Allegheny County and state officials have each started including antigen test results in a daily update of the Kovid-19 case count. The new protocol, which began in late August at both agencies, has been approved by the Center for Disease Control and Prevention Guidelines. But it can still cause confusion when the Kovid-19 data trends are analyzed. Here you need to know about the different types of Kovid-19 tests, and what they mean for interpreting the case data.
Antigen tests are different from traditional Kovid-19 tests – but both are used to indicate infection.
For months, the selection of Kovid-19 was a PCR test that searched for nucleic acids from the virus that caused Kovid-19 using mucus samples from inside the nose.
Medical Director of UPMC Clinical Laboratories Dr. These tests, said Alan Wells, are the most reliable: they are capable of “increasing” the genetic material of the virus. He said that PCR testing is more sensitive and more reliable. But it also means that it is more technically demanding, resulting in longer waiting times for results.
Antigen tests, on the other hand, search for proteins and lipids in the virus that cause Kovid-19. The test is fast – results will return in 15 minutes – but it is also much less sensitive. Wells said antigen tests cannot amplify the Kovid-19 genetic material in the same way that PCR tests can; Therefore, a person must have more virus present for antigen test to take it.
Antibody tests are completely different.
While PCR and antigen tests are to detect an existing infection, antibody testing is used to see if a person was exposed to Kovid-19 in the past. The tests detect the presence of antibodies that bind to the virus and prevent it from infecting other cells. Wells said for the most part, antibodies take 10 to 21 days to detect, because the body makes enough of them; That is why the test cannot be used to diagnose current infection.
Already, cases of coronavirus patients already recovered have been reported to be infected a second time, which Wells said is common for respiratory diseases. These viruses provide less immunity than others, which is why people need to get such frequent boosters for cold and flu vaccination. But Wells said the presence of antibodies would help a person’s immune system function faster if they received Kovid-19 for a second time, resulting in a smaller or less severe disease.
“There is evidence that these antibodies protect a person, they reduce the amount you carry and they prevent proliferation,” he said. “Herd immunity is never 100%. Swarm immunity is never complete, but it helps to reduce down (viruses). ”
When analyzing state and county data, focus on matters that are confirmed, not “probable.”
Both state and local agencies are now reporting antigen tests along with PCR tests in their daily totals.
Pennsylvania Department of Health spokesman Maggie Mumma said the change was due to an updated definition from the Council of State and Territorial Epidemiologists for Kovid-19 – a nonprofit that represents epidemiologists and advocates for public health policies is.
“This revised case definition is the updated criterion for case identification and case classification based on the continued development of the Kovid-19 pandemic,” Mammah said.
The Allegheny County Health Department began using antigen tests on August 30 to identify potential cases. Previously, cases with positive antigen tests were only potentially counted if the subject also had Kovid-19 symptoms or had close contact with a known case.
Antigen tests were authorized for emergency use by the Food and Drug Administration, but Wells said the tests have been known to produce both false positives and false negatives – Ohio Gov. Mike DeWine’s false positive examination was conducted through an antigen test in August, for example.
Wells said some states with travel restrictions would allow visitors to test negatively, but would not accept antigen tests as a testing method. The lack of a test of sensitivity leaves more room for error.
That’s why the results of the antigen test should be considered probable cases, unconfirmed, Wells said. They stated that they are best used for young individuals, such as college students, who are not at high risk of death from the disease, and positive cases should also be verified using PCR testing later.
“Especially in susceptible people,” Wells said, such as in nursing homes or with compromised immune systems, “I am a sensitive test.”
And when it comes to analyzing the data, monitoring the spike in cases that officials say are likely to reopen schools and colleges, Wells said it is best to consider only those matters Has been confirmed. He said that the most accurate way to look for changes over time is to inflate without possible long-term infections.
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