The Connecticut Department of Public Health (DPH) announced Monday the discovery of dozens of false positive coronavirus tests, attributing the error to a “flaw” in a test system.
At least 90 tests, which were performed through Thermo Fisher Scientific, have yielded false positives, according to the DPH.
As the Hartford Courant reported:
In the one-month period from June 15 to July 17, the department said 144 people tested positive after their samples were processed through a system manufactured by Thermo Fisher Scientific of Waltham, Massachusetts.
Acting DPH Commissioner Dr. Deidre Gifford said most of the “evidence affected” came from nursing homes and emphasized that the error applies to a “minority of evidence in the state.” Those who have received a positive test, he said, should “absolutely assume that such a positive result is correct until such time as their provider informs them of any changes”:
The Thermo Fisher system bug was discovered when the director of the public health laboratory, Dr. Jafar Razeq, and his team were working to validate group testing, which is the process of testing a large number of samples at once. To validate that process, the team had to use samples that were already known to be positive.
But the validation process also required the team to determine the strength or weakness of the positive samples, and that information is not readily available in the Thermo Fisher system. So Razeq and his team went into the raw data to extract the information they needed and found that some of the test results were not really positive.
Dr. Razeq called the discovery “alarming”.
“When we started looking at the background information on these samples, we realized that these samples should not have been reported as positive,” he said.
After retesting 161 positive samples associated with 144 patients, the team found that only 54 patients tested positive for the virus.
“If it hadn’t been for us looking in the pool tests to use some of these previously known positive samples, there was no indication that any of these reported positive results would have been questioned,” said Razeq.
Connecticut has reported 48,055 positive cases of the Chinese coronavirus and 4,406 related deaths. The state’s current travel notice requires people to “a state that has a new daily positive test rate greater than 10 per 100,000 residents or a state with a positivity rate of 10% or more on a 7-day moving average ”at quarantine for 14 days.
