After at least nine pregnant women were erroneously told they tested negative for the Zika virus and months of flawed testing, the Washington, D.C. Public Health Laboratory Division is being audited by the Centers for Medicare and Medicaid Services, which oversee human tests in labs across the country.
Between July and December of last year, the PHL routinely made mistakes in testing that were noted or corrected for over six months.
The PHL’s procedures failed at two stages. A chemical indicator was over-diluted, rendering it less sensitive to detecting the Zika virus. Furthermore, a lab worker incorrectly entered a formula used to analyze test results into an electronic spreadsheet.
According to D.C. Department of Forensic Sciences Director Jenifer Smith, the city no longer employs any of the staff members who made the mistakes. During the period time of faulty testing, the PHL was understaffed and without permanent management.
One of the nine pregnant women tested positive for the virus. The other eight may have tested positive for antibodies that could signal the presence of the virus, but the tests were inconclusive. According to Centers for Disease Control and Prevention protocol, these cases ought to have been treated as positive for Zika.
Zika is a virus that can be contracted after a bite from a carrier mosquito or through unprotected sexual activity with an infected partner. Those infected often exhibit symptoms of fever, red eyes, rash, joint pain and headaches.
If a woman is pregnant when she contracts the virus, her baby may suffer from the birth defect microcephaly, a condition characterized by a shrunken head and an underdeveloped brain.
As of March 8, the CDC has recorded 5,109 cases of Zika in the United States, and 38,099 cases in United States territories. Of the cases in the U.S., a majority came from people who travelled abroad to other affected areas. Currently, there are no medicines or vaccines to treat or prevent Zika.
Samples from approximately 400 District residents will be retested for the virus in light of the mistakes, including 294 from pregnant women that were sent directly to the CDC.
The audit could potentially lead to the Centers for Medicare and Medicaid Services to revoke the PHL’s license, shuttering it until it comes into compliance and preventing the facility from serving District residents.
The health care providers of individuals who tested positive for the virus during the retest process have been notified. The children of the infected pregnant women will be tested again after one year to assess their vitals and development.
The botched Zika testing was a major topic at the annual meeting of the D.C City Council’s Committee on the Judiciary and Public Safety on Feb. 28. Smith explained the reaction to the inaccurate testing.
“Our response reflects our ethic and desire to be transparent,” Smith said. “As we received the initial results, we contacted over 3,000 medical providers, set up conference calls and a contact email to ensure their questions would be answered. We went one step further, and working with the mayor’s staff, we held a press conference sharing this information with the public.”
CDC spokesperson Benjamin Haynes said the center will be working to address the failed tests in the coming months.
“CDC has confirmed in the last two weeks that of the 62 samples they have retested to date, that two of the tests were incorrect,” Haynes wrote in an email to The Hoya. “The additional testing on the remaining samples will occur over the next few weeks and confirmed if any others are shown to be positive.”
PHL Director Anthony Tran, who discovered the testing mistakes last year, is no longer taking interviews.
According to Smith, the lab is now working on changing its protocols in an attempt to prevent future errors.
“Since the discovery of these errors, several measures have been instituted into the PHL to ensure that newly added tests are preforming optimally,” Smith said at the committee meeting. “PHL will conduct more extensive internal validation testing on all CDC issued protocols beyond what is recommended to verify that the tests work. Additionally, all protocols that involve a person embedding a calculation into a worksheet will be technically reviewed by at least one other individual for verification.”
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