The new COVID-19 test, which is fast and cheap, could strengthen US screening efforts

(HealthDay)-The new rapid COVID-19 test, approved last week, is probably not the most reliable option to determine if someone is infected.

But it’s cheap, fast, and when used correctly, it’s the basis of a screening strategy that keeps Americans safe when they go back to school and work, infectious disease experts say.

The Binax NOW COVID-19 Ag card created by Abbott Laboratories is an antigen test, A type of scan that searches for specific structural proteins of coronavirus that are formed during infection. The test produces results in less than 15 minutes and costs $5, Abbott said.

Antigen tests are famous for producing many false positiveDr Gary Procop, Dean and Co-Chair of the Enterprise Laboratory Stewardship Committee at Cleveland Clinic, Ohio, shows that people are infected when they are not.

He also said that if the test was used properly, it would be all right as a screening tool to keep people infected with SARS-CoV-2 out of crowded schools, basketball courts and assembly lines. ..

“Every time we do a screening test, we really want a lot of false positives because we want to catch everyone with the disease,” Prokop said.

What is important is that antigen testing should be the first in a two-step screening process, he said.

Every person who tests positive must undergo a confirmatory PCR test. This is a newer, more complex and more accurate type of molecular scan looking for new genetic material CoronavirusSaid Procop.

“Many people prefer antigen testing as their first screen because it’s cheap and fast, and you get positive people who don’t want to sit next to an airplane,” Prokop said. “But you have to follow it up with PCR tests to eliminate false positives.”

Abbott’s test is promising, and the White House has signed an agreement with the company to buy 150 million test cards for $760 million. Barons..

The agreement was made one day after Abbott announced approval for the US Food and Drug Administration emergency trials. The test can only be performed by medical professionals and is not approved for home use.

The test looks like a greeting card. The doctor or nurse drops the test solution into a small well on the card and slides the nasal swab sample onto the chemical. The top of the card will close and the results will be displayed within 15 minutes. One line is negative and two lines are positive.

Abbott’s comment Clinical trial Involvement of patients tested within the first 7 days of symptom onset revealed that BinaxNOW had a sensitivity of >97% and a specificity of >98%. That is, only 3 out of 100 tests generate false positives and less than 2 out of 100 tests return false negatives.

Antigen testing generally tends to be less sensitive, with some testing down to 70%, says Dr. Ameja Adalja, a senior researcher at the Johns Hopkins Health and Safety Center in Baltimore.

But antigen tests are also very specific, and rarely give false-negative results, he said.

Given all this, cheap and rapid antigen testing should be good enough for asymptomatic individuals to focus on the problem and be contagious or otherwise.

“When screening asymptomatic individuals such as colleges and sports teams, tests that are as sensitive as PCR may not be needed,” he said.

PCR tests, on the other hand, are much more accurate.

“That’s how we diagnose acute infections,” said Adalha. “This is a very sensitive test. It detects the genetic material of the virus at very low levels. It can be positive even after people recover and lose their infectivity.”

However, testing requires more processing time because PCR samples need to go to the laboratory, says Adalja. They also sometimes need the missing chemicals, further delaying the results.

Procop said he relies on PCR to test people who are clearly ill in critical situations, such as before being admitted to an intensive care unit.

“Antibody tests may miss COVID-19 infections, so if you try to put someone in your ICU on this basis, you will never use them. Infect other patients or health care workers.” There is a real risk.” Procop said. “I can’t be wrong in that situation.”

But Procop said Antigen test It can be a good screening tool if you follow up with a PCR test. He likened the strategy to an early HIV test, where a rapid positive screening immunoassay was followed by a more detailed clinical test to confirm the diagnosis.

“Only patients who have overcome both disabilities are considered to have HIV and were called HIV positive,” Prokop said.

He hopes the new test will detect what the United States has missed since the beginning of the pandemic, the COVID-19 case, and foretell a national testing strategy to protect the masses.

“We know how to screen a population. We do a screen test, then a confirmation test. Why don’t we do that now?” Procop told the pandemic to “make people crazy. I am adding.”

“They abandoned everything we know over the last 100 years, decided to recreate it from scratch, and speculated what they were discovering. Trial and error is trial and error. “The above.

Copyright © 2020 HealthDay.. all rights reserved.