All virus tests are not equal

Anyone who wants a test can get one, so which should you get?

You may have a fever, cough or feel perfectly fine and want to know whether you have the new coronavirus. In Florida, the strict criteria for who may be tested for COVID-19 has lifted and anyone who wants a test can get one.

If you haven’t had a coronavirus test yet, but have an interest or a need, figuring out what type you should get and where to go can be a challenge.

“You need the right test, at the right time, for the right person, for the right result, for the right action,” said Dr. Michael Osterholm, an internationally recognized expert in infectious disease epidemiology and a leading voice during the COVID-19 pandemic, told health reporters this week.

Here’s a guide on the test types, their purposes and reliability, how long results will take to get back and what they mean.

What are the choices and differences?

Two overarching types of tests serve different purposes. By now, throughout the United States and in South Florida, both types are readily available.

Diagnostic tests

The first, usually done with a throat or nasal swab, is a diagnostic test, also known as a PCR test. These give a positive or negative result. Basically, the result will tell you whether or not you had the virus at the time the test was taken.

Diagnostic tests became available in Florida in March, initially only to people who fit certain criteria, but now to everyone.

Early on, with a lack of processing labs, the results were taking seven days or more. Commercial labs now process the tests and for the most part, results now are coming back in 24 to 48 hours.

Florida has health workers and National Guard medics administering these tests at drive-thru sites like the one at CB Smith Park in Pembroke Pines or FITTEAM Ball Park of the Palm Beaches and walk-up sites like the one in Holiday Park in Fort Lauderdale.

A worker collects the sample, sends your swab to a lab, and someone calls you with the result.

The Centers for Disease Control and Prevention points out: “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.”

Antibody tests

The second type of test is an antibody test, also known as a serology test, done by a blood draw.

Antibody tests are the newest to the South Florida market and designed to tell whether you may have overcome COVID-19 or been exposed to the virus long enough to develop an immune response.

The antibody tests are not designed to show if you are currently infected. If you suspect you were infected in recent months, or exposed and have not shown symptoms, you may want to get the antibody test.

Are there variations?

Within the two major categories, variations continue to roll out. Within the diagnostic category, these are the variations:

Rapid

Some tests that have received approval are called rapid tests. With these, the results come back much quicker — 15 to 45 minutes. These tests are being used at hospitals and emergency rooms — and now some South Florida nursing homes — to help health care professionals triage patients in need of urgent care.

“The results help us better manage the patients, to know whether we need to isolate them or not,” said Ed Peterson, director of laboratory services for Memorial Healthcare System.

As more of these tests are produced, health experts envision them becoming a tool in workplaces to learn quickly whether employees are infected.

Antigen

More recently the FDA has approved an antigenbased diagnostic test. It may seem confusing but this new category has the same purpose as the PCR tests — to learn whether someone is positive for the virus. Antigen tests, done with a nasal swab, look for a little part of the outside coating of the virus and tells whether the virus is there or not. Antigen tests are cheaper to make and deliver results in minutes. “They give us another opportunity to detect the virus and they may be an easier test to get,” Peterson said.

While positive results from antigen tests are highly accurate, there is a higher chance of false negatives than from the PCR tests.

Saliva

Imagine spitting into a tube and learning quickly if you are infected with COVID-19.

On May 8, the FDA authorized the first COVID-19 diagnostic test using home-collected saliva samples. Anyone with a prescription can get the test. This is how it works: You are shipped a collection kit. Once you collect your saliva sample, you return it to the Rutgers Clinical Genomics Laboratory in a sealed package for testing. Then, the lab notifies you of results within 24 hours. Right now the tests are largely for use in New Jersey with a doctor’s prescription, but other labs may be able to use Rutgers data to expand this type of testing.

At-home kits

Instead of going to a test site, it has become possible to do a diagnostic test at home. These tests, called Pixel by LabCorp, contain supplies to collect samples, including a nasal swab which you send back to the lab for testing. Unlike other swab-based tests, Pixel uses swabs that need to go only as far as the nostril, instead of deeper into the nasal passage.

For now, LabCorp is sending kits only to healthcare workers and first responders who may have been exposed to the virus or are symptomatic. In the coming weeks, LabCorp says it will make the test available to consumers.

Which test should I get?

Do you imagine yourself saying, “Hey boss, I don’t have the coronavirus?”

If you want to prove you are clear of the virus and ready to work, or if you have symptoms and want confirmation, you will want the diagnostic test.

Let’s say you suspect your bad flu in January was actually COVID-19. if you think you might have had the virus in the past without a diagnosis or even without symptoms, you might want to get an antibody test. A word of caution, though: Medical experts still don’t know how long antibodies will protect you from getting the virus in the future.

Dr. Daniel Perez, an infectious disease specialist with MDVIP, offers both at his Plantation office.

“People who have symptoms should get the diagnostic test,” Perez said. “The antibody test is to determine exposure.”

“Some people are hoping they come back positive for antibodies,” he said. “But even if they do, the question is how long will antibodies last? We don’t know the answer yet. We suspect and extrapolate from others coronavirus that it’s one to two years, but we really don’t know.”

Dr. Lisa M. Lee, associate vice president for research and innovation at Virginia Tech, adds this caveat: “Unfortunately we do not know yet whether the COVID-19 infection will be one of those infections that we get once, or again and again.”

When the antibody test is given to a larger population, the surveillance can help a school, county or workplace learn what percentage of the population has immunity to the virus.

Will the test hurt?

Julie Talenfeld of Plantation had both the antibody test and the diagnostic test at her primary care doctor’s office. She found both tests slightly uncomfortable. With the diagnostic test, a swab must go up your nose high enough or in your throat deep enough to collect a quality sample.

“They were both quick. I was nervous to get them but neither was really a big deal,” Talenfeld said.

Learning she was negative and hadn’t been exposed was a relief, she said.

Are the test results reliable?

Within each category, there is a huge range of quality, and both types are riddled with errors depending on which manufacturer made them and who validated them.

With diagnostic tests, the instances of false negatives would be linked to not getting a good enough swab or the virus being too far down in the chest.

However, the FDA is warning that Abbott Laboratories’ 15-minute diagnostic test may be missing COVID-19 cases, falsely clearing patients of infection. Regulators said they are requiring Abbott to conduct follow-up studies on the test’s accuracy.

You need to be particularly careful with antibody tests. The FDA loosened its approval standards in order to get more antibody tests out on the market quickly, allowing more than 120 manufacturers and labs to bring the tests to market without an agency review.

Complaints quickly began to grow that unauthorized tests were flooding the market. The FDA since clamped down on companies selling antibody tests and is requiring companies to submit proof their tests work. The agency lists the tests that have Emergency Authorization Use and details each manufacturer’s performance.

“You want to make sure you are using a test that is FDA-approved or has emergency-use authorization,” said Virginia Tech’s Lee. “Antibody tests vary a lot in how well they work and how accurate they are. The most important thing is what it tells you and what it doesn’t. Even if you assume it’s 100 percent accurate, if you get a positive, what it tells you is at some point you were exposed. That only matters if it turns out people who had the virus in the past can’t get it again.”

Where should I go to get tested?

For a diagnostic test, you can go to any of the statesupported sites, urgent care offices or visit your primary care doctor. The CVS minute clinic is offering the diagnostic tests in some states, including Florida and a site in Boca Raton. Walgreen’s offers drive-thru testing in 15 states including Florida.

The capability to collect your own samples at home and send them to a lab could become available in the next few months.

For the antibody test, anyone with a doctor’s prescription can go to a Quest Lab to have blood drawn and processed. You can also sign up for a test through QuestDirect. The tests also are available at primary care doctors’ offices and some state-run drive-thru sites, including the Hard Rock Stadium in Miami Gardens.

What is the cost of a test?

Federal legislation, signed into law March 18, makes coronavirus tests available at no cost. That means no co-pays, no deductibles, no co-insurance charges. Free.

But it’s always a good idea to check with your insurer and health care provider about any out-ofpocket expenses for the doctor’s appointment (or telehealth appointment) to determine if you need a test. If you’re treated in any way besides just getting a test, you could end up with a bill.

What happens if I test positive?

Regardless of where you get tested, a medical professional will call you with the result. Most people who are diagnosed with COVID-19 are able to recover at home. If you have severe symptoms you will need to get medical attention. If you develop emergency warning signs for COVID-19 — trouble breathing, persistent pain or pressure in the chest, major exhaustion — get medical attention.

You will need to get retested after 14 days to learn whether the virus is completely out of your system.

How long does it take to recover from the virus?

This answer isn’t going to make you feel better. The truth is the length of time each person has the virus varies.

The World Health Organization has found the median time from onset to recovery for mild cases is about two weeks, and up to about six weeks for patients with severe cases.

Perez said in the patients he has seen the average time to clear the virus is about two weeks, but some take longer.

“I have a case in the hospital of someone who had their first positive nasal swab six weeks ago,” he said. “Something from that person’s immune system has not been able to clear the infection well.”