Comparative performance study of three Ebola rapid diagnostic tests in Guinea

Abstract Background The 2014/15 Ebola outbreak in West Africa resulted in 11,000 deaths and massive strain on local health systems, and the ongoing outbreak in Democratic Republic of Congo has afflicted more than 3000 people. Accurate, rapid Ebola diagnostics suitable for field deployment would enable prompt identification and effective response to future outbreaks, yet remain largely unavailable. The purpose of this study was to assess the accuracy of three novel rapid diagnostic tests (RDTs): an Ebola, an Ebola-Malaria, and a Fever Panel test that includes Ebola, all from a single manufacturer. Methods We evaluated the three RDTs in 109 Ebola-positive and 96 Ebola-negative stored serum samples collected during the outbreak in Guinea in 2014/15, and tested by real-time polymerase chain reaction (RT-PCR). Sensitivity, specificity, and overall percent agreement were calculated for each RDT using RT-PCR as a reference standard, stratified by Ct value ranges. Results All tests performed with high accuracy on samples with low Ct value (high viral load). The Fever Panel test performed with the highest accuracy, with a sensitivity of 89.9% and specificity of 90.6%. The Ebola and Ebola-Malaria tests performed comparably to each other: sensitivity was 77.1 and 78% respectively, and specificity was 91.7% for the Ebola test and 95.8% for the Ebola-Malaria test. Conclusions This study evaluated the accuracy of three novel rapid diagnostic tests for Ebola. The tests may have significant public health relevance, particularly the Fever Panel test, which detects seven pathogens including Ebola. Given limitations to the study resulting from uncertain sample quality, further evaluation is warranted. All tests performed with highest accuracy on samples with low Ct value (high viral load), and the data presented here suggests that these RDTs may be useful for point-of-care diagnosis of cases in the context of an outbreak. Restrictions to their use in non-severe Ebola cases or for longitudinal monitoring, when viral loads are lower, may be appropriate. Highlighting the challenge in developing and evaluating Ebola RDTs, there were concerns regarding sample integrity and reference testing, and there is a need for additional research to validate these assays.

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Diagnostic accuracy of SARS-CoV-2 rapid antigen detection testing in symptomatic and asymptomatic children in the clinical setting

Journal of Clinical Microbiology ◽

10.1128/jcm.00991-21 ◽

2021 ◽

Author(s):

Arnaud G. L’Huillier ◽

Matthieu Lacour ◽

Debora Sadiku ◽

Mehdi A. Gadiri ◽

Loraine De Siebenthal ◽

...

Keyword(s):

Viral Load ◽

Diagnostic Accuracy ◽

Diagnostic Tests ◽

Diagnostic Performance ◽

Rapid Test ◽

Rapid Diagnostic Tests ◽

Rt Pcr ◽

Test Device ◽

Asymptomatic Children ◽

Post Onset

Background. Antigen-based rapid diagnostic tests (RDTs) are used in children despite the lack of data. We evaluated the diagnostic performance of the Panbio TM -COVID-19 Ag Rapid Test Device (P-RDT) in children. Methods. Symptomatic and asymptomatic participants 0-16yo had two NPS for both RT-PCR and P-RDT Results. 822 participants completed the study, of which 533 (64.9%) were symptomatic. Among the 119 (14.5%) RT-PCR-positive patients, the P-RDT sensitivity was 0.66 (95%CI 0.57-0.74). Mean viral load (VL) was higher among P-RDT-positive than negative ones (p<0.001). Sensitivity was 0.91 in specimens with VL>1.0E6 IU/mL (95%CI 0.83-0.99), and decreased to 0.75 (95%CI 0.66-0.83) for specimens >1.0E3 IU/mL. Among symptomatic participants, the P-RDT displayed a sensitivity of 0.73 (95%CI 0.64-0.82), which peaked at 1.00 at 2 days post-onset of symptoms (DPOS; 95%CI 1.00-1.00), then decreased to 0.56 (95%CI 0.23-0.88) at 5 DPOS. There was a trend towards lower P-RDT sensitivity in symptomatic children <12 years (0.62 [95%CI 0.45-0.78]) versus ≥12 years (0.80 [95%CI 0.69-0.91]; p=0.09). In asymptomatic participants, the P-RDT displayed a sensitivity of 0.43 (95%CI 0.26-0.61). Specificity was 1.00 in symptomatic and asymptomatic children (95%CI 0.99-1.00). Conclusion . The overall respective 73% and 43% sensitivities of P-RDT in symptomatic and asymptomatic children was below the 80% cut-off recommended by the WHO. We observed a correlation between VL and P-RDT sensitivity as well as variation of sensitivity according to DPOS, a major determinant of VL. These data highlight the limitations of RDTs in children, with the potential exception in early symptomatic children ≥12yrs.

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Viral Dynamics and Real-Time RT-PCR Ct Values Correlation with Disease Severity in COVID-19

Diagnostics ◽

10.3390/diagnostics11061091 ◽

2021 ◽

Vol 11 (6) ◽

pp. 1091

Author(s):

Ali A. Rabaan ◽

Raghavendra Tirupathi ◽

Anupam A Sule ◽

Jehad Aldali ◽

Abbas Al Mutair ◽

...

Keyword(s):

Viral Load ◽

Real Time ◽

Disease Severity ◽

False Negative ◽

Influential Factors ◽

Confirmatory Test ◽

Acid Extraction ◽

Rt Pcr ◽

Viral Kinetics ◽

Ct Value

Real-time RT-PCR is considered the gold standard confirmatory test for coronavirus disease 2019 (COVID-19). However, many scientists disagree, and it is essential to understand that several factors and variables can cause a false-negative test. In this context, cycle threshold (Ct) values are being utilized to diagnose or predict SARS-CoV-2 infection. This practice has a significant clinical utility as Ct values can be correlated with the viral load. In addition, Ct values have a strong correlation with multiple haematological and biochemical markers. However, it is essential to consider that Ct values might be affected by pre-analytic, analytic, and post-analytical variables such as collection technique, specimen type, sampling time, viral kinetics, transport and storage conditions, nucleic acid extraction, viral RNA load, primer designing, real-time PCR efficiency, and Ct value determination method. Therefore, understanding the interpretation of Ct values and other influential factors could play a crucial role in interpreting viral load and disease severity. In several clinical studies consisting of small or large sample sizes, several discrepancies exist regarding a significant positive correlation between the Ct value and disease severity in COVID-19. In this context, a revised review of the literature has been conducted to fill the knowledge gaps regarding the correlations between Ct values and severity/fatality rates of patients with COVID-19. Various databases such as PubMed, Science Direct, Medline, Scopus, and Google Scholar were searched up to April 2021 by using keywords including “RT-PCR or viral load”, “SARS-CoV-2 and RT-PCR”, “Ct value and viral load”, “Ct value or COVID-19”. Research articles were extracted and selected independently by the authors and included in the present review based on their relevance to the study. The current narrative review explores the correlation of Ct values with mortality, disease progression, severity, and infectivity. We also discuss the factors that can affect these values, such as collection technique, type of swab, sampling method, etc.

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Prolonged Detection of SARS CoV2 RNA in Extracellular Vesicles in Nasal Swab RT-PCR Negative Patients

10.1101/2021.12.16.21267912 ◽

2021 ◽

Author(s):

P Debishree Subudhi ◽

Sheetalnath Rooge ◽

Swati Thangriyal ◽

Reshu Aggarwal ◽

Ekta Gupta ◽

...

Keyword(s):

Endothelial Cells ◽

Viral Load ◽

Liver Disease ◽

Chronic Liver Disease ◽

Extracellular Vesicles ◽

Nasal Swab ◽

High Viral Load ◽

Chronic Liver ◽

Rt Pcr ◽

Route Of Transmission

Background: There is a prolonged RT PCR positivity seen in COVID-19 infected patients up to 2 to 3 months. It is assumed that this virus is usually non-infective but there are hardly any study on the reactivation of this virus within the respiratory tract. We aim to investigate the presence of viral particles inside Extracellular vesicles (EV) and its role in underlying liver disease patients. Methods: SARS CoV2 nasal and throat swab RT-PCR positive n=78 {n=24(66.6%) chronic liver disease (CLD); n=52 (81.3%) non liver disease} n=5 RT PCR negative subjects (HC) were studied. SARS CoV2 patients were also followed up for day (d) 7, 14 and 28. Nasal swab [collected in viral transport media (VTM)] and plasma samples were investigated at each time point. Extracellular vesicles were isolated using differential ultracentrifugation. SARS CoV2 RNA was measured using qRT-PCR by Altona Real Star kit. Cellular origin of EV was confirmed using epithelial cells (Epcam+ CK19+ CDh1+), endothelial cells (CD31+CD45-), and hepatocytes (ASGPR+) surface markers by Flow cytometry. Results: The COVID19 patients {Mean age 54±23 years; 41 males} were having severity between moderate to severe. In patients with cirrhosis, the most common aetiology of liver disease was alcohol (MELD 22±8). In baseline RT-PCR positive patients, SARS-CoV2 RNA inside the EV was present in 64/74 (82%) patients with comparable viral load between VTM and EV (mean 1/CT 0.033±0.005 vs. 1/CT 0.029±0.014, p=ns). On follow-up at day 7, of the 24 patients negative for COVID19, 10 (41%) had persistence of virus in the EV (1/CT 0.028±0.004) and on day 14, 14 of 40 (35%) negative RT-PCR had EVs with SARS CoV2 RNA (1/CT 0.028±0.06). The mean viral load decreased at day7 and day14 in nasal swab from baseline (p=0.001) but not in EV. SARS-CoV2 RNA otherwise undetectable in plasma, was found to be positive in EV in 12.5% of COVID19 positive patients. Interestingly, significantly prolonged and high viral load was found in EV at day 14 in CLD COVID19 patients compared to COVID19 alone (p=0.002). The high cellular injury was seen in CLD COVID19 infected patients with significant high levels of EV associated with endothelial cells and hepatocytes than COVID19 alone (p=0.004; 0.001). Conclusion: Identification of SARS-CoV2 RNA in EV, in RT-PCR negative patients indicates persistence of infection for and likely recurrence of the infection. It is suggestive of another route of transmission as EV harbour SARS CoV2 RNA. EV associated RNA may determine the ongoing inflammation and clinical course of subjects with undetectable SARS-CoV2 virus and this may also have relevance in management of chronic liver disease patients.

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Rapid Diagnosis of SARS-CoV-2 Pneumonia on Lower Respiratory Tract Specimens

10.21203/rs.3.rs-684790/v1 ◽

2021 ◽

Author(s):

Vanessa De Pace ◽

Patrizia Caligiuri ◽

Valentina Ricucci ◽

Nicola Nigro ◽

Barbara Galano ◽

...

Keyword(s):

Intensive Care ◽

Viral Load ◽

Respiratory Tract ◽

Intensive Care Units ◽

Lower Respiratory Tract ◽

Clinical Decision Making ◽

High Viral Load ◽

Rt Pcr ◽

Predictive Values ◽

Rapid Pcr

Abstract Background: The ongoing pandemic of SARS-CoV-2 requires the availability of accurate and rapid diagnostic tests, especially in some clinical settings like emergency and intensive care units. The objective of this study was to evaluate the diagnostic performances of rapid PCR kit Vivalytic SARS-CoV-2 in lower respiratory tract (LRT) specimens.Methods: A consecutive sample of LRT specimens (bronchoalveolar lavage and bronchoaspirates) was collected from Intensive Care Units of San Martino Hospital (Genoa, Italy) between November 2020 and January 2021. All samples were tested in RT-PCR by using Allplex™ SARS-CoV-2 assay (Seegene Inc., South Korea). Based on RT-PCR results, specimens were categorized into negative, positive with high viral load [cycle threshold (Ct) ≤30] and positive with low viral load (Ct of 31–35). A quota 1:1:1 sampling was used to achieve a sample size of 75. Then, all specimens were tested in the rapid PCR assay Vivalytic SARS-CoV-2 (Bosch Healthcare Solutions GmbH, Germany). The diagnostic performance of the rapid PCR against RT-PCR was assessed through calculation of accuracy, Cohen’s κ, sensitivity, specificity and expected positive (PPV) and negative (NPV) predictive values.Results: The overall diagnostic accuracy of the Vivalytic SARS-CoV-2 was 97.3% (95% CI: 90.9–99.3%) with an excellent Cohen’s κ of 0.94 (95% CI: 0.72–1). The sensitivity and specificity were 96% (95% CI: 86.5–98.9%) and 100% (95% CI: 86.7–100%), respectively. Samples with high viral loads had a sensitivity of 100% (Table 1). The distributions of E gene Ct values were similar (Wilcoxon’s test: P=0.070) with medians of 35 (IQR: 25–36) and 35 (IQR: 25–35), respectively (Figure 1). NPV and PPV was 92.6% and 100%, respectively.Conclusions: This study shows Vivalytic SARS-CoV-2 can be used following the sample liquefaction on LRT specimens. It’s a feasible and highly accurate molecular procedure especially in high viral load samples. This assay allows having a result in about 40 min and therefore may accelerate the clinical decision making in urgent/emergency situations.

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Detecting SARS-CoV-2 by Realtime RT-PCR in clinical samples collected in the North of Vietnam

Tạp chí Y học Dự phòng ◽

10.51403/0868-2836/2020/114 ◽

2021 ◽

Vol 30 (9) ◽

pp. 11-17

Author(s):

Hoang Vu Mai Phuong ◽

Ung Thi Hong Trang ◽

Nguyen Vu Son ◽

Le Thi Thanh ◽

Nguyen Le Khanh Hang ◽

...

Keyword(s):

Viral Load ◽

Average Rate ◽

Clinical Samples ◽

Viet Nam ◽

Rt Pcr ◽

Ct Value ◽

The North ◽

Viral Load Data ◽

The Mean ◽

High Level

From January to August 2020, Northern Viet Nam faced a COVID-19 outbreak, up to September 2020, there were 1122 confrmed cases of SARS-CoV-2, of which 465 cases were imported from Europe, America and Asia, 657 cases were identifed domestically. A total of 30,686 samples were collected during the SARS-CoV-2 outbreak in Northern Viet Nam and examined by Real-time RT-PCR using primers and probe from Charite - Berlin protocol. This study showed the initial results of SARS-CoV-2 detection and RNA quantitative in positive samples. The positive rate was 0.8%, ranging from 0.4 to 3.5% according to collection sites. Out of 251 positive samples, the mean Ct value was 28 (IQR: 22.3-32; range 14 - 38). The positive samples had a Ct value below 30 was 68.5%, there was no signifcant difference between the Ct value of the group ≤ 30 and > 30. The mean of the RNA copies/µl was 8.4.107, (IQR: 2.29.106 - 1.83.109 RNA copies/µl, range: 1.95.103 – 4.95.1011). In the group of imported COVID-19 cases, the rate of virus at low level was 29%, an average was 56% and at high level was 15%. In the community groups, the viral load data showed that the average rate at low, intermediate and high level were 20%, 63% and 17% respectively. The proportion of high-level viral load may raise an alert to start the quarantine process to reduce the transmission of SARS-CoV-2

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Diagnostic accuracy of two commercial SARS-CoV-2 Antigen-detecting rapid tests at the point of care in community-based testing centers

10.1101/2020.11.20.20235341 ◽

2020 ◽

Cited By ~ 4

Author(s):

Alice Berger ◽

Marie Therese Ngo Nsoga ◽

Francisco Javier Perez-Rodriguez ◽

Yasmine Abi Aad ◽

Pascale Sattonnet-Roche ◽

...

Keyword(s):

Diagnostic Tests ◽

Point Of Care ◽

Rapid Test ◽

Diagnostic Value ◽

Rapid Diagnostic Tests ◽

Ease Of Use ◽

Rt Pcr ◽

Test Device ◽

Community Based ◽

Rapid Tests

AbstractBackgroundAntigen-detecting rapid diagnostic tests for SARS-CoV-2 offer new opportunities for the quick and laboratory-independent identification of infected individuals for control of the SARS-CoV-2 pandemic.MethodsWe performed a prospective, single-center, point of care validation of two antigen-detecting rapid diagnostic tests (Ag-RDT) in comparison to RT-PCR on nasopharyngeal swabs.FindingsBetween October 9th and 23rd, 2020, 1064 participants were enrolled. The Panbio™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%.InterpretationWe 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.FundingFoundation of Innovative Diagnostics (FIND), Fondation privée des HUG, Pictet Charitable Foundation.

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LABORATORY METHODS AND PREVALENCE OF SARS-COV-2 INFECTIONS IN THE 2ND SEMESTER OF 2021 IN THE EMERGENCY CLINICAL COUNTY HOSPITAL OF CONSTANTA

10.32008/geolinks2021/b1/v3/11 ◽

2021 ◽

Author(s):

Stoicescu Ramona ◽

Stoicescu Razvan-Alexandru ◽

Codrin Gheorghe ◽

Schroder Verginica

Keyword(s):

Respiratory Tract ◽

Diagnostic Tests ◽

Rapid Diagnostic Tests ◽

Antigen Detection ◽

Nucleic Acid Amplification ◽

Rt Pcr ◽

Laboratory Methods ◽

Rapid Tests ◽

Polymerase Chain ◽

Tract Infections

"Diagnosing infections with SARS-CoV-2 is still of great interest due to the health and economic impact of COVID pandemic. The 4th wave of the COVID-19 pandemic is expected and is considered to be stronger and faster due to the dominance of Delta variant which is highly contagious [1]. SARS-CoV-2 also known as 2019-nCoV is one of the three coronaviruses (together with SARS-CoV or SARS-CoV1/Severe acute respiratory syndrome coronavirus), MERS-CoV /Middle East Respiratory Syndrome coronavirus) which can cause severe respiratory tract infections in humans [2]. Early diagnosis in COVID 19 infection is the key for preventing infection transmission in collectivity and proper medical care for the ill patients. Gold standard for diagnosing SARS-Co-V-2 infection according to WHO recommendation is using nucleic acid amplification tests (NAAT)/ reverse transcription polymerase chain reaction (RT-PCR). The search is on to develop reliable but less expensive and faster diagnostic tests that detect antigens specific for SARS-CoV-2 infection. Antigen-detection diagnostic tests are designed to directly detect SARSCoV-2 proteins produced by replicating virus in respiratory secretions so-called rapid diagnostic tests, or RDTs. The diagnostic development landscape is dynamic, with nearly a hundred companies developing or manufacturing rapid tests for SARS-CoV-2 antigen detection [3]. In the last 3 months our hospital introduced the antigen test or Rapid diagnostic tests (RDT) which detects the presence of viral proteins (antigens) expressed by the COVID-19 virus in a sample from the respiratory tract of a person. All RDT were confirmed next day with a RT-PCR. The number of positive cases detected during 3 months in our laboratory was 425. There were 326 positive tests in April, 106 positive tests in May and 7 positive tests in June. Compared with the number of positive tests in the 1st semester of 2021, the positive tests have significantly declined."

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A CYCLE THRESHOLD VALUE-BASED EPIDEMIC PROGNOSTICATION TO MONITOR LONG-TERM EPIDEMIOLOGIC TRENDS OF SARS-COV-2 VIRUS

10.36106/gjra/8200797 ◽

2021 ◽

pp. 24-30

Author(s):

Aditi Munmun Sengupta ◽

Diptendu Chatterjee ◽

Bibhuti Saha

Keyword(s):

Meta Analysis ◽

Threshold Value ◽

High Viral Load ◽

World Health ◽

Rt Pcr ◽

Cycle Threshold ◽

Ct Value ◽

Health Organization ◽

The Impact

The real-time reverse transcription-polymerase chain reaction (RT-PCR) is considered as the sensitive proof for detecting the viral infection of the SARS-CoV-2 virus obtained from respiratory samples. The quantitative values for the analysis are benecial for estimating the transmissibility of people who test positive for SARS-CoV-2. This can be further achieved by analyzing the samples by semiquantitative means through the interpretation of the cycle threshold (Ct) values of RT-PCR that represent the rst cycle of PCR at which a detectable signal appears during the assays. The Ct value shows a correlation between high viral load and disease infectiousness, which is observed with other respiratory viruses, including the inuenza B infection and rhinovirus infection. Hence, the present study aims to analyze the surveillance of COVID-19 to monitor longer-term epidemiologic trends and trends in deaths due to COVID-19. In order to achieve this aim, the present review was reported to the preferred reporting items for systematic reviews and meta-analysis statements (PRISMA) for analyzing the Ct value-based epidemic predictions and to monitor long-term epidemiologic trends of SARS-CoV-2 virus. Total 33 studies have been nalized for nding out the results of the study. The epidemiologic parameter and a representative of the surveillance data for reporting to the World Health Organization were fullled by analyzing the systematic review and metaanalysis of the selected study. Moreover, the evaluation of the impact of the pandemic on the health care system and society was achieved by analyzing the studies mentioned here.

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Point-of-Care Diagnostic Tests for Detecting SARS-CoV-2 Antibodies: A Systematic Review and Meta-Analysis of Real-World Data

Journal of Clinical Medicine ◽

10.3390/jcm9051515 ◽

2020 ◽

Vol 9 (5) ◽

pp. 1515 ◽

Cited By ~ 17

Author(s):

Matteo Riccò ◽

Pietro Ferraro ◽

Giovanni Gualerzi ◽

Silvia Ranzieri ◽

Brandon Michael Henry ◽

...

Keyword(s):

Systematic Review ◽

Diagnostic Tests ◽

Large Scale ◽

Point Of Care ◽

Meta Analysis ◽

Rapid Diagnostic Tests ◽

Diagnostic Methods ◽

Rt Pcr ◽

Real World Data ◽

Healthcare Facilities

SARS-CoV-2 is responsible for a highly contagious infection, known as COVID-19. SARS-CoV-2 was discovered in late December 2019 and, since then, has become a global pandemic. Timely and accurate COVID-19 laboratory testing is an essential step in the management of the COVID-19 outbreak. To date, assays based on the reverse-transcription polymerase chain reaction (RT-PCR) in respiratory samples are the gold standard for COVID-19 diagnosis. Unfortunately, RT-PCR has several practical limitations. Consequently, alternative diagnostic methods are urgently required, both for alleviating the pressure on laboratories and healthcare facilities and for expanding testing capacity to enable large-scale screening and ensure a timely therapeutic intervention. To date, few studies have been conducted concerning the potential utilization of rapid testing for COVID-19, with some conflicting results. Therefore, the present systematic review and meta-analysis was undertaken to explore the feasibility of rapid diagnostic tests in the management of the COVID-19 outbreak. Based on ten studies, we computed a pooled sensitivity of 64.8% (95%CI 54.5–74.0), and specificity of 98.0% (95%CI 95.8–99.0), with high heterogeneity and risk of reporting bias. We can conclude that: (1) rapid diagnostic tests for COVID-19 are necessary, but should be adequately sensitive and specific; (2) few studies have been carried out to date; (3) the studies included are characterized by low numbers and low sample power, and (4) in light of these results, the use of available tests is currently questionable for clinical purposes and cannot substitute other more reliable molecular tests, such as assays based on RT-PCR.

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PREDICTIVE VALUE OF SMELL AND TASTE TEST VS PCR-RT SARS-COV-2 AND RAPID DIAGNOSTIC TESTS IN THE DIAGNOSIS OF INFECTION BY COVID-19. A PROSPECTIVE MULTI-CENTRIC STUDY.

10.1101/2020.08.31.20185298 ◽

2020 ◽

Author(s):

Rosalinda Pieruzzini ◽

Carlos Ayala ◽

Jose Navas ◽

Wilneg Carolina Rodriguez ◽

Nathalia Parra ◽

...

Keyword(s):

Predictive Value ◽

Diagnostic Tests ◽

Rapid Diagnostic Tests ◽

Variable Degree ◽

Rt Pcr ◽

Taste Test ◽

Taste Disorders ◽

Coronavirus Infection ◽

Diagnosis Of Infection

There is a relationship between smell and taste disturbances and coronavirus infection. These symptoms have been considered the best predictor of coronavirus infection, for this reason, it was decided to evaluate the predictive value of the smell and taste test and its association with the results of SARS-CoV-2 PCR-RT and rapid diagnostic tests. in the diagnosis of pathology. Methodology: 248 patients divided into 3 groups: asymptomatic, symptomatic without chemosensory disorders, and chemosensory disorders alone. All of them underwent SARS-CoV-2 PCR-RT, a rapid diagnostic test and a test of Venezuelan smell and basic taste at the beginning. Weekly follow-up with smell and taste test and SARS-CoV-2 PCR-RT until recovery. Results: 20.56% of patients had smell and taste disorders to a variable degree and were positive by SARS-CoV-PCR-RT. 2.15.3% of patients with chemosensory disorders were negative for COVID-19. The positive predictive value of the smell and taste test was 57.3; Sensitivity 41.13% and specificity 69.35%. There were no statistically significant differences by age, sex and chemosensory disorders. The predominant chemosensory disorder was the combination of mild hyposmia and hypogeusia and appeared in the company of other symptoms. Recovery occurred in an average of 8.5 days, asynchronously with the SARS-CoV-2 RT-PCR negativization, which occurred up to more than 15 days after the senses recovered. Maximum time of negativization of the RT-PCR of 34 days. Conclusion: chemosensory disorders are a symptom and / or sign of coronavirus disease but cannot be considered as predictors of said disease in this population studied. The gold standard remains the SARS-CoV-2 PCR-RT test. Rapid diagnostic tests should be used for follow-up. Recommendations: it is necessary to expand the sample, include routine psychophysical smell and taste tests to screen cases and take race and virus mutations into consideration to explain behavior in certain populations. Key words: Smell, taste, coronavirus, test, diagnosis.

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