Virginia Gov. Ralph Northam (D) said Wednesday that he had directed the state Health Department to figure out how to capture more racial and ethnic information about patients who test positive for covid-19.

“We are seeing racial disparities in covid cases in places like New Orleans and New York,” Northam said, “and we must be able to measure this here in Virginia.”

Currently, Virginia has such data only for the cases handled directly by state health officials, which is 47 percent of reported positive cases, said Norman Oliver, the state health commissioner. The private labs and health-care providers that have handled the other 53 percent of cases are not collecting the data, he said. The state faces the same problem with deaths attributed to the coronavirus, Oliver said.

State health workers who investigate each case attempt to get the data, he said, but if it is not collected by the initial health-care provider, it might not be recoverable.

Going forward, though, Northam has instructed the Health Department to push providers to record demographics.

“We know long-standing racial inequities … lead to differences in underlying health conditions” that can make African Americans particularly vulnerable to the coronavirus, Northam said.

Of the 47 percent of cases for which the state does have such data, 28 percent of those infected are black or African American, Oliver said. The state’s population is about 20 percent black. The disparity does not appear to be as evident among fatalities in which race was recorded, at just under 19 percent black or African American.

Oliver said he is sending a letter to physicians and other health workers urging them to record the data. He added that the unified command system coordinating Virginia’s response to the outbreak has a special group assigned to monitor the issue of racial disparity, noting that people of color are more likely to live in crowded, urban settings where transmission of the disease is harder to avoid.

The rest of the Washington region faces a similar challenge in understanding the racial component of the disease’s spread.

The District does not know the races of about 42 percent of the 1,444 people who are confirmed to have tested positive, because that information is not disclosed by laboratories, leaving city officials to ask patients directly during interviews.

In a Wednesday call between the D.C. Council and the mayor’s office, council member Kenyan R. McDuffie (D-Ward 5) asked whether the city could provide the race of people tested for coronavirus in addition to those who tested positive and died.

City Administrator Rashad M. Young (D) said the city was working to automate a system to collect demographic information. Young said it is not feasible to call the more than 8,000 people who have already been tested.