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Mendocino County Health Officer Update Regarding False Positives and New Cases

Post Date:06/01/2020 7:47 PM

On May 28, 2020, the California Department of Public Health (CDPH) notified Mendocino County Public Health of a positive COVID-19 case in the North Coast region. This individual was asymptomatic and tested positive using an Abbott ID Now machine at a healthcare facility outside of the County. In the same week a second asymptomatic individual in the Ukiah Valley region with a known COVID-19 exposure was tested with a different Abbott machine in a hospital with a positive result. Abbott machines should not be use for screening asymptomatic individuals for COVID-19. Following the two positives on two different Abbott machines, the North Coast individual was re-tested at Mendocino Coast District Hospital (MCDH) and the Ukiah Valley individual was re-tested at a local hospital. Both hospitals used a different testing system to authenticate the Abbott results and both tests came back negative. Mendocino County consulted with CDPH regarding the false positives from the Abbott machines. Based on FDA information CDPH recommends the Abbott machines only be used for individuals who are showing symptoms and are suspected of having COVID-19.

Following the guidance from CDPH and in collaboration with Adventist Health and Mendocino Coast District Hospital, the Abbott machine results for these two asymptomatic individuals are being deemed false positives, therefore both cases are being removed from Mendocino County’s case count. The Ukiah Valley individual is in quarantine for fourteen-days due to their known exposure to a COVID-19 case per the Health Officer’s blanket quarantine order. Quarantine is not required for the North Coast individual who had no known contact to a COVID-19 case.

“We are very appreciative of the work of Dr. Doohan and Mendocino County Public Health in helping us sort all of this out,” said Dr. William Miller, Chief of Staff at MCDH.  “We know this is a time of great anxiety for many people. It is helpful to know what the true status of COVID is in our communities. We must remember that all tests must be interpreted in the greater context of prevalence and accurate interpretation is critical.  This will be tremendously important as we take steps to thoughtfully roll back some of the shelter-in-place requirements that have allowed us to stay ahead of this pandemic here in California,” he adds.

While we have removed the two false positives from the Mendocino County COVID-19 Statistics, Mendocino County was notified of two additional cases today.  With these changes the current case count remains at 30 cases (17 recovered, 1 hospitalized, and 12 home isolation). 

The two new cases were individuals tested through Optum Serv and sent to a Quest commercial lab for processing. These two people were contacted by the Optum Serv/Quest and advised to isolate at home and that Public Health would contact them soon.  The lab failed to notify Public Health of these new cases, resulting in a delay in case contact tracing. Upon notification of the situation, Public Health immediately reached out to the reporting parties, the lab and Optum Serv, to address the matter.  The responses were quick from reporting parties and contact tracing is in process on the two new cases. Bekkie Emery, Department Operations Center (DOC) Manager reported, “Optum Serv has been very responsive and is working with the Mendocino County Public Health team to resolve the situation as well as identify where the reporting breakdown occurred to prevent future occurrences.”       

For more on COVID-19:

Call Center: (707) 234-6052 or email

The call center is open Monday-Friday from 8:00 a.m. – 5:00 p.m.