Testing flaw leads to false positives for coronavirus


By Paul Hughes, Republican-American

HARTFORD — A testing flaw discovered at the State Public Health Laboratory in Rocky Hill led to 90 false positive tests for coronavirus disease processed there in the last month, the Department of Public Health reported Monday.

Acting Public Health Commissioner Diedre S. Gifford said immediate steps were taken to notify the misdiagnosed patients involved and their health care providers of the incorrect test results that were reported between mid-June and mid-July.

“The good news for us is we caught it,” Gov. Ned Lamont said.

The Public Health Lab uncovered a flaw July 15 in one of the testing systems it uses to detect the novel coronavirus that led to 90 out of 144 people tested from June 15 to July 17 receiving a false positive test report.

Manufacturer Thermo Fisher Scientific and the federal Food and Drug Administration were notified of the finding.

Public health officials are also investigating how many more testing laboratories may have used the Thermo Fisher Scientific test.

MANY OF THE PERSONS with false positive test results are nursing home residents, one of the most vulnerable populations to COVID-19.

Gifford said any nursing home resident with a false positive test result will be retested as soon as possible.

Yet, the inaccurate test results could have led to some incorrectly diagnosed patients being exposed to the virus because they were isolated with other COVID positive cases in nursing homes after the false positive test.

Public health officials were unable to provide figures Monday on how many nursing home residents may have been exposed to COVID-19 in this way, and how many may have died as a result. Nursing home residents have accounted for more than 60% of the approximately 4,400 confirmed and probable COVID-19 deaths.

Gifford said DPH officials are working with nursing home operators to ascertain how many residents may have been exposed or died after having received a flawed test result.

“Many of these individuals had multiple tests. So, the one test result would not have necessarily changed their clinical management,” she said.

THE NUMBER OF FALSE POSITIVE TESTS could be higher than the 90 that the Department of Public Health reported because it is not known how many other testing labs in Connecticut used the same diagnostic test.

“We don’t know the answer to that question,” said Jafar H. Razeq, director of the Public Health Lab.

DPH officials are inquiring if other testing labs in Connecticut used the Thermo Fisher Scientific testing system, and if they discovered any false positive results, too. This information will be provided to the public, said Josh Geballe, chief operating officer of the Lamont administration.

Gifford stressed that anybody who received a positive test for COVID-19 should assume that result is correct unless a medical provider informs them otherwise.

“This is going to apply to a minority of tests in this state. We are working to find out exactly what percentage would be potentially implicated by this system,” she said.

Gifford and Geballe said the Public Health Lab processed approximately 2,200 of the 273,540 diagnostic tests that were reported between June 15 and July 17. Gifford declined to estimate how many false test results may have resulted from the flawed Thermo Fisher Scientific test beyond what the DPH reported.

“I don’t want to jump to any conclusions about numbers because that would not be appropriate, but we are talking to partner labs in this state of Connecticut. We want to understand the potential here,” she said.

Gifford said DPH officials also want to find out if any other testing labs also discovered the same flaw in the Thermo Fisher Scientific tests and contacted patients and health care providers, as well.

Yale epidemiologist Albert Ko agreed with Gifford that the discovery of the testing flaw should not undermine people’s confidence in the ability of tests to detect the virus.

“No test is perfect,” Ko said.

AN ADDITIONAL 27,323 DIAGNOSTIC TESTS were received since Friday, and 162 new cases of COVID-19 were reported to DPH, according to the latest state statistics Monday.

Lamont said the percentage of positive results over that three-day worked out to 0.6%, which he described as one of the lowest positive rates in the country. To date, there have been 655,309 tests received. This figure includes multiple tests of the same patient or specimen.

There were 10 more fatalities reported since Friday. This brought the death toll to 4,408.

There was also a net decrease of 12 hospitalized patients between new hospital admissions and discharges to 54 statewide.

THE NAUGATUCK VALLEY HEALTH DISTRICT reported that of the false positive tests announced Monday, four were for people within its jurisdiction of Ansonia, Beacon Falls, Derby, Naugatuck, Seymour and Shelton. The health district said it was also notified of another false positive from a different laboratory for a previously reported case.

The health district did not state what towns the people lived in who falsely tested positive, but adjusted its data to account for the false positive tests. The health district reported Monday there have been 416 confirmed cases in Naugatuck, which is four less than the number reported Thursday. There have been 57 confirmed cases in Beacon Falls as of Monday, which is the same number the health district reported Thursday.

There have been 37 confirmed deaths associated with coronavirus and three probable deaths in Naugatuck, according to the health district, and none in Beacon Falls.

The Chesprocott Health District, which serves Cheshire, Prospect and Wolcott, said Tuesday the 90 false positive reports did not include any in its jurisdiction. As of Friday, the Chesprocott reported there have been 74 cases in Prospect and no coronavirus-related deaths in town.

Elio Gugliotti contributed to this report.