI 18.8 to 26.3) percentage points higher than that of ID NOW (76.8%, (95% CI 72.9% to 80.3%), whilst the specificity of Xpert Xpress (96.8%, 95% CI 90.6% to 99.0%) was marginally lower than ID NOW (99.6%, 95% CI 98.4% to 99.9%; a difference of -2.8% (95% CI -6.4 to 0.8)) AUTHORS' CONCLUSIONS: This review identifies early-stage evaluations of point-of-care tests for detecting SARS-CoV-2 infection, largely based on remnant laboratory samples. The findings currently have limited applicability, as we are uncertain whether tests will perform in the same way in clinical practice, and according to symptoms of COVID-19, duration of symptoms, or in asymptomatic people. Rapid tests have the potential to be used to inform triage of RT-PCR use, allowing earlier detection of those testing positive, but the evidence currently is not strong enough to determine how useful they are in clinical practice. Prospective and comparative evaluations of rapid tests for COVID-19 infection in clinically relevant settings are urgently needed. Studies should recruit consecutive series of eligible participants, including both those presenting for testing due to symptoms and asymptomatic people who may have come into contact with confirmed cases. Studies should clearly describe symptomatic status and document time from symptom onset or time since exposure. Point-of-care tests must be conducted on samples according to manufacturer instructions for use and be conducted at the point of care. Any future research study report should conform to the Standards for Reporting of Diagnostic Accuracy (STARD) guideline.


Assuntos
Betacoronavirus , Técnicas de Laboratório Clínico/métodos , Infecções por Coronavirus/diagnóstico , Pneumonia Viral/diagnóstico , Sistemas Automatizados de Assistência Junto ao Leito , Antígenos Virais/análise , Infecções por Coronavirus/epidemiologia , Reações Falso-Negativas , Reações Falso-Positivas , Humanos , Pandemias , Pneumonia Viral/epidemiologia , Sensibilidade e Especificidade
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