Blanco County was made aware Monday of eight individuals in the southern part of the county who had serology (antibody) testing performed over the weekend as a result of exposure to a confirmed case outside the county. All eight tests came back positive.

According to Blanco County Emergency Management, it is important to understand the difference between PCR testing and serology testing. PCR testing looks for the virus itself in the nose, throat or other areas in the respiratory tract to determine if there is an active infection, and is the type of test which is utilized to diagnose COVID-19. On the other hand, serology testing looks for antibodies. Antibodies are formed by the body to fight off infections. One of these types of antibodies start to become detectable within the first week of becoming infected and will remain present for months. A second type of these antibodies start to become detectable about two weeks after the person becomes infected, and will also remain present for months or even years.

As such, these antibodies do not necessarily mean that someone has an active infection, it could be a previous infection that has already resolved. Results from antibody testing should not be used as the sole basis to diagnose or exclude COVID-19 infection or to inform infection status. Further testing (PCR) is necessary.

Because none of these eight individuals have any symptoms of COVID-19 and antibody testing alone cannot be used to diagnose COVID-19, the state does not consider these to be confirmed cases at this time, and will not be reflected in the current case count. PCR testing is pending, and the Texas Department of State Health Services is completing a public health investigation. These individuals are considered possible cases and are self-isolating at home.