Orange County erroneously inflated its COVID-19 testing numbers for more than a month — logging 30,000 more tests than it should have — before the error was discovered and fixed, officials acknowledged this week.
This error may stoke further skepticism in the numbers.
“That’s quite concerning,” said Eva O’Keefe of San Clemente, founder of Stay Healthy OC/COVID-19, a Facebook group with nearly 500 members that tries to deal in data, not rumors. She has been asking the county to explain puzzling changes in reports on testing, hospitalizations, ICU beds and more — and hasn’t been getting clear answers.
“We need a lot more transparency,” she said.
First, it’s important to understand the differences between the two most common COVID-19 tests.
- The only test that counties are supposed to report is the diagnostic test, which finds active infections. It’s called the polymerase chain reaction, or PCR, test, and uses a cotton swab to penetrate high into the nose and throat to collect gunk. That material is then examined for the virus’ genetic markers. PCR tests can identify the sick, but can’t detect if someone once had COVID-19 and then recovered.
- The serology, or blood antibody, test offers that window to the past. A positive result means the body mounted an immune response to the virus in recent weeks or months — but serology tests are notoriously unreliable for determining who’s sick right now. That’s why it’s not supposed to be used, or counted, in officially reported testing numbers.
But for five weeks — from April 28 through June 3 — Orange County mistakenly added about 30,000 serology test results to its “cumulative tests to date” figures, according to Orange County Public Health Services.
That made it appear testing was greater in O.C. than it actually was, to the tune of some 13 percent by the time the extra tests were removed.
Positive serology tests were not counted as positive COVID-19 cases, the county said.
The mistake may have made the pandemic appear less intense in Orange County than it really was to people who were following the numbers closely.
One way to measure whether a region’s cases are going up just because of more testing, or because there’s actually more disease spreading, is by looking at what percentage of tests are coming back positive. Including more tests could make the slice of positive tests seem smaller, and the outbreak less acute.
“As you comingle the PCR with the antibody tests, that’s going to make the denominator a lot larger, so your positivity rate is going to decrease,” O’Keefe said.
It wasn’t clear if the serology tests translated into lower “positivity” scores for Orange County in the calculations used by the state to monitor progress. Officials did not immediately provide a detailed breakdown on the number of PCR vs. serology tests logged over that five-week period. The Southern California News Group filed a public records request for that data, but the county said it had no responsive records.
How’d it happen?
The county explained it this way in an emailed statement:
Orange County downloads lab testing results from the California Reportable Disease Information Exchange (CalREDIE).
There, some lab results are manually processed — showing up in a “staging area,” where local health departments must then process and import them into the CalREDIE database. “This process is typically used for reports that health departments need to see immediately in order to take action; COVID PCR results are processed through this option,” the county said.
Some results, however, are “auto-processed,” which means the lab results don’t show up in the staging area but are automatically processed into the database. Serology tests are auto-processed into the system because there’s no immediate action the health department needs to take on them, the county said.
On April 28, CalREDIE enabled auto-processing of serology tests, and “these serology test results were included with PCR test results in ‘Cumulative Tests To Date,’ ” the county said.
“Serology tests never should’ve been included as they are not an appropriate diagnostic test. This was an error, which is why they were removed when HCA leadership became aware of the issue. Approximately 30,000 serology tests were removed.”
However, even though officials realized the mistake June 3 and stopped including additional serology tests in the numbers starting June 4, they didn’t remove the ones they’d already reported until June 26 when they launched a new COVID-19 data dashboard. It does not report any information about serology tests.
When pressed for more details on precisely how serology tests came to be added to PCR tests — who’s charged with reviewing the numbers before they’re posted? how did the error continue for so long without detection? — the county said that, once CalREDIE enabled auto-processing of serology tests, “total COVID tests” would technically include serology tests because they are, indeed, COVID tests.
“However, the intent of the public reporting is actually total PCR COVID tests, which is why including serology tests was incorrect,” the statement said. “When the OC Health Care Agency’s leadership became aware of this, we responded accordingly and as quickly as we could given the current workload and demands on our team.”
It remains unclear precisely how the error came to the county’s attention.
O’Keefe gave the county’s new COVID-19 dashboard mixed reviews.
“Aesthetically, it looks a lot better,” she said. “I like the ZIP codes and the deaths per ZIP. But some charting is missing. I think people want to see those charts and trends. I know some local doctors have been doing a lot of the charting that’s missing from the county — it’s been up to the citizens to take this on.”
The county of Santa Clara is doing a better job, she said, going so far as to reporting exact co-morbidities for people who’ve died, to help dispel rumors and hoaxes. “The more information people have, the better they can decide for themselves whether they want to take a risk or not,” she said. “We’re not getting that type of transparency from the county.”
The county said that the information is being posted in “near-real time,” so the data aren’t perfect and there will be changes. The website states that information is always subject to clarification and will be updated as needed, it said.
“Meantime, we are proud to serve OC residents with the best information from our State and Federal partners, that helps everyone make the best decisions to mitigate the spread of COVID-19 and save lives,” the county said.