Michigan's capacity to test for COVID-19 doubled to about 300 individual tests Thursday, with the delivery of additional diagnostic supplies from the federal Centers for Disease Control and Prevention.

The supplies are being validated, or tested for reliability, at the Michigan Department of Health and Human Services Bureau of Laboratories in Lansing, and will be ready for use by the end of the week, state health officials said.

The supplies arrived as the number of states with confirmed COVID-19 infections grew to 18 on Thursday. Eleven people have died, including 10 in Washington State and one in California.

Michigan previously only had enough supplies to test about 140 individuals, raising concern from public health officials that the state wouldn't be prepared for an outbreak here.

“We want Michiganders to know that their state laboratory is ready and able to provide testing for COVID-19,” said Dr. Joneigh Khaldun, chief medical executive and chief deputy for health at the state health department, in a press release Thursday. “We are currently able to provide same-day turnaround for test results.”

Michigan had no confirmed coronavirus infections through Thursday evening. By Wednesday, eight people in Michigan had been tested for COVID-19, with negative results. Eight more people were tested on Thursday, and the results were pending Thursday night.

Health officials since Jan. 31 have asked a total of 406 people to self-quarantine for 14 days due to travel to areas with high risk of exposure to the coronavirus.

Eighty-two people were in isolation, under active monitoring by county health departments as of Thursday night, an increase of 19 people since Wednesday. The remainder were released after completing their 14 days of quarantine without showing symptoms.

The CDC over the weekend expanded the testing criteria after cases emerged in people who had not traveled to mainland China or been exposed to a person known to be infected.

The expanded criteria will allow Michigan and other states to confirm COVID-19 cases much quicker and slow the spread of this disease in the United States, Khaldun said in a statement.

She added that the state laboratory has been surveying hospital labs across the state to determine their interest in testing for coronavirus,

The federal Food and Drug Administration issued new guidance Feb. 28 to allow private companies, hospitals and universities to develop and process COVID-19 tests.

Previously all tests for coronavirus were being processed at CDC headquarters in Atlanta.

kbouffard@detroitnews.com

Twitter: @kbouffardDN