COVID-19 Saliva Tests Could Detect Silent Carriers
By LabMedica International staff writers Posted on 29 Sep 2020 |
Testing self-collected saliva samples could offer an easy and effective mass testing approach for detecting asymptomatic COVID-19, according to researchers.
Scientists at Hokkaido University (Hokkaido, Japan) have demonstrated a quick and effective mass testing approach using saliva samples to detect individuals who have been infected with COVID-19 but are still not showing symptoms. The scientists tested and compared the nasopharyngeal swabs and saliva samples of almost 2,000 people in Japan who did not have COVID-19 symptoms. Two different virus amplification tests were performed on most of the samples: the PCR test, which is now well-known and widely available around the world, and the less commonly used but faster and more portable RT-LAMP test.
The number of positive and negative results in all samples was very similar, with the nasopharyngeal swabs and saliva samples able to detect those with the infection in 77-93% and 83-97% of subjects, respectively. Both two tests were also able to identify those without the infection in greater than 99.9% of subjects. The virus loads detected in nasopharyngeal swab and saliva were equivalent and highly correlated.
“PCR sensitivity is much higher than previously thought 70% that came from initial data of symptomatic patients,” said Hokkaido University researcher Takanori Teshima, who led the study. While finding both nasopharyngeal and saliva samples have high sensitivity and specificity to the SARS-CoV-2, Teshima said “Saliva testing has significant logistic advantages over the commonly used nasopharyngeal swab testing.” “Self-collection of saliva is painless for examinees, and more importantly, it eliminates the close contact with the examiners, reducing the risk of viral exposure.”
“We also found that it is unlikely that the sensitivity of RT-LAMP is significantly less than that of the PCR test, suggesting that it might be a useful alternative for diagnosing COVID-19 infection, especially where diagnosis is required at the point of sample collection, like in sports venues or at airports,” added Teshima.
Related Links:
Hokkaido University
Scientists at Hokkaido University (Hokkaido, Japan) have demonstrated a quick and effective mass testing approach using saliva samples to detect individuals who have been infected with COVID-19 but are still not showing symptoms. The scientists tested and compared the nasopharyngeal swabs and saliva samples of almost 2,000 people in Japan who did not have COVID-19 symptoms. Two different virus amplification tests were performed on most of the samples: the PCR test, which is now well-known and widely available around the world, and the less commonly used but faster and more portable RT-LAMP test.
The number of positive and negative results in all samples was very similar, with the nasopharyngeal swabs and saliva samples able to detect those with the infection in 77-93% and 83-97% of subjects, respectively. Both two tests were also able to identify those without the infection in greater than 99.9% of subjects. The virus loads detected in nasopharyngeal swab and saliva were equivalent and highly correlated.
“PCR sensitivity is much higher than previously thought 70% that came from initial data of symptomatic patients,” said Hokkaido University researcher Takanori Teshima, who led the study. While finding both nasopharyngeal and saliva samples have high sensitivity and specificity to the SARS-CoV-2, Teshima said “Saliva testing has significant logistic advantages over the commonly used nasopharyngeal swab testing.” “Self-collection of saliva is painless for examinees, and more importantly, it eliminates the close contact with the examiners, reducing the risk of viral exposure.”
“We also found that it is unlikely that the sensitivity of RT-LAMP is significantly less than that of the PCR test, suggesting that it might be a useful alternative for diagnosing COVID-19 infection, especially where diagnosis is required at the point of sample collection, like in sports venues or at airports,” added Teshima.
Related Links:
Hokkaido University
Latest COVID-19 News
- New Immunosensor Paves Way to Rapid POC Testing for COVID-19 and Emerging Infectious Diseases
- Long COVID Etiologies Found in Acute Infection Blood Samples
- Novel Device Detects COVID-19 Antibodies in Five Minutes
- CRISPR-Powered COVID-19 Test Detects SARS-CoV-2 in 30 Minutes Using Gene Scissors
- Gut Microbiome Dysbiosis Linked to COVID-19
- Novel SARS CoV-2 Rapid Antigen Test Validated for Diagnostic Accuracy
- New COVID + Flu + R.S.V. Test to Help Prepare for `Tripledemic`
- AI Takes Guesswork Out Of Lateral Flow Testing
- Fastest Ever SARS-CoV-2 Antigen Test Designed for Non-Invasive COVID-19 Testing in Any Setting
- Rapid Antigen Tests Detect Omicron, Delta SARS-CoV-2 Variants
- Health Care Professionals Showed Increased Interest in POC Technologies During Pandemic, Finds Study
- Set Up Reserve Lab Capacity Now for Faster Response to Next Pandemic, Say Researchers
- Blood Test Performed During Initial Infection Predicts Long COVID Risk
- Low-Cost COVID-19 Testing Platform Combines Sensitivity of PCR and Speed of Antigen Tests
- Finger-Prick Blood Test Identifies Immunity to COVID-19
- Quick Test Kit Determines Immunity Against COVID-19 and Its Variants