Health officials in Washington D.C. had to redo public health laboratory tests for Zika in 300 women, including two who were told that they had tested negative, when in fact their results showed positive for the mosquito-borne disease.
A spokesperson for the Centers of Disease Control and Prevention said that a routine check of lab practices showed that all of the D.C.’s Zika tests were coming back negative, raising alarms about how accurate they really were, Reuters reports.
CDC officials working in the lab since January found out that technicians handling Zika tests were missing a step, which has caused all of the results to show as negative, according to Dr. Wendi Kuhnert-Tallman, co-lead on the CDC team checking the lab.
The inaccurate tests were completed from July 14 to December 14 of 2016, the CDC says.
A total of 409 specimens had to be sent for re-testing, which included 294 samples from pregnant women. CDC is checking the latter samples, while the rest were sent to other CDC-approved public health labs.
Of the 62 test results that have been returned to the D.C. office, 60 were negative and 2 were positive. The positive results were re-confirmed to show that the women had been recently infected with a flavivirus, which includes Zikka, dengue and Chikungunya.
What that means is that we did see evidence of past infection, but we can’t say for sure it’s Zika.
She added that the CDC has completed around 100more tests, which are being sent back to the labs and doctors who ordered them. There are 129 more pending. “We anticipate those will be finalized within two to three weeks.”
The District of Columbia Department of Forensic Sciences Public Health Laboratory has stopped Zika testing and is under suspension for it until it can show the CDC that it is performing the tests correctly, Kuhnert-Tallman said.