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1.
Clin Chem ; 68(1): 143-152, 2021 12 30.
Article in English | MEDLINE | ID: covidwho-20243230

ABSTRACT

BACKGROUND: The urgent need for massively scaled clinical testing for SARS-CoV-2, along with global shortages of critical reagents and supplies, has necessitated development of streamlined laboratory testing protocols. Conventional nucleic acid testing for SARS-CoV-2 involves collection of a clinical specimen with a nasopharyngeal swab in transport medium, nucleic acid extraction, and quantitative reverse-transcription PCR (RT-qPCR). As testing has scaled across the world, the global supply chain has buckled, rendering testing reagents and materials scarce. To address shortages, we developed SwabExpress, an end-to-end protocol developed to employ mass produced anterior nares swabs and bypass the requirement for transport media and nucleic acid extraction. METHODS: We evaluated anterior nares swabs, transported dry and eluted in low-TE buffer as a direct-to-RT-qPCR alternative to extraction-dependent viral transport media. We validated our protocol of using heat treatment for viral inactivation and added a proteinase K digestion step to reduce amplification interference. We tested this protocol across archived and prospectively collected swab specimens to fine-tune test performance. RESULTS: After optimization, SwabExpress has a low limit of detection at 2-4 molecules/µL, 100% sensitivity, and 99.4% specificity when compared side by side with a traditional RT-qPCR protocol employing extraction. On real-world specimens, SwabExpress outperforms an automated extraction system while simultaneously reducing cost and hands-on time. CONCLUSION: SwabExpress is a simplified workflow that facilitates scaled testing for COVID-19 without sacrificing test performance. It may serve as a template for the simplification of PCR-based clinical laboratory tests, particularly in times of critical shortages during pandemics.


Subject(s)
COVID-19 Nucleic Acid Testing/methods , COVID-19 , COVID-19/diagnosis , Clinical Laboratory Techniques , Humans , RNA, Viral/isolation & purification , Real-Time Polymerase Chain Reaction , SARS-CoV-2/isolation & purification , Sensitivity and Specificity , Specimen Handling
6.
Am J Clin Pathol ; 154(3): 425-426, 2020 08 05.
Article in English | MEDLINE | ID: covidwho-20236250
10.
Biosensors (Basel) ; 13(2)2023 Jan 30.
Article in English | MEDLINE | ID: covidwho-20240819

ABSTRACT

The COVID-19 pandemic revealed a pressing need for the development of sensitive and low-cost point-of-care sensors for disease diagnosis. The current standard of care for COVID-19 is quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). This method is sensitive, but takes time, effort, and requires specialized equipment and reagents to be performed correctly. This make it unsuitable for widespread, rapid testing and causes poor individual and policy decision-making. Rapid antigen tests (RATs) are a widely used alternative that provide results quickly but have low sensitivity and are prone to false negatives, particularly in cases with lower viral burden. Electrochemical sensors have shown much promise in filling this technology gap, and impedance spectroscopy specifically has exciting potential in rapid screening of COVID-19. Due to the data-rich nature of impedance measurements performed at different frequencies, this method lends itself to machine-leaning (ML) algorithms for further data processing. This review summarizes the current state of impedance spectroscopy-based point-of-care sensors for the detection of the SARS-CoV-2 virus. This article also suggests future directions to address the technology's current limitations to move forward in this current pandemic and prepare for future outbreaks.


Subject(s)
COVID-19 , Humans , SARS-CoV-2 , Pandemics , COVID-19 Testing , Clinical Laboratory Techniques/methods , Sensitivity and Specificity
11.
Biosensors (Basel) ; 13(2)2023 Jan 23.
Article in English | MEDLINE | ID: covidwho-20238646

ABSTRACT

Rapid and sensitive detection of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is essential for early diagnosis and effective treatment. Nucleic acid testing has been considered the gold standard method for the diagnosis of COVID-19 for its high sensitivity and specificity. However, the polymerase chain reaction (PCR)-based method in the central lab requires expensive equipment and well-trained personnel, which makes it difficult to be used in resource-limited settings. It highlights the need for a sensitive and simple assay that allows potential patients to detect SARS-CoV-2 by themselves. Here, we developed an electricity-free self-testing system based on reverse transcription loop-mediated isothermal amplification (RT-LAMP) that allows for rapid and accurate detection of SARS-CoV-2. Our system employs a heating bag as the heat source, and a 3D-printed box filled with phase change material (PCM) that successfully regulates the temperature for the RT-LAMP. The colorimetric method could be completed in 40 min and the results could be read out by the naked eye. A ratiometric measurement for exact readout was also incorporated to improve the detection accuracy of the system. This self-testing system is a promising tool for point-of-care testing (POCT) that enables rapid and sensitive diagnosis of SARS-CoV-2 in the real world and will improve the current COVID-19 screening efforts for control and mitigation of the pandemic.


Subject(s)
COVID-19 , Humans , SARS-CoV-2 , Self-Testing , COVID-19 Testing , Clinical Laboratory Techniques/methods , Sensitivity and Specificity , Molecular Diagnostic Techniques/methods , Nucleic Acid Amplification Techniques/methods
12.
Sci Rep ; 13(1): 8893, 2023 06 01.
Article in English | MEDLINE | ID: covidwho-20245029

ABSTRACT

It has been revealed that SARS-CoV-2 can be efficiently isolated from clinical specimens such as nasal/nasopharyngeal swabs or saliva in cultured cells. In this study, we examined the efficiency of viral isolation including SARS-CoV-2 mutant strains between nasal/nasopharyngeal swab or saliva specimens. Furthermore, we also examined the comparison of viral isolation rates by sample species using simulated specimens for COVID-19. As a result, it was found that the isolation efficiency of SARS-CoV-2 in the saliva specimens was significantly lower than that in the nasal/nasopharyngeal swab specimens. In order to determine which component of saliva is responsible for the lower isolation rate of saliva specimens, we tested the abilities of lactoferrin, amylase, cathelicidin, and mucin, which are considered to be abundant in saliva, to inhibit the infection of SARS-CoV-2 pseudotyped viruses (SARS-CoV-2pv). Lactoferrin and amylase were found to inhibit SARS-CoV-2pv infection. In conclusion, even if the same number of viral genome copies was detected by the real-time RT-PCR test, infection of SARS-CoV-2 present in saliva is thought to be inhibited by inhibitory factors such as lactoferrin and amylase, compared to nasal/nasopharyngeal swab specimens.


Subject(s)
COVID-19 , Humans , SARS-CoV-2 , Saliva , Lactoferrin , COVID-19 Testing , Clinical Laboratory Techniques , Nasopharynx , Cell Culture Techniques , Specimen Handling
13.
PLoS One ; 18(6): e0287107, 2023.
Article in English | MEDLINE | ID: covidwho-20242214

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of coronavirus disease 2019 (COVID-19). RT-PCR detection of viral RNA represents the gold standard method for diagnosis of COVID-19. However, multiple diagnostic tests are needed for acute disease diagnosis and assessing immunity during the COVID-19 outbreak. Here, we developed in-house anti-RBD IgG and IgA enzyme-linked immunosorbent assays (ELISAs) using a well-defined serum sample panel for screening and identification of human SARS-CoV-2 infection. We found that our in-house anti-SARS-CoV-2 IgG ELISA displayed a 93.5% sensitivity and 98.8% specificity whereas our in-house anti-SARS-CoV-2 IgA ELISA provided assay sensitivity and specificity at 89.5% and 99.4%, respectively. The agreement kappa values of our in-house anti-SARS-CoV-2 IgG and IgA ELISA assays were deemed to be excellent and fair, respectively, when compared to RT-PCR and excellent for both assays when compared to Euroimmun anti-SARS-CoV-2 IgG and IgA ELISAs. These data indicate that our in-house anti-SARS-CoV-2 IgG and IgA ELISAs are compatible performing assays for the detection of SARS-CoV-2 infection.


Subject(s)
COVID-19 , Humans , COVID-19/diagnosis , SARS-CoV-2 , COVID-19 Testing , Clinical Laboratory Techniques/methods , Enzyme-Linked Immunosorbent Assay/methods , Sensitivity and Specificity , Antibodies, Viral , Immunoglobulin G , Reference Standards , Immunoglobulin A , Immunoglobulin M
14.
Curr Opin Ophthalmol ; 31(6): 489-494, 2020 Nov.
Article in English | MEDLINE | ID: covidwho-2326684

ABSTRACT

PURPOSE OF REVIEW: To provide a summary of the neuro-ophthalmic manifestations of coronavirus disease 19 (COVID-19), documented in the literature thus far. RECENT FINDINGS: A small but growing literature documents cases of new onset neuro-ophthalmic disease, in the setting of COVID-19 infection. Patients with COVID-19 have experienced acute onset vision loss, optic neuritis, cranial neuropathies, and Miller Fisher syndrome. In addition, COVID-19 increases the risk of cerebrovascular diseases that can impact the visual system. SUMMARY: The literature on COVID-19 continues to evolve. Although COVID-19 primarily impacts the respiratory system, there are several reports of new onset neuro-ophthalmic conditions in COVID-infected patients. When patients present with new onset neuro-ophthalmic issues, COVID-19 should be kept on the differential. Testing for COVID-19 should be considered, especially when fever or respiratory symptoms are also present. When screening general patients for COVID-19-associated symptoms, frontline physicians can consider including questions about diplopia, eye pain, pain with extraocular movements, decreased vision, gait issues, and other neurologic symptoms. The presence of these symptoms may increase the overall probability of viral infection, especially when fever or respiratory symptoms are present. More research is needed to establish a causal relationship between COVID-19 and neuro-ophthalmic disease, and better understand pathogenesis.


Subject(s)
Betacoronavirus , Coronavirus Infections/complications , Pneumonia, Viral/complications , Animals , COVID-19 , COVID-19 Testing , Clinical Laboratory Techniques , Coronavirus Infections/diagnosis , Diplopia/etiology , Eye Pain/etiology , Humans , Optic Neuritis/etiology , Pandemics , Pneumonia, Viral/diagnosis , SARS-CoV-2
16.
Arch Microbiol ; 205(6): 239, 2023 May 17.
Article in English | MEDLINE | ID: covidwho-2322409

ABSTRACT

COVID-19 is a highly infectious disease caused by the SARS-CoV-2 virus, which primarily affects the respiratory system and can lead to severe illness. The virus is extremely contagious, early and accurate diagnosis of SARS-CoV-2 is crucial to contain its spread, to provide prompt treatment, and to prevent complications. Currently, the reverse transcriptase polymerase chain reaction (RT-PCR) is considered to be the gold standard for detecting COVID-19 in its early stages. In addition, loop-mediated isothermal amplification (LMAP), clustering rule interval short palindromic repeats (CRISPR), colloidal gold immunochromatographic assay (GICA), computed tomography (CT), and electrochemical sensors are also common tests. However, these different methods vary greatly in terms of their detection efficiency, specificity, accuracy, sensitivity, cost, and throughput. Besides, most of the current detection methods are conducted in central hospitals and laboratories, which is a great challenge for remote and underdeveloped areas. Therefore, it is essential to review the advantages and disadvantages of different COVID-19 detection methods, as well as the technology that can enhance detection efficiency and improve detection quality in greater details.


Subject(s)
COVID-19 Testing , COVID-19 , Humans , COVID-19/diagnosis , SARS-CoV-2/genetics , Clinical Laboratory Techniques/methods , Sensitivity and Specificity , Nucleic Acid Amplification Techniques/methods , Quality Control
17.
Euro Surveill ; 25(23)2020 06.
Article in English | MEDLINE | ID: covidwho-2313322

ABSTRACT

We reviewed the diagnostic accuracy of SARS-CoV-2 serological tests. Random-effects models yielded a summary sensitivity of 82% for IgM, and 85% for IgG and total antibodies. For specificity, the pooled estimate were 98% for IgM and 99% for IgG and total antibodies. In populations with ≤ 5% of seroconverted individuals, unless the assays have perfect (i.e. 100%) specificity, the positive predictive value would be ≤ 88%. Serological tests should be used for prevalence surveys only in hard-hit areas.


Subject(s)
Antibodies, Viral/blood , Clinical Laboratory Techniques/methods , Coronaviridae Infections/diagnosis , Coronavirus Infections/diagnosis , Coronavirus/immunology , Pneumonia, Viral/diagnosis , Serologic Tests/standards , Severe Acute Respiratory Syndrome/immunology , Betacoronavirus , COVID-19 , COVID-19 Testing , Clinical Laboratory Techniques/standards , Coronavirus/isolation & purification , Coronavirus Infections/epidemiology , Coronavirus Infections/immunology , Humans , Immunoglobulin G/blood , Immunoglobulin M/blood , Pandemics , Pneumonia, Viral/epidemiology , Pneumonia, Viral/immunology , Predictive Value of Tests , SARS-CoV-2 , Sensitivity and Specificity , Serologic Tests/methods , Severe Acute Respiratory Syndrome/blood
19.
Epidemiol Mikrobiol Imunol ; 72(1): 3-8, 2023.
Article in English | MEDLINE | ID: covidwho-2316000

ABSTRACT

OBJECTIVE: To determine the sensitivity and specificity of the Abbott ID-NOW™ test in the diagnosis of COVID-19. The test is based on the detection of the SARS-CoV-2 gene by isothermal amplification technology. METHODS: From 303 individuals, two nasopharyngeal swabs and one oropharyngeal swab were collected to be tested in parallel by the ID-NOW™ test and PCR test (Allplex™ SARS-CoV-2 Assay). A subgroup of 107 individuals presented to the public collection point for covid-19 at the Motol University Hospital during the dominance of the Delta variant, and the others were tested via the Adult Emergency Admission Department during the dominance of the Omicron variant. RESULTS: Of 297 valid samples, 43 were positive by the PCR assay and 33 were positive by the ID-NOW™ test (sensitivity 76.74%; 95% CI 61.37 to 88.24%). ID-NOW™ detected three samples as positive, but the positivity was not confirmed by PCR (specificity 98.82%; 95% CI 96.59 to 99.76%). A significant increase in sensitivity up to 100% is observed for samples with a higher viral load (with a PCR threshold cycle value below 30 or from patients with symptoms of COVID-19). The Delta or Omicron variant has no significant effect on the sensitivity of the test. CONCLUSION: Due to its ease of use and speed of result, ID-NOW™ is a suitable diagnostic tool for prompt assessment of a patient's infectivity. If, despite the negative ID-NOW™ result, the patient has symptoms of COVID-19, it is advised to perform a classic PCR test for SARS-CoV-2.


Subject(s)
COVID-19 , SARS-CoV-2 , Adult , Humans , SARS-CoV-2/genetics , COVID-19/diagnosis , COVID-19 Testing , Clinical Laboratory Techniques , Sensitivity and Specificity
20.
Clin Infect Dis ; 75(4): 723-728, 2022 Sep 10.
Article in English | MEDLINE | ID: covidwho-2315683

ABSTRACT

Testing programs for severe acute respiratory syndrome coronavirus 2 have relied on high-throughput polymerase chain reaction laboratory tests and rapid antigen assays to meet diagnostic needs. Both technologies are essential; however, issues of cost, accessibility, manufacturing delays, and performance have limited their use in low-resource settings and contributed to the global inequity in coronavirus disease 2019 testing. Emerging low-cost, multidisease point-of-care nucleic acid tests may address these limitations and strengthen pandemic preparedness, especially within primary healthcare where most cases of disease first present. Widespread deployment of these novel technologies will also help close long-standing test access gaps for other diseases, including tuberculosis, human immunodeficiency virus, cervical cancer, viral hepatitis, and sexually transmitted infections. We propose a more optimized testing framework based on greater use of point-of-care nucleic acid tests together with rapid immunologic assays and high-throughput laboratory molecular tests to improve the diagnosis of priority endemic and epidemic diseases, as well as strengthen the overall delivery of primary healthcare services.


Subject(s)
COVID-19 , Nucleic Acids , COVID-19/diagnosis , COVID-19 Testing , Clinical Laboratory Techniques , Humans , Point-of-Care Testing
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