THE HEAD OF THE MASSACHUSETTS COVID-19 command center said she has dramatically stepped up testing at the state’s nursing homes and wants to test all residents and employees as quickly as possible.

“We know how vulnerable they are so I want to test all nursing homes in Massachusetts,” said Marylou Sudders, the governor’s secretary of health and human services.

Sudders said a National Guard mobile testing unit in the last few days has doubled its amount of testing at nursing homes, going from 700 to 900 tests a day to 1,700 to 1,800 tests a day.

She said tests have been conducted so far at more than 200, or 52 percent, of the state’s 386 nursing home facilities. Initially, only residents and employees with symptoms were tested, but now Sudders said standard operating procedure calls for testing everyone at every facility to get a baseline read on the disease. She noted that nursing homes cannot be compelled to allow residents and staff to be tested. (State officials earlier said there were 383 nursing homes in the state with 38,000 residents.)

The baseline testing initiative is a significant development in the effort to bring the spread of COVID-19 under control at nursing homes, which have been ravaged by the disease. On Friday, the state’s COVID-19 dashboard indicated the number of new cases at long-term care facilities increased by 749, or 9 percent. The number of new deaths increased by 113, bringing the total to 1,429, which is 56 percent of all COVID-19 deaths in the state.

Asked specifically about testing at Holyoke and Chelsea Soldiers’ Homes, Sudders said all residents and staff at those facilities have been tested but she said they have not been retested. Retesting, often called surveillance testing, is done to see if the disease has resurfaced in some way.