The rapid spread of COVID-19 has launched a flurry of new tests for the highly contagious virus, as researchers and medical providers race to track and understand the pandemic.
Yet Illinois — like most of the country — lagged in testing for much of March and April, though more testing has been ramping up across the state.
Most of the testing done by hospitals and medical providers determines whether a patient has an active COVID-19 infection. Currently, the most reliable way to do that is with PCR testing, which detects trace amounts of the virus in specimens collected from the nose, throat or saliva.
This comes in various forms:
Nasal or throat swab tests
Mid-February: Illinois became the first state to test for coronavirus in this manner. Those kits worked, but over the next several weeks many other states reported an initial round of faulty test kits.
February: When the virus was starting to spread across the country, the U.S. was processing only about a dozen tests a day, according to data from the U.S. Centers for Disease Control and Prevention. Those early testing glitches were called “a failing” by Dr. Anthony Fauci, the nation’s top infectious disease expert.
Early March: President Donald Trump declared that “anybody that wants a test can get a test.” Yet Illinois officials and medical providers reported a severe shortage of test kits and required materials — particularly swabs and chemical reagents — because of supply chain problems.
Mid-March: Initially the Illinois Department of Public Health severely restricted testing to the most at-risk patients and required a doctor’s order, citing a national shortage of test kits and supplies.
Late March: Many patients locally and across the country began reporting lengthy test result delays, with some experiencing wait times as long as two weeks, because of backlogs at labs and a shortage of technicians who process the tests.
March 29: Gov. J.B. Pritzker sets a statewide goal of performing 10,000 tests a day to fight the pandemic. Though testing does increase, it will take weeks to reach that bar.
March 29: Abbott Laboratories in north suburban Lake Bluff announced development of a new rapid COVID-19 test that could produce results in as little as five minutes — the fastest turnaround available.
April 16: Pritzker widened testing to any patients with COVID-19 symptoms, even without a previously required doctor’s order; he also announced a massive expansion of testing in Illinois, saying test kit materials had been secured and supply chain problems resolved.
April 24: Illinois for the first time exceeds Prtizker’s goal of 10,000 daily tests, performing more than 16,000 tests in a 24-hour period.
This approach doesn’t require nasal swabs, which have been short supply during the pandemic.
April 24: A study led by the Yale School of Public Health concluded that saliva samples “provided greater detection sensitivity and consistency” than the nasopharyngeal testing approach, according to a Yale news release. Researchers called for further validation of their findings.
The first in-home test allowed self-collection of a sample from the patient’s nose using a nasal swab and saline solution. The patient then mails the sample in an insulated package for processing, the FDA said in a news release.
These self-collection kits were initially available only to health care workers and first responders, but access was widened in mid-May.
The first at-home saliva test was approved for emergency use in May, where patients send in self-collected spit samples.
April 21: The FDA granted emergency clearance for the first at-home coronavirus test by LabCorp, based in North Carolina, which allows self-collection of a sample with a nasal swab.
May 8: The FDA issued an emergency use authorization for the first at-home COVID-19 test using self-collected saliva samples.
Although scientists and medical experts say these tests are critical to learning who has the virus, none of these approaches is foolproof. For example, if enough of the virus isn’t present in the saliva or nasal/throat sample, the result can be a false negative.
The CDC also cautions that testing negative for COVID-19 doesn’t mean the person won’t get sick. “It is possible that you were very early in your infection when your specimen was collected and that you could test positive later,” according to the CDC website. “Or you could be exposed later and then develop illness.”
In the case of nasal and throat samples, the nation for weeks has grappled with a dearth of test kits, swabs, chemical reagents and other supplies required to perform and process these tests. Many of these tests need to be processed by labs; some have reported a shortage of lab technicians, leading to a bottleneck of tests and lengthy delays for results.
There’s also antibody testing, sometimes called serology testing. Instead of detecting the actual virus, this test looks for blood proteins called antibodies that are produced while the body fights an infection. A positive result means the patient was infected at some point with SARS-CoV-2, the virus that causes COVID-19.
Researchers say antibody testing of large populations can give crucial information about the virus, like how prevalent the virus really is, how many people contract COVID-19 without experiencing symptoms and whether survivors have immunity.
April 2: The FDA gives emergency-use approval to the first antibody test. Several others have since been approved.
April 24: Though some local medical providers have been offering antibody testing, Pritzker said the state won’t be pushing for it yet because of concerns over accuracy. “We’re craving answers in an uncertain time and antibody tests offer the potential for more security,” he said at a news briefing. “But I’m afraid we’ve seen many of these tests promoted in a way that errs on the side of irresponsible.”
April 29: Congressional leaders including U.S. Rep. Raja Krishnamoorthi of northwest suburban Schaumburg, launched an investigation into the accuracy of many of the antibody tests that were on the market under an FDA policy that did not require review by the agency.
May 3: Swiss drugmaker Roche said the FDA granted emergency approval for its antibody test, which it claims is 100% accurate in detecting antibodies and 99.8% accurate in determining the absence of antibodies; the company said the test draws blood intravenously, which is more accurate than other ways of drawing blood. Several other companies have also received FDA approval for their antibody tests.
May 4: The FDA announced stricter rules for antibody tests; manufacturers must now show data indicating their tests are accurate and apply for emergency use authorization within 10 days of going on the market.
Drawbacks of antibody testing
Some physicians and lawmakers have expressed concerns about the accuracy of certain types of antibody tests, and the nation’s top physicians are working to validate serology tests.
Because it can take days to two weeks after infection with COVID-19 for a patient to develop antibodies; the test might not detect antibodies even in an infected patient, according to the CDC.
“Antibody tests should not be used as the only way to diagnose someone as being currently sick with COVID-19,” the CDC says on its website.
The Associated Press contributed.
Diagram sources: CDC, Cleveland Clinic, Northwestern, BioMedomics, Spectrum Solutions, Chicago Tribune reporting
