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The total number of COVID-19 tests conducted in Orange County was mistakenly inflated for more than a month beginning in late April in data released to the public, an error that may have painted a rosier picture of the pandemic than the reality in the region.
For roughly five weeks, county staff incorrectly added 30,000 serology tests to its “cumulative tests to date” figure, which made it appear that more testing for the virus was happening than was the case.
The cumulative testing figure reported by the county is supposed to be a count of how many diagnostic tests — which detect whether someone was infected with the virus at the moment of testing — were conducted countywide, Dr. Clayton Chau, director of the Orange County Health Care Agency and the county’s interim health officer, said during a media briefing Thursday.
Serology tests, which officials say are not meant to be included in the cumulative testing figure, determine whether the body has mounted an immune response to the virus in recent weeks or months. Those tests are not reliable in determining whether someone is sick at the moment of testing, experts say.