This illustration, created at the Centers for Disease Control and Prevention (CDC), reveals ultrastructural morphology exhibited by coronaviruses. A novel coronavirus, named Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2), was identified as the cause of an outbreak of respiratory illness first detected in Wuhan, China in 2019. The illness caused by this virus has been named coronavirus disease 2019 (COVID-19). (CDC/Alissa Eckert, MS)

Montgomery County is closing all testing sites Friday until further notice after issues were raised by the state with some testing kits.

Anyone who was tested at a county-sponsored clinic in the past two weeks should be retested at another community-based clinic, the county said on its website.

Maryland's department of health raised questions about protocols used with some test kits by AdvaGenix, which uses self-administered kits to collect saliva. These kits account for about 7% of all tests conducted in the county, adding up to hundreds every day.