The Missouri Department of Health And Senior Services removed antibody tests from its count of COVID-19 tests on Saturday, revealing that the state has been less aggressive on viral testing than had previous appeared.
On Friday, the total number of tests reported was 172,946, but after changes were made on Saturday, the count dropped to 148,303, a decline of 14%.
Dr. Randall Williams, director of the state health department, addressed changes made to the state data in a statement released on Saturday.
“As we continue to learn more about this virus and new tests emerge, we will continue providing better data with greater clarity and transparency to help Missourians make the best decisions for their health care possible,” Williams wrote.
Many states, including Virginia, Texas and Georgia, acknowledged last week that they had combined viral (PCR) and antibody (serological) tests in their reporting and said they were taking steps to separate the results.
However, at a press conference on Thursday, Williams had denied that Missouri was combining test numbers in public reporting after other states were discovered to be following this practice.
“About four states have gotten in a lot of trouble because they tried to conflate their numbers – I think to drive up their numbers, and we don’t do that here in Missouri,” Williams told reporters.
The state health departments had been following guidance from the federal Centers for Disease Control and Prevention, which had advised states to combine both COVID-19 viral tests with tests for antibodies.
However, the combining of these tests provides a misleading picture of virus trends, according to infectious disease specialists, because viral (or PRC) tests show when someone currently has illness, while antibody (or serological) tests show if someone has been exposed and potentially developed some immunity.
Experts have also questioned the accuracy of many of the antibody tests that have been available.
Test numbers reported on Friday showed that 2.8% percent of Missouri’s roughly 6,150,000 residents had been tested, but after the antibody tests were removed, the data show that 2.4% of the population has been tested.
The state dashboards showed on Saturday that 17,108 tests were listed as antibody, rather than viral tests. However, it was not immediately clear why the new number of viral tests declined by more than 24,000.
The state health department did not respond to inquiries from KCUR last week regarding the reporting practices.
In Missouri Gov. Mike Parson’s regular COVID-19 briefings, he frequently touts the state’s aggressive approach to testing and the increasing capacity to test, which experts say is vital to understanding the spread of the virus.
However, the new charts show the rate of viral testing has been essentially unchanged since late April. Most of the increases in testing that had appeared in state data during the past few weeks has been due to increases in antibody tests.
Kansas health department spokeswoman Kristi Zears wrote in an email to KCUR last week that test numbers were not combined unless a local health department identified a positive antibody test as a probable case.
