PHOENIX — A presumptive positive case of COVID-19 at Arizona's state lab has now been deemed negative after cross-contamination, state health officials say.
A 90-year-old man tested presumptive positive last Wednesday at Arizona's state lab.
According to the CDC, "a presumptive positive case has tested positive by a public health laboratory and is pending confirmatory testing at CDC."
AZ STATE LAB: I just confirmed that the 90-year-old's test at Arizona's state lab was false. During the extraction process some of a positive specimen contaminated another area on a test plate. /1 @abc15 #ABC15 #COVID2019 #COVID2019 #CoronavirusOutbreak— Nicole Grigg (@NicoleSGrigg) March 17, 2020
A representative with AZDHS tells ABC15 that a specimen falsely tested positive at the state lab because during the extraction process some of a positive specimen contaminated another area on the test plate.
"Changes were made inside the lab to ensure this doesn't happen again," an AZDHS official said.
ABC15 was told that a false positive can happen from time to time.
"Our lab is very experienced," they went on to say.
Arizona's state lab no longer sends tests to the CDC for confirmation because the state lab is now verified.
The verification process happens after the state lab has so many of the same results with the CDC.
As of Tuesday, the state lab has tested 221 people. That number tested is just 21 people more from 24 hours before, far below the average daily tests at other states.
AZDHS has strict criteria for testing people in Arizona. Officials say they are depending on commercial labs, and they expect testing numbers to increase this week as private labs are up and running.