We use cookies to understand how you use our site and to improve your experience. This includes personalizing content and advertising. To learn more, click here. By continuing to use our site, you accept our use of cookies. Cookie Policy.

Features Partner Sites Information LinkXpress hp
Sign In
Advertise with Us

Download Mobile App





Rapid COVID-19 Tests Return Minimal False Positives and Moderately High False Negatives, Finds New Study

By LabMedica International staff writers
Posted on 09 Apr 2021
A new study has found that rapid COVID-19 antigen tests have very low false positive rates but a moderately high false negative rate.

Researchers from the University of Southern California (USC; Los Angeles, CA, USA) conducted the study to see how well inexpensive, easy-to-use COVID-19 tests might work as a screening tool for schools to help them reopen safely. More...
The tests show promise for schools, especially if they use serial testing, such as twice a week.

Children arriving with their parents at a walk-up testing site during the winter surge of COVID cases were given the opportunity to be tested for COVID twice - once with a rapid antigen test and once with the “gold standard” PCR test, to confirm the results of the rapid test. Overall, 774 children ages 5 to 17 years old took both tests. The study found that the rapid antigen tests have very low false positive rates but a moderately high false negative rate. In other words, the tests rarely identified someone as positive who was not but did occasionally identify someone as negative who in fact had COVID.

Among asymptomatic children who had COVID, as measured by the PCR test, the rapid antigen test identified about 50% of COVID-19 cases. The reason the rapid antigen test failed to identify many COVID-19 cases in children was because the majority of children tested had low viral loads as measured by Ct values - the number of times one needs to amplify the test sample to detect the genetic material of the virus. The test was over 90% accurate when focused on the sample of children with high viral loads who were very likely to be infectious. The test was about 99% accurate among asymptomatic children who did not have COVID-19. That is, the test gave a false positive result in one out of 100 asymptomatic children. The researchers suggest that the rapid tests, which require inserting a swab about a half-inch up the nose, could be administered by school staff or be self-administered with supervision. In addition, serial testing could allow schools to relax social distancing rules.

“The good news is that the false negative rate is low in kids likely to be infectious, as measured by viral load,” said Neeraj Sood, who directs the COVID Initiative at the USC Schaeffer Center for Health Policy and Economics. “Serial rapid testing may help compensate for missing the virus in the earliest stage of infection. If you’re testing these kids every four days or every five days, then there’s a good chance that you will catch them when they’re infectious.”

Related Links:
University of Southern California


Gold Member
SARS-CoV-2 Reactive & Non-Reactive Controls
Qnostics SARS-CoV-2 Typing
3-Part Differential Hematology Analyzer
Swelab Alfa Plus Sampler
New
Rapid Molecular Testing Device
FlashDetect Flash10
New
Gram-Negative Blood Culture Assay
LIAISON PLEX Gram-Negative Blood Culture Assay
Read the full article by registering today, it's FREE! It's Free!
Register now for FREE to LabMedica.com and get access to news and events that shape the world of Clinical Laboratory Medicine.
  • Free digital version edition of LabMedica International sent by email on regular basis
  • Free print version of LabMedica International magazine (available only outside USA and Canada).
  • Free and unlimited access to back issues of LabMedica International in digital format
  • Free LabMedica International Newsletter sent every week containing the latest news
  • Free breaking news sent via email
  • Free access to Events Calendar
  • Free access to LinkXpress new product services
  • REGISTRATION IS FREE AND EASY!
Click here to Register








Channels

Molecular Diagnostics

view channel
Image: The ONC IN-CYT platform leverages cross indication biomarker cyto-signatures (Photo courtesy of OraLiva)

AI-Powered Cytology Tool Detects Early Signs of Oral Cancer

Each year, 54,000 Americans are diagnosed with oral cancer, yet only 28% of cases are identified at an early stage, when the five-year survival rate exceeds 85%. Most diagnoses occur in later stages, when... Read more

Hematology

view channel
Image: The microfluidic device for passive separation of platelet-rich plasma from whole blood (Photo courtesy of University of the Basque Country)

Portable and Disposable Device Obtains Platelet-Rich Plasma Without Complex Equipment

Platelet-rich plasma (PRP) plays a crucial role in regenerative medicine due to its ability to accelerate healing and repair tissue. However, obtaining PRP traditionally requires expensive centrifugation... Read more

Immunology

view channel
Image: PD-1 protein blockade is the standard treatment for advanced melanoma among the different types of immunotherapy (Photo courtesy of 123RF)

Precision Tool Predicts Immunotherapy Treatment Failure in Melanoma Patients

Melanoma, though accounting for only about 4% of skin tumors, is the deadliest form of skin cancer due to its high potential to metastasize. While immunotherapy, especially PD-1 protein blockade, has revolutionized... Read more

Pathology

view channel
Image: Researchers have developed a novel method to analyze tumor growth rates (Photo courtesy of Adobe Stock)

Novel Method To Analyze Tumor Growth Rates Helps Tracks Progression Between Diagnosis and Surgery

Patients diagnosed with breast cancer often worry about how quickly their tumors grow while they wait for surgery, and whether delays in treatment might allow the disease to spread beyond the point of cure.... Read more
Copyright © 2000-2025 Globetech Media. All rights reserved.