scholarly journals Pooled Saliva Specimens for SARS-CoV-2 Testing

2020 ◽  
Author(s):  
Bidisha Barat ◽  
Sanchita Das ◽  
Valeria De Giorgi ◽  
David K. Henderson ◽  
Stacy Kopka ◽  
...  
Keyword(s):  
Viral Load ◽  
Screening Program ◽  
High Viral Load ◽  
Load Cycle ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
Lower Viral Load ◽  
Viral Loads ◽  
Viral Transport ◽  
Positive Specimen

AbstractWe evaluated saliva (SAL) specimens for SARS-CoV-2 RT-PCR testing by comparison of 459 prospectively paired nasopharyngeal (NP) or mid-turbinate (MT) swabs from 449 individuals with the aim of using saliva for asymptomatic screening. Samples were collected in a drive-through car line for symptomatic individuals (N=380) and in the emergency department (ED) (N=69). The percent positive and negative agreement of saliva compared to nasopharyngeal swab were 81.1% (95% CI: 65.8% – 90.5%) and 99.8% (95% CI: 98.7% – 100%), respectively. The sensitivity increased to 90.0% (95% CI: 74.4% – 96.5%) when considering only samples with moderate to high viral load (Cycle threshold (Ct) for the NP <=34). Pools of five saliva specimens were also evaluated on three platforms: bioMérieux NucliSENS easyMAG with ABI 7500Fast (CDC assay), Hologic Panther Fusion, and Roche COBAS 6800. The median loss of signal upon pooling was 2-4 Ct values across the platforms. The sensitivity of detecting a positive specimen in a pool compared with testing individually was 100%, 93%, and 95% for CDC 2019-nCoV Real-Time RT-PCR, Panther Fusion® SARS-CoV-2 assay, and cobas® SARS-CoV-2 test respectively, with decreased sample detection trending with lower viral load. We conclude that although pooled saliva testing, as collected in this study, is not quite as sensitive as NP/MT testing, saliva testing is adequate to detect individuals with higher viral loads in an asymptomatic screening program, does not require swabs or viral transport media for collection, and may help to improve voluntary screening compliance for those individuals averse to various forms of nasal collections.

scholarly journals Pooled Saliva Specimens for SARS-CoV-2 Testing

2020 ◽  
Author(s):  
Bidisha Barat ◽  
Sanchita Das ◽  
Valeria De Giorgi ◽  
David K. Henderson ◽  
Stacy Kopka ◽  
...  
Keyword(s):  
Viral Load ◽  
Screening Program ◽  
High Viral Load ◽  
Load Cycle ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
Viral Loads ◽  
Viral Transport ◽  
Average Loss ◽  
Positive Agreement

We evaluated saliva (SAL) specimens for SARS-CoV-2 RT-PCR testing by comparison of 459 prospectively paired nasopharyngeal (NP) or mid-turbinate (MT) swabs from 449 individuals with the aim of using saliva for asymptomatic screening. Samples were collected in a drive-through car line for symptomatic individuals (N=380) and in the emergency department (ED) (N=69). The percent positive and negative agreement of saliva compared to nasopharyngeal swab were 81.1% (95% CI: 65.8% – 90.5%) and 99.8% (95% CI: 98.7% – 100%), respectively. The percent positive agreement increased to 90.0% (95% CI: 74.4% – 96.5%) when considering only samples with moderate to high viral load (Cycle threshold (Ct) for the NP <=34). Pools of five saliva specimens were also evaluated on three platforms: bioMérieux NucliSENS easyMAG with ABI 7500Fast (CDC assay), Hologic Panther Fusion®, and Roche COBAS® 6800. The average loss of signal upon pooling was 2-3 Ct values across the platforms. The sensitivity of detecting a positive specimen in a pool compared with testing individually was 94%, 90%, and 94% for CDC 2019-nCoV Real-Time RT-PCR, Panther Fusion® SARS-CoV-2 assay, and cobas® SARS-CoV-2 test respectively, with decreased sample detection trending with lower viral load. We conclude that although pooled saliva testing, as collected in this study, is not quite as sensitive as NP/MT testing, saliva testing is adequate to detect individuals with higher viral loads in an asymptomatic screening program, does not require swabs or viral transport media for collection, and may help to improve voluntary screening compliance for those individuals averse to various forms of nasal collections.

scholarly journals Rapid diagnosis of SARS-CoV-2 pneumonia on lower respiratory tract specimens

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Vanessa De Pace ◽  
Patrizia Caligiuri ◽  
Valentina Ricucci ◽  
Nicola Nigro ◽  
Barbara Galano ◽  
...  
Keyword(s):  
Intensive Care ◽  
Viral Load ◽  
Lower Respiratory Tract ◽  
Diagnostic Performance ◽  
High Viral Load ◽  
Load Cycle ◽  
Rt Pcr ◽  
Cycle Threshold ◽  
Viral Loads ◽  
Rapid Pcr

Abstract Background The ongoing SARS-CoV-2 pandemic requires the availability of accurate and rapid diagnostic tests, especially in such clinical settings as emergency and intensive care units. The objective of this study was to evaluate the diagnostic performance of the Vivalytic SARS-CoV-2 rapid PCR kit in lower respiratory tract (LRT) specimens. Methods Consecutive LRT specimens (bronchoalveolar lavage and bronchoaspirates) were collected from Intensive Care Units of San Martino Hospital (Genoa, Italy) between November 2020 and January 2021. All samples underwent RT-PCR testing by means of the Allplex™ SARS-CoV-2 assay (Seegene Inc., South Korea). On the basis of RT-PCR results, specimens were categorized as negative, positive with high viral load [cycle threshold (Ct) ≤ 30] and positive with low viral load (Ct of 31–35). A 1:1:1 ratio was used to achieve a sample size of 75. All specimens were subsequently tested by means of the Vivalytic SARS-CoV-2 rapid PCR assay (Bosch Healthcare Solutions GmbH, Germany). The diagnostic performance of this assay was assessed against RT-PCR through the 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). Sensitivity and specificity were 96% (95% CI: 86.5–98.9%) and 100% (95% CI: 86.7–100%), respectively. In samples with high viral loads, sensitivity was 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) on Vivalytic and RT-PCR, respectively (Fig. 1). NPV and PPV was 92.6% and 100%, respectively.Table 1 Demographic characteristics and data sample type of the study cases (N = 75) Male, N (%) 56 (74.6%) Age (yr), Median (IQR) 65 (31–81) BAS, N (%) 43 (57.3%)  Negative 30.2%  Positive—High viral load [Ct ≤ 30] 27.9%  Positive—Low viral load [Ct 31–35] 41.9% BAL, N (%) 32 (42.7%)  Negative 37.5%  Positive—High viral load [Ct ≤ 30] 40.6%  Positive—Low viral load [Ct 31–35] 21.9% Data were expressed as proportions for categorical variables. Specimens were categorized into negative, positive with high viral load [cycle threshold (Ct) ≤ 30] and positive with low viral load (Ct of 31–35). BAS bronchoaspirates, BAL bronchoalveolar lavage, Ct cycle threshold Conclusions Vivalytic SARS-CoV-2 can be used effectively on LRT specimens following sample liquefaction. It is a feasible and highly accurate molecular procedure, especially in samples with high viral loads. This assay yields results in about 40 min, and may therefore accelerate clinical decision-making in urgent/emergency situations.

scholarly journals A Direct Comparison of Enhanced Saliva to Nasopharyngeal Swab for the Detection of SARS-CoV-2 in Symptomatic Patients

2020 ◽  
Vol 58 (11) ◽  
Author(s):  
Gary W. Procop ◽  
Nabin K. Shrestha ◽  
Sherilynn Vogel ◽  
Kelly Van Sickle ◽  
Susan Harrington ◽  
...  
Keyword(s):  
Viral Load ◽  
Final Analysis ◽  
Nasopharyngeal Swab ◽  
Reference Standard ◽  
Rt Pcr ◽  
Viral Transport ◽  
Qualitative Detection ◽  
Diagnostic Panel ◽  
The One ◽  
Positive Agreement

ABSTRACT The ongoing coronavirus disease 2019 (COVID-19) pandemic has resulted in shortages of nasopharyngeal swabs (NPS) and viral transport media, necessitating the search for alternate diagnostic specimens, such as saliva. We directly compared matched saliva and NPS specimens from symptomatic patients suspected of having COVID-19. An enhanced saliva specimen (i.e., strong sniff, elicited cough, and collection of saliva/secretions) was collected without transport medium prior to collection of NPS from 224 patients with symptoms deemed consistent with COVID-19. Both specimens were tested with the CDC 2019 nCoV real-time RT-PCR diagnostic panel (4 February 2020 version), with the NPS result used as the reference standard. For the 216 patients included in the final analysis, there was 100% positive agreement (38/38 positive specimens) and 99.4% negative agreement (177/178 negative specimens). The one discrepant specimen had the presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) confirmed in the saliva specimen using an alternate FDA EUA assay. The overall mean difference in cycle threshold (CT) values for the positive NPS and saliva specimens was −3.61 (95% confidence interval [CI], −5.78 to −1.44; P = 0.002). An enhanced saliva specimen performed as well as NPS for the qualitative detection of SARS-CoV-2 in symptomatic patients, although the overall mean viral load in saliva was lower.

scholarly journals Viral load and antibody levels in patients with COVID-19

2021 ◽  
Vol 8 (3) ◽  
pp. 010-018
Author(s):  
Iva Christova ◽  
Iva Trifonova ◽  
Teodora Gladnishka ◽  
Elena Dragusheva ◽  
Georgi Popov ◽  
...  
Keyword(s):  
Viral Load ◽  
High Viral Load ◽  
Igg Antibodies ◽  
Rt Pcr ◽  
Serum Samples ◽  
Weekly Basis ◽  
Specific Antibody Response ◽  
Viral Loads ◽  
Antibody Levels ◽  
Kinetics Of

Relations between viral load, antibody levels and COVID-19 severity are not well studied and results from such investigations are controversial. In this study, we investigated kinetics of viral load and antibody responses to SARS-CoV-2 in 20 patients with COVID-19 and analysed the association with disease severity. The patients were followed on weekly basis within the first month after the onset and then once per month for the next 4 months. Serum samples were tested for IgA, IgM, and IgG antibodies against SARS-CoV-2 using ELISA tests. SARS-CoV-2 viral load in nasopharyngeal swabs was measured by quantitative Realtime RT-PCR. For vast majority of the patients, the viral loads were at their highest levels at presentation and then declined gradually. Despite development of specific antibody response 7-11 days after the onset of COVID-19, SARS-CoV-2 RNA was still detected in nasopharyngeal swabs of most of the patients. There was no direct link between viral load and severity of COVID-19: some of mild and some of severe cases started with a high viral load. There was a relationship between the time from the onset of the disease and the viral load: the highest viral load was in the first days. In more severe cases, there was a tendency for slower reduction in viral load and longer detection of SARS-CoV-2 virus. Levels of the specific antibodies increased earlier and to higher levels and were present for longer time in patients with more severe manifestations of COVID-19 than in those with milder disease.

scholarly journals SARS-CoV-2 Viral Load Is Correlated With the Disease Severity and Mortality in Patients With Cancer

2021 ◽  
Vol 11 ◽  
Author(s):  
Maha Al-Mozaini ◽  
Abu Shadat M. Noman ◽  
Jawaher Alotaibi ◽  
Mohammed Rezaul Karim ◽  
A. S. M. Zahed ◽  
...  
Keyword(s):  
Viral Load ◽  
Cancer Patients ◽  
Disease Severity ◽  
High Viral Load ◽  
Attributable Mortality ◽  
Nasopharyngeal Swab ◽  
Viral Loads ◽  
Hematologic Cancer ◽  
Increased Risk ◽  
Anticancer Treatment

The correlation between severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) viral load and risk of disease severity in cancer patients is poorly understood. Given the fact that cancer patients are at increased risk of severe coronavirus disease 2019 (COVID-19), analysis of viral load and disease outcome in COVID-19-infected cancer patients is needed. Here, we measured the SARS-CoV-2 viral load using qPCR cycle threshold (Ct) values collected from 120 noncancer and 64 cancer patients’ nasopharyngeal swab samples who are admitted to hospitals. Our results showed that the in-hospital mortality for high viral load cancer patients was 41.38%, 23.81% for medium viral load and 14.29% for low viral load patients (p &lt; −0.01). On the other hand, the mortality rate for noncancer patients was lower: 22.22% among patients with high viral load, 5.13% among patients with medium viral load, and 1.85% among patients with low viral load (p &lt; 0.05). In addition, patients with lung and hematologic cancer showed higher possibilities of severe events in proportion to high viral load. Higher attributable mortality and severity were directly proportional to high viral load particularly in patients who are receiving anticancer treatment. Importantly, we found that the incubation period and serial interval time is shorter in cancer patients compared with noncancer cases. Our report suggests that high SARS-CoV-2 viral loads may play a significant role in the overall mortality and severity of COVID-19-positive cancer patients, and this warrants further study to explore the disease pathogenesis and their use as prognostic tools.

scholarly journals Impact of Severe Acute Respiratory Syndrome Coronavirus 2 Viral Load on Risk of Intubation and Mortality Among Hospitalized Patients With Coronavirus Disease 2019

2020 ◽  
Author(s):  
Reed Magleby ◽  
Lars F Westblade ◽  
Alex Trzebucki ◽  
Matthew S Simon ◽  
Mangala Rajan ◽  
...  
Keyword(s):  
New York ◽  
Viral Load ◽  
Severe Acute Respiratory Syndrome ◽  
Hospital Mortality ◽  
Smoking Status ◽  
High Viral Load ◽  
Hospitalized Patients ◽  
Nasopharyngeal Swab ◽  
Viral Loads ◽  
The Impact

Abstract Background Patients hospitalized with coronavirus disease 2019 (COVID-19) frequently require mechanical ventilation and have high mortality rates. However, the impact of viral burden on these outcomes is unknown. Methods We conducted a retrospective cohort study of patients hospitalized with COVID-19 from 30 March 2020 to 30 April 2020 at 2 hospitals in New York City. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral load was assessed using cycle threshold (Ct) values from a reverse transcription-polymerase chain reaction assay applied to nasopharyngeal swab samples. We compared characteristics and outcomes of patients with high, medium, and low admission viral loads and assessed whether viral load was independently associated with intubation and in-hospital mortality. Results We evaluated 678 patients with COVID-19. Higher viral load was associated with increased age, comorbidities, smoking status, and recent chemotherapy. In-hospital mortality was 35.0% (Ct &lt;25; n = 220), 17.6% (Ct 25–30; n = 216), and 6.2% (Ct &gt;30; n = 242) with high, medium, and low viral loads, respectively (P &lt; .001). The risk of intubation was also higher in patients with a high viral load (29.1%) compared with those with a medium (20.8%) or low viral load (14.9%; P &lt; .001). High viral load was independently associated with mortality (adjusted odds ratio [aOR], 6.05; 95% confidence interval [CI], 2.92–12.52) and intubation (aOR, 2.73; 95% CI, 1.68–4.44). Conclusions Admission SARS-CoV-2 viral load among hospitalized patients with COVID-19 independently correlates with the risk of intubation and in-hospital mortality. Providing this information to clinicians could potentially be used to guide patient care.

scholarly journals Comparing The Viral Load of Severe Acute Respiratory Syndrome Coronavirus 2 in Different Human Specimens

2020 ◽  
pp. 131-145
Author(s):  
Ali Hattem Hussain
Keyword(s):  
Viral Load ◽  
Rectal Swab ◽  
Throat Swab ◽  
Meta Analysis ◽  
Threshold Value ◽  
Load Cycle ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
Load Detection ◽  
Respiratory Specimens

This meta-analysis study analyzed the data of 47 recent studies with data related SARS-COV-2 viral load detection in different human specimens. 1099 patients were tested for SARS-COV-2 viral load using up to 19 different respiratory and non-respiratory specimens using RT-PCR by targeting different types of viral genes of which ORF1ab is the most commonly used target gene. 9909 specimens were taken from the patients. The mean of viral load cycle threshold value is 17.8 (±11.7), with a median of 15.95 with minimum value of 0.2 and a maximum value of 36.5. Nasopharyngeal swab has the highest positivity rate (90.5%) for viral load detection followed by Bronchoalveolar lavage, nasal swab, nasopharyngeal aspirate, throat swab and sputum. For the non-respiratory specimen, stool and rectal swab are most appropriate specimens followed by blood. The urine is not appropriate specimen for viral load detection due to very low sensitivity. The sputum was positive up to 23 days in a daily manner since start of symptoms except for the days 19, 21, and 23 that were negative for the virus. Three specimens, the nasopharyngeal swab, throat swab, and rectal swab, showed positive RT-PCR results before the appearance of COVID-19 clinical features.  Possible positive results can be present up to 43 days in throat swab, stool, and rectal swab. After negative conversion of respiratory specimens, the viral shedding can continue more than one month from stool and rectal swab. The 3rd day since onset of symptoms is the most day of testing (223/2935). The highest positivity of SARS-COV-2 viral load was recorded in day 16 since the onset of symptoms.              

Detection of SARs CoV-2 during initial phase of pandemic from population of banas kantha district of Gujarat-India with special emphasis on pooled samples

2021 ◽  
Vol 7 (4) ◽  
pp. 295-299
Author(s):  
Hiren Patel ◽  
Parijat N Goswami
Keyword(s):  
Viral Load ◽  
Age Groups ◽  
High Viral Load ◽  
Rt Pcr ◽  
Viral Loads ◽  
Corona Virus ◽  
Asymptomatic Patients ◽  
Care Workers ◽  
Pcr Method ◽  
Pharynx Swab

Corona virus (SARs CoV-2) has caused immense effect on morbidity and mortality of the population globally. We undertook this study as we are a part of one of the network laboratories of ICMR to test the patient’s sample by RT PCR for the ORF 1 ab gene of corona virus. : For a period of one and half months (14 April to 31 May 2020) we tested the nasopharynx and oro-pharynx swab samples sent to us in VTM from the assigned districts of Gujarat. All the samples were subjected to RT PCR method by following standard methods. Total of 9.04%(256/2833) population was positive and 4.73%(139/2833) belonged to age groups 21-40 and 2.33% (66/2833) to 41-60yrs. Above the age of 60yrs there were only 0.95% (22/2833) cases which were positive. It was advantageous to pool the samples. Out of the number of pools prepared, we reported around 80% negative and rest were positive in pools. The study also included association of viral load and infectivity. We found that 12% of the asymptomatic people and 5.1% of symptomatic individuals had high viral load. : It is seen that the incidence of Novel corona virus -19 detection by RT PCR is a reliable method and the establishment of the Ct value and infectivity of the patient to the health care workers and relatives needs to be taken care of. Also, the study presents asymptomatic patients having high viral loads being highly infective.

Effective optimization of SARS-CoV-2 laboratory testing variables in an era of supply chain constraints

2020 ◽  
Vol 15 (15) ◽  
pp. 1483-1487
Author(s):  
Nikhil S Sahajpal ◽  
Ashis K Mondal ◽  
Allan Njau ◽  
Sudha Ananth ◽  
Kimya Jones ◽  
...  
Keyword(s):  
Supply Chain ◽  
Rna Extraction ◽  
Nasopharyngeal Swab ◽  
Sample Collection ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Short Supply ◽  
Viral Transport ◽  
3D Printed ◽  
Bridging Studies

RT-PCR-based assays for the detection of SARS-CoV-2 have played an essential role in the current COVID-19 pandemic. However, the sample collection and test reagents are in short supply, primarily due to supply chain issues. Thus, to eliminate testing constraints, we have optimized three key process variables: RNA extraction and RT-PCR reactions, different sample types and media to facilitate SARS-CoV-2 testing. By performing various validation and bridging studies, we have shown that various sample types such as nasopharyngeal swab, bronchioalveolar lavage and saliva, collected using conventional nasopharyngeal swabs, ESwab or 3D-printed swabs and, preserved in viral transport media, universal transport media, 0.9% sodium chloride or Amies media are compatible with RT-PCR assay for COVID-19. Besides, the reduction of PCR reagents by up to fourfold also produces reliable results.

scholarly journals Performance of Self-Collected Saliva Testing Compared with Nasopharyngeal Swab Testing for the Detection of SARS-CoV-2

Viruses ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 895
Author(s):  
Florence Carrouel ◽  
Martine Valette ◽  
Hervé Perrier ◽  
Maude Bouscambert-Duchamp ◽  
Claude Dussart ◽  
...  
Keyword(s):  
Viral Load ◽  
Quantitative Pcr ◽  
Statistical Analyses ◽  
Fair Agreement ◽  
Quantitative Detection ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
Noninvasive Techniques ◽  
Concordance Probability ◽  
Salivary Test

The aim of this study was to determine whether self-collected pure saliva (SCPS) is comparable to nasopharyngeal (NP) swabs in the quantitative detection of SARS-CoV-2 by RT-PCR in asymptomatic, mild patients with confirmed COVID-19. Thirty-one patients aged from 18 to 85 years were included between 9 June and 11 December 2020. A SCPS sample and a NP sample were taken for each patient. Quantitative PCR was performed to detect SARS-CoV-2 viral load. Results of SCPS vs NP samples testing were compared. Statistical analyses were performed. Viral load was significantly correlated (r = 0.72). The concordance probability was estimated at 73.3%. In symptomatic adults, SCPS performance was similar to that of NP swabs (Percent Agreement = 74.1%; p = 0.11). Thus, the salivary test based on pure oral saliva samples easily obtained by noninvasive techniques has a fair agreement with the nasopharyngeal one in asymptomatic, mild patients with a confirmed diagnosis of COVID-19.

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