Officials discuss test accuracy

UTICA, N.Y. » COVID-19 testing is becoming more widespread and accessible, but how accurate are the results?

According to the Centers for Disease Control and Prevention (CDC), Goodrx, and other medical-related facilities, a positive result for COVID-19 is quite likely to be true. False positives are difficult to achieve.

Negative test results, on the other hand, can be a little less accurate for many reasons. Depending on when the test was taken, how the test was administered, and the detectable levels of the virus in the individual’s system at the time, a test could come back negative even though the individual is actually carrying the virus.

Some early research would suggest that the chance of a false negative for a COVID-19 test could be as high as 30%, but this data is still being evaluated and has not been peer-reviewed.

The Centers for Disease Control and Prevention (CDC) states that Fda-authorized molecular tests are “are highly accurate” and that “a negative test result for a sample collected while a person has symptoms likely means that the COVID-19 virus is not causing their current illness.”

Additionally, the CDC notes that “If you test negative for COVID-19 by a viral test, you probably were not infected at the time your sample was collected. However, that does not mean you will not get sick. The test result only means that you did not have COVID-19 at the time of testing.”

This is why the timing of a COVID-19 test is so important. A seemingly uninfected individual could get tested on Tuesday, but then have detectable levels of the virus on Wednesday. In this instance, their negative test result they receive a day later might not seem accurate or helpful.

A test result’s accuracy can also vary depending on the type of test being administered.

ARUP Laboratories, a national nonprofit and academic reference laboratory, outlined the differences in sensitivity in COVID-19 molecular test samples from nasopharyngeal (NP) swabs (deep in the back of the nose), oropharyngeal (back of the throat) swabs, and samples taken from blood or saliva. The most sensitive swabs are better able to detect the virus.

The NP swab is what is commonly shown on TV, depicting a long swab being administered to the very back of the nose through the nostril. This swab reaches the nasopharynx, which “appears to have the highest concentration of virus,” compared to other areas, making it more likely to collect the virus if it’s present.

However, it can also be technically difficult to get a good sample from this area, which means if not collected correctly, the swab may yield an inaccurate result, according to ARUP Laboratories.

Additionally, any test that is not conducted properly, not just a COVID-19 test, is likely to have faulty results.

Oneida County Health Director Phyllis Ellis agrees that false negatives can happen, as well as “indeterminate” results, but this is not overly common.

She recommends “If you do have symptoms and you feel that you are positive, but your test is negative,

definitely contact your health care provider.”

This is important to determine if there could be something else going on with the patient’s health that might not be COVID-19 related, she explained. A health care provider may also decide that a second round of testing is necessary, among other guidance.

No matter the issue an individual may have with a test, Ellis assures residents that a second test can always be taken. So if a “false negative” does occur or is suspected, a second test will likely reveal the truth.

What is even more compelling, is even if some individuals do receive a false negative result, there have been many who have received positive results who otherwise had no idea they were carrying the virus.

“Now that [testing] is [more] open...it’s important to know that many tests are coming back from people that have said that they haven’t had any symptoms,”

Ellis reported.

Because these individuals chose to get tested for whatever reason, they are now aware that they could spread COVID-19 to others based on their positive status. This is why testing is crucial, Ellis explained, as it pin-points the virus and helps individuals isolate it.

In general, Ellis said that she’s confident with the testing being administered in Oneida County. “Most [tests] that we know of are very accurate. They’re being done under strict laboratory guidelines,” she explained.

“It’s not difficult, it doesn’t hurt, it’s pretty painless, and it doesn’t cost anything. You should [get tested] for your sake, your family’s sake, your community’s sake, your coworker’s sake—get your test,” Ellis concluded.

Whether a test was conducted or not, anyone who thinks they have COVID-19 or are showing symptoms should take the proper precautions to limit the spread of the disease to others, she

said. Everyone should continue to wear masks, social distance, and practice good hygiene. This is the greatest defense against this often invisible threat.

As of May 22, 17 new cases were reported in Oneida County, 13 of which were nursing home residents. The total cases reported in the county now stands at 836. A total of 456 cases have recovered. To

date, 32 cases are hospitalized in Oneida County, and three are hospitalized outside of the county. The total number of deaths stands at 37.

There will be no live press briefing on Monday to observe Memorial Day, but Oneida County COVID-19 data will be updated online.

For more information, visit the county website.

BY CARLY STONE CSTONE@ MEDIANEWSGROUP.COM A mobile COVID-19 test site located in Wampsville, N.Y.