Hospitals across the St. Louis area were working to open drive-thru sites to collect samples from those who may be infected. As of Thursday, there were at least seven collection sites operating in the metro area. At least six more were set to open within the next week, according to interviews with health departments and local hospital systems.

State officials say 14 mobile sites are operating statewide.

Still, national shortages of testing supplies like swabs and reagents used in the analysis of samples have lead to strict rules on who can get tested.

In Missouri and Illinois, for example, state health departments say people qualify if they have respiratory symptoms severe enough to be hospitalized and they have tested negative for other possible causes, such as flu. People also may get tested if they have a fever or respiratory symptoms and have had direct contact with someone with a confirmed case of COVID-19, or have traveled to an area with a known large outbreak in the U.S. or abroad, including the Seattle area.

The rules on testing may obscure the true scope of the COVID-19 pandemic and leave sick people like Eva Heward, 54, of St. Peters, in the dark.