Northwell Health doctor: Educate yourself on types of COVID-19 test kits

Medical experts are advising Long Islanders to educate themselves on the different types of COVID-19 test kits to figure out which one works best for them.

There has been a shortage of test kits nationally, but President Joe Biden said during a news conference on Tuesday that the federal government is expanding testing sites across the country and plans to purchase 500 million at-home tests for free public distribution.

Biden did not say which at-home tests would be available. But rapid antigen tests, which deliver results within minutes, might work well if they are administered before visiting relatives or attending a party, said Dr. Dwayne Breining, executive director of Northwell Health Labs.

A PCR, or polymerase chain reaction, test does not deliver rapid results, but is more sensitive and may be a requirement before a student returns to college or someone visits a hospital patient, Breining said.

"I think we are entering into a period where the guidance is going to be changing fairly rapidly based on what we learn about the new omicron variant," he said.

New York Gov. Kathy Hochul on Monday called on the federal government to supply more test kits. Hochul also said the state will make at-home PCR tests available through an online portal, and send millions of rapid antigen tests to counties, which will distribute them to schools and other locations.

Using rapid tests to determine whether a student has COVID-19 has been viewed as a key way to keep schools open during the pandemic. "About 2 million will be going to the school districts because we want to make sure that our kids come back in January, that we are keeping them in school," Hochul said during a news conference on Monday.

Polymerase chain reaction is a laboratory technique that copies the genetic material of the virus so it can be detected, according to the National Human Genome Research Institute.

"They’re extremely accurate, and they’re specific," Breining said. "They usually don’t generate any significant false positives or false negatives."

PCR tests take longer to process and usually require specialized lab equipment.

Antigen tests measure the presence of viral protein from the SARS-CoV-2 virus. While not as sensitive as the PCR test, antigen tests are important because they are relatively inexpensive, can be used anywhere and provide results quickly, Breining said.

Both tests require a nasal swab sample. For the PCR test, it will be collected by the individual and mailed to a lab. State officials said people who use the PCR tests through the portal will get results within 48 hours.

Some antigen rapid tests, such as the iHealth COVID-19 Antigen Rapid, deliver results within 15 minutes. For those tests, the nasal swab sample is placed in a tube with a solution and stirred. Three drops of the mixed solution are placed on a sample port of a test card. If one line appears, the sample is negative, and if two lines appear, the sample is positive.

According to the iHealth website, a package of two tests costs $13.98, plus shipping.

The Pixel PCR test home collection kit sells for $124.99 on the CVS website. As of Tuesday, Pixel and several other home tests were sold out on the website. And many Long Islanders searching for at-home kits were met with empty shelves at pharmacies and stores.

Breining said people unsure of which test to use should consult with their doctor, but also check public health websites such as the Centers for Disease Control and Prevention.

"If you're gathering with people that are not in your household, it's a good idea to get yourself tested before you go in and gather," he said. "That way it keeps everybody safer and it reduces the spread."

By Lisa L. Colangelo

lisa.colangelo@newsday.com@lisalcolangelo

Lisa joined Newsday as a staff writer in 2019. She previously worked at amNewYork, the New York Daily News and the Asbury Park Press covering politics, government and general assignment.