When and how to get tested, plus the latest on the testing shortages
If you’ve tried to get tested for coronavirus in the United States but have been turned away, you’re not the only one. As the country grapples with the rapid spread of the coronavirus, tests have been frustratingly hard to come by. But testing is now starting to ramp up.
Experts say testing as many people as possible for the new coronavirus is crucial to slow the rate of infection, or flatten the curve. Public health officials rely on testing to find “hot spots” of the disease, identify which communities are most at risk, and track how widespread the disease is. Once someone knows that they have the virus, they can self-quarantine and stay away from other people.
“We want to be able to tell people that they’re infected because we want them to stay home,” said Karen Carroll, MD, a clinical microbiologist at the Johns Hopkins University School of Medicine, in a March 13 call with reporters. “If we can do this more quickly, it should interrupt the spread.”
An online effort called the COVID Tracking Project estimates that the country has so far processed around 100,000 tests as of March 19. That’s less than the 274,000 done in South Korea.
Testing shortages in the United States have hampered these efforts. On February 6, the U.S. Centers for Disease Control and Prevention announced that it had begun shipping testing kits to certain state and local health labs. But those initial kits were flawed and didn’t work properly, leading to testing delays. The CDC has since sent new test kits to all 50 states and Washington, D.C., but tests are still in short supply in many places.
“The availability is variable,” Carmen Wiley, PhD, president of the American Association for Clinical Chemistry, tells Elemental.
As of March 17, the CDC and state labs have processed around 33,000 tests, but that number doesn’t represent a full picture of the country’s total testing capacity. Other labs, including commercial and university-based labs, are coming online with their own testing capabilities. An online effort called the COVID Tracking Project estimates that the country has so far processed around 100,000 tests as of March 19. That’s less than the 274,000 done in South Korea, which has also been hit hard by the coronavirus.
What’s being done about the testing shortage?
On February 29, the U.S. Food and Drug Administration issued a policy to help expedite the availability of more tests. The policy gave certain U.S. labs permission to develop and validate their own coronavirus tests. In response, diagnostics companies Roche and Thermo Fisher announced that they would begin manufacturing and shipping millions of tests to help alleviate the shortage. Commercial labs like LabCorp and Quest Diagnostics are making tests available, too. Many university medical centers have also developed their own tests and are quickly trying to ramp up the number of tests they can process daily. These efforts could dramatically increase testing availability soon.
Do I need to get tested?
Initially, the CDC recommended testing only people who had symptoms — fever, cough, and shortness of breath — and an obvious exposure to the virus. But on March 4, it changed the criteria to include anyone displaying symptoms of Covid-19, regardless of any known exposure, as long as they have a doctor’s order.
If you have mild symptoms but are young or otherwise healthy, a health care provider may tell you to stay home and rest. Older adults, people who are immunocompromised, and those with underlying medical conditions like heart disease, diabetes, and lung disease are being prioritized for testing, even if they only have mild symptoms.
If you develop emergency warning signs like difficulty breathing, persistent chest pain or pressure, confusion, or bluish lips or face, the CDC recommends that you seek medical attention immediately.
If you don’t have symptoms but think you may have been exposed to the virus, you probably won’t be able to get tested right now. Many sites are not testing people who are asymptomatic because there simply aren’t enough tests to go around yet.
“If we start doing that, we’re going to use up our inventory and we won’t have tests available for people who need them,” says Carroll. It’s also unclear if the test works as well in people who don’t present with symptoms, she says. People who are asymptomatic can still carry the virus, so it’s important to practice social distancing.
I think I was exposed to coronavirus. How long is it going to take for me to test positive for the virus?
“We don’t know the answer to that,” Anthony Fauci, MD, director of the National Institute of Allergy and Infectious Diseases, said in a March 18 interview with the Journal of the American Medical Association.
If you get exposed to the coronavirus, symptoms can appear anywhere between two and 14 days afterward, with an average of about five days. Scientists don’t yet know when to test patients to get the most accurate readout. They do know that the virus needs time to enter the body’s cells and start replicating. That means if you were to get tested the day after you were exposed, your results would probably be negative. “It’s not going to happen immediately,” Fauci says. “When you get to the point where you’re symptomatic, you’re almost always positive then.”
Where can I get tested?
The CDC recommends first calling your primary care doctor or regular health care provider, who will ask you certain screening questions to determine whether you should get tested. Right now, patients need a doctor’s order to get a test. Your doctor’s office can’t perform the testing but can recommend a nearby testing location.
If you don’t have a primary care provider, call your state health department for information about testing. Drive-through testing sites, where you can be swabbed for the virus without leaving your car, are becoming available in several places around the country. Drive-through testing has worked well in South Korea to curb the spread of the disease.
For those with mild symptoms or no symptoms, it may take three or four days to get results.
How does the coronavirus test work?
At most testing locations, a health care worker will swab the inside of your nasal passage for a sample of cells. Then your sample will be sent to a lab for processing. The tests developed by the CDC, diagnostic companies, and academic medical centers all use a routine lab technique called polymerase chain reaction, or PCR, to confirm the presence of the virus’s genetic material in your cells. PCR works by amplifying the tiny amounts of genetic material from a nasal swab into large enough quantities that can be analyzed. If the virus’s genetic material is found in your cells, then you are infected with the virus.
How soon will I get my results back?
It varies. It could be as soon as 24 hours or up to four days, depending on a few factors. Your age, risk level, and the severity of your symptoms will likely play a role, Wiley says. Right now, health care workers are prioritizing the sickest and most at-risk patients, like older people and those who may be immunocompromised. These people are likely to get their tests results sooner, sometimes within 24 hours. For those with mild symptoms, it may take three or four days to get results. Another factor is whether your testing location can run the test in-house or has to send its tests to another lab to be processed. If you go to an academic medical center that has the ability to test samples, your results will likely come back faster.
How accurate is the test?
PCR is a widely used lab test and is generally very accurate, though Wiley says inaccurate results may arise for other reasons. You could get a false negative — a test result that says you don’t have the condition, even when you do — if the sample isn’t collected properly, she says. You could also have a false negative if the virus’s genetic material degrades during shipping or storage.
There’s also the slight possibility of a false positive — a result saying you have the condition when you actually don’t. This could happen if your sample gets contaminated in the lab or mixed up with another patient’s. Wiley says people shouldn’t be too concerned about these issues because they’re rare.
How much will it cost me to get tested?
Congress passed a coronavirus relief package, which President Trump signed into law on March 18, that makes testing free for all Americans. Some insurance companies are also waiving fees for coronavirus treatment. A list of insurance companies’ policies can be found here.
I think I had symptoms of Covid-19, but I wasn’t tested. How do I know if I had it?
Scientists are working on developing a test to look for certain antibodies, which are proteins that the body’s immune system produces in response to a foreign pathogen. These antibody tests could tell scientists how many people have been exposed to the new coronavirus and how widespread it is, but they are currently in development and not widely available yet.