Some at-home COVID-19 tests may not be accurate, experts say

Taking a COVID-19 test in the comfort of your home sounds like a great idea but people should follow instructions and research their accuracy if they want reliable results, health experts said Wednesday.

While at-home COVID-19 diagnostic tests have been available for several months, the game changed on Tuesday when the U.S. Food and Drug Administration announced it issued an emergency-use declaration for a test by Lucira Health that provides rapid results. Unlike other tests, the user does not have to leave the house to mail or drop off a sample for processing to receive a result.

Lucira said the test, which requires a prescription, will first be offered on a limited basis in California and Florida. It is expected to be available in other locations, including New York, in early spring 2021 through health care providers.

A number of COVID-19 home testing kits are available online, requiring either a nasal swab or saliva sample. But medical experts have expressed concern that some of these COVID-19 tests may not produce accurate results and did not undergo rigorous review because of exemptions made due to the COVID-19 pandemic and the serious need for expanded testing.

"I think this is a concern for many in the testing world; tests that are performed in our laboratories go through detailed validation studies to ensure they can be used safely in the same manner every time," said Valerie Fitzhugh, an associate professor and interim chair of the Department of Pathology at the Rutgers New Jersey Medical School and Rutgers Robert Wood Johnson Medical School in New Brunswick, New Jersey.

Fitzhugh said she was worried that the clinical study done by Lucira only included a small subset of symptomatic patients and that no asymptomatic patients were included in the trial.

However, Dr. Dwayne Breining, executive director of Northwell Health Labs, said it is good news that the Lucira test not only offers a rapid result at home but uses a process that is considered highly accurate.

Breining said, to his knowledge, this is the first molecular test called the nucleic acid amplification test being offered in a home setting by nonmedical personnel. Lucira, which is just ramping up production, said it expects the test to cost about $50.

Diagnostic tests are designed to determine whether or not an individual has an active coronavirus infection. According to the FDA, there are two types of diagnostics tests. Molecular tests that search for genetic material from the virus and antigen tests that detect specific proteins from the virus.

Breining said molecular tests have proved to be more accurate, especially for people with the virus who do not have symptoms.

This is where much of testing is needed right now to control a lot of the spread we are seeing," he said of testing asymptomatic people.

He is concerned about the impact of false negatives from less reliable tests.

"What’s going to happen if someone gets a negative result and they go home and see grandma for Thanksgiving and the holidays and completely ignore all the distancing and masking precautions because they feel they are safe?" Breining said.

If a patient has symptoms that are consistent with COVID-19 but they test negative, they must go to a physician to be tested, Fitzhugh said.

"I think the most important thing that people should be aware of is that they must follow the instructions to the letter to get the most accurate result," she said. "If they cannot do so, it is best for them to see a health care provider to be tested."

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.