Confused about COVID-19 tests? Here’s what to know
If you’re confused about coronavirus testing, you’re not alone.
We asked an expert to tell us about the different types of tests that you may have heard about and what the results tell us.
The three tests are:
• PCR test (RNA test or molecular test)
• Antigen test (detects proteins)
• Antibody test (serology test or blood test)
“The PCR is the gold standard for testing,” said Elizabeth Dunton, NP, chief operating officer for physician practices for Medical Affiliates of Cape Cod (MACC), and a nurse practitioner. MACC falls under the Cape Cod Healthcare (CCHC) umbrella of services.
CCHC offers the PCR (polymerase chain reaction) test at drive-through testing sites at Falmouth Hospital and Cape Cod Hospital, which are open seven days a week. Appointments are required.
The PCR test uses a swab inserted into the nasopharynx to collect a sample. Molecular technology amplifies (produces multiple copies of) the viral RNA.
“It's 98 percent sensitive, which means that the likelihood of a false negative is very low,” said Dunton. “This is the test that is required by the state of Massachusetts to avoid quarantining after returning from high-risk states.”
There are three pathways that lead to testing, Dunton said.
“You can be tested because you are symptomatic, because you've been exposed to someone with COVID or because you're asymptomatic but want to be tested. That last category is a little broad, but the most frequent reason is related to travel. For example, you are returning from a state that Massachusetts requires that you test or quarantine upon your return.
For symptomatic or exposed patients, insurance companies will pay for the test with a physician order. People in the third category (asymptomatic patients) are charged $110. Results are available in 24 to 72 hours.
CCHC physicians can use the new Epic electronic health records (EHR) system to order a test; other physicians submit requests by fax.
“If patients are symptomatic or have been exposed, they should evaluated by a provider, for an assessment, as well as care and treatment if needed,” Dunton said. “The level of exposure and the timing of the exposure may affect what you do next, as far as quarantining and when to test.”
The PCR test is administered by nurses working in the large drive-through tents.
“They've been doing this since the tent opened in March and have really been, in my mind, some of our heroes at Cape Cod Healthcare through this pandemic,” she said.
The tents are sturdy enough that testing can be done no matter what the weather.
“From the patient's perspective, the drive-through process is seamless,” she said. “You stay in your car the entire time. You identify yourself with your license and they verify that we have an order and that you're on our schedule. The nurses and technicians are all in full PPE since infection control is paramount.
“They will administer the swab up the nose to collect a sample. I would say it's uncomfortable - it can make your eyes water - but it's over very quickly. It’s not a pleasant test, but we try to make it a pleasant experience. I get patient feedback almost daily saying that it was so quick, and the nurses were amazing.”
The antigen test is less sensitive than the PCR test, according to Dunton. “It can miss people who do have COVID. Because of the likelihood of false negatives, Cape Cod Healthcare doesn’t use that test,” she said.
“Antigen tests are specific, meaning if you test positive you are likely positive, but antigen tests are more likely to produce false negatives, meaning if you test negative you may still have the virus.” Because of its lower accuracy, it is not approved for testing related to travel restrictions.
The antibody test is different in that it shows whether you had COVID in the past. It is not a diagnostic test.
“If you get COVID, your antibodies will go up and theoretically stay up for an extended period of time and help you to become immune to the virus.,” she said. “If the test shows you have the antibodies, you may have had COVID. It is specific to coronavirus, but not specific to COVID-19, so you could have had another coronavirus. There are some strains of the common cold that are considered a coronavirus, so you have to consider the results with that in mind.”
It's not yet known whether having and recovering from COVID-19 leaves you immune from it, she said.
“This test is not something that we recommend for patients, but there is some demand for it,” she said.
The antibody test is done via a blood draw at Cape Cod Hospital or Falmouth Hospital.
Learn more about COVID-19 testing at Cape Cod Healthcare.