False-negative tests may cloud picture of coronavirus spread in Ga.
As Georgia ramps up diagnostic testing for active coronavirus cases, some patients and public health experts fear a weakness in the state’s disease surveillance network isn’t just obtaining enough test kits and supplies but potential false negative results.
It’s unclear how common false negative tests are in the U.S., though some preliminary research in China found inaccurate results as high as 30%, according to one survey. Doctors and public health experts say the culprits are a difficult process used to obtain most patient samples and the rapid deployment of test kits that haven’t been fully vetted by federal regulators.
Testing is still the nation’s first line of defense against the disease, and experts say collection efforts and testing are improving. And widespread testing is needed to help ensure COVID-19 can be contained.
But as the state starts to reopen, false negative tests could create false senses of security and inadvertently spread the virus.
If just a few people at a company, for instance, receive a false negative report and return to work, “you’ve just brought people back who are infected and don’t know it,” said Drew Maloney, chairman of Capstone Healthcare, a molecular and genetics diagnostic lab in Sandy Springs.
A Mayo Clinic report said even if tests are 90% accurate, “the magnitude of risk from false-negative test results will be substantial as testing becomes more widespread and the prevalence of COVID-19 infection rises.”
The novel coronavirus was discovered only late last year, and companies rushed to produce tests. The U.S. Food and Drug Administration has issued emergency clearances known as emergency use authorizations (EUAs) for more than four dozen thus far. But these EUAs do not have the full rigor of complete clinical trials, though companies say their tests are highly accurate.
Sonali Garg was tested for Covid-19 at the Georgia Tech, CVS site and received a negative result but still has symptoms Thursday, April 23, 2020. Her energy level is low and she is feeling aches and pains at her Brookhaven home where she is still trying to work. Sick individuals at the testing site were told to swab their own noses, which is not the CDC recommendation. JENNI GIRTMAN / FOR THE AJCPhoto: The Atlanta Journal-Constitution
Earlier this month, the FDA approved an EUA for the first at-home collection kit.
Though the FDA and Atlanta-based Centers for Disease Control and Prevention have given the green light for tests using samples taken from within nostrils, most kits use a nasopharyngeal sample that involves sending a long swab deep into the nasal cavity. Other tests use a deep swab of the throat similar to a strep test.
Dr. Robert Jansen, chief medical officer at Grady Memorial Hospital, said in an interview this month false negatives happen.
“But I think most of that is really a sampling problem as opposed to the actual test,” he said. “It’s a difficult sample to get. You have to do it the right way and it’s uncomfortable for the patient.
“If you get a negative test, but the clinical picture is consistent with the infection, you treat them like that’s what they have,” Jansen said.
A team of researchers at Georgia Tech and Piedmont Healthcare developed a digital tool to help doctors decide whether to re-test patients who displayed COVID-19 symptoms but tested negative for the virus.
“One of our big worries in using a brand-new test like the coronavirus test is that it will miss real cases, and this tool helps prevent that,” Dr. Bronwen Garner, an infectious disease expert at Piedmont, said in a Georgia Tech newsletter announcing the tool. “It also helps reassure physicians when they get a negative result that it is probably a true negative.”
Georgia is now reporting about 6,000 tests processed per day, a marked improvement over just a few weeks ago. On Sunday, the state ranked 35th nationally in testing per capita.
‘I did the best I could’
After days of feeling sick with a headache, fever, cough and other symptoms, Sonali Garg secured an appointment one afternoon last week at the CVS Health drive-through testing site at Georgia Tech.
After waiting in line for more than an hour, Garg was feeling horrible. What she witnessed at the front of the line, where tests were administered, only made her feel worse. She realized drivers were having to administer the nasal swab tests on themselves, which she said seemed crazy.
Sonali Garg was tested for Covid-19 at the Georgia Tech, CVS site and received a negative result but still has symptoms Thursday, April 23, 2020. Her energy level is low and she is feeling aches and pains at her Brookhaven home where she is still trying to work. Sick individuals at the testing site were told to swab their own noses, which is not the CDC recommendation. JENNI GIRTMAN / FOR THE AJCPhoto: The Atlanta Journal-Constitution
When it was her turn, she rolled her window down an inch, as instructed, and a testing technician handed her a swab and explained the test. After sticking the swab in each nostril, she handed it back to the technician.
“It’s very difficult,” she said. “It’s uncomfortable. It’s scary. I’m not used to sticking things up my nose. I did the best I could.”
About 20 minutes later she received the result: negative. But Garg, an attorney, had no confidence in the finding. When she explained the process to doctors in her family, including several who are treating coronavirus patients, they told her a self-administered test like that was unreliable.
“Every physician I’ve told is just flabbergasted,” she said.
Garg remains convinced that there’s a good chance she has the virus and she’s self-quarantining at her Brookhaven townhome.
CVS Health uses a new rapid testing platform by Abbott Laboratories called ID Now that can produce results within minutes. The pharmacy company announced this week it will roll out the testing devices at 1,000 locations nationwide in the coming weeks.
“The self-administered swab we are using with the Abbott test is allowed by the CDC and is an option that can help protect health care workers and conserve scarce (personal protective equipment),” CVS spokeswoman Christine Cramer said.
John Koval, a spokesman for Abbott, said the ID Now meets “all testing criteria in the FDA’s Emergency Use Authorization guidance.”
“The test’s clinical evaluation data is consistent with other COVID-19 molecular tests to have received FDA EUA,” he said.
‘I didn’t do it right’
Jayne-Anne Ahmann and her boyfriend Hunter Tredway also had doubts about their negatives tests at the CVS site.
Ahmann started exhibiting symptoms earlier this month. She got a priority test because she’s considered a first responder as a community behavioral specialist for children in group homes.
“I knew I didn’t do it right as soon as I did it,” she said. “I didn’t know what I was doing. They couldn’t really communicate with me through the window and their PPE.”
Tredway, who drove Ahmann to the appointment hadn’t pre-registered, but they gave him a test, too.
Tredway said he did not get as sick as Ahmann, whose condition worsened in the coming days. Ahmann said she called her doctor’s office at Emory and she said a nurse was incredulous that she and others swabbed themselves.
Ahmann eventually got a second test at Emory when her condition didn’t improve. The clinician used a nasopharyngeal swab, which Ahmann described as “something I would not have been able to do on my own.”
Ahmann said her doctor called 24 hours later to say the second test also came back negative.
“But she diagnosed me as positive any way,” Ahmann said, “because she said the false negative rates are so high.”