A looming shortage in lab materials is threatening to delay coronavirus test results and cause officials to undercount the number of Americans with the virus.

The slow pace of coronavirus testing has created a major gap in the U.S. public health response. The latest problem involves an inability to prepare samples for testing, creating uncertainties in how long it will take to get results.


CDC Director Robert Redfield told POLITICO on Tuesday that he is not confident that U.S. labs have an adequate stock of the supplies used to extract genetic material from any virus in a patient’s sample — a critical step in coronavirus testing.

“The availability of those reagents is obviously being looked at,” he said, referring to the chemicals used for preparing samples. “I’m confident of the actual test that we have, but as people begin to operationalize the test, they realize there’s other things they need to do the test.”

The coronavirus task force convened by the White House is also aware of the shortages, and one official said members are working on it.

The growing scarcity of these “RNA extraction” kits is the latest trouble for U.S. labs, which have struggled to implement widespread coronavirus testing in the seven weeks since the country diagnosed its first case. Epidemiologists and public health officials say that the delayed rollout, caused in part by a botched CDC test, has masked the scope of the U.S. outbreak and hobbled efforts to limit it.


If enough processing kits aren’t available, the risk that testing will be disrupted is “huge,” said Michael Mina, associate medical director of molecular diagnostics at Brigham and Women's Hospital in Boston.

“RNA extraction is the first step in being able to perform” a coronavirus test, he said. “If we cannot perform this step, the [coronavirus] test cannot be performed.”

Qiagen, a major supplier of the kits, confirmed that its product is backordered due to “the extraordinary pace” at which the world has increased coronavirus testing over the last few weeks.

Public health labs across the U.S. have tested more than 5,000 people, according to the Trump administration. HHS Secretary Alex Azar told lawmakers on Tuesday that U.S. labs’ capacity could grow to 10,000-20,000 people per day by the end of the week.


“Increased demand for testing has the potential to exhaust supplies needed to perform the test itself,” said Robin Patel, president of the American Society for Microbiology. That would limit the testing capacity of public health, hospital and commercial labs alike, she added.

Complicating the situation, most labs have been running at least two tests per patient — although that could soon change. The CDC issued interim guidelines on Monday that minimize the number of tests required for a diagnosis. The agency says labs can combine a patient’s nose and throat samples into one test, a move experts say will cut in half the amount of supplies used to test each person.

But Redfield said he doesn’t know how the agency would deal with any scarcity of RNA extraction kits and reagents that arise. “I don’t know the answer to that question,” he said when asked how the CDC would handle such a situation — adding that he is hopeful “there will be mechanisms between multiple manufacturers to correct” it.

Mandy Cohen, North Carolina’s secretary of health, said that a shortage of extraction kits and other chemicals had hampered testing in her state. “Folks were saying, ‘We are sending you the [test] kits,’ and I don’t think they understood at first what exact part of the supply chain we needed,” she said. “We needed extraction kits.”

An FDA spokesperson said that the agency is contacting labs that are testing for the coronavirus “to understand their supply issues and assist where we can.”

The FDA has also approved a change to the CDC diagnostic test that allows labs to switch from Qiagen’s RNA extraction method to another manufactured by Roche, says Denny Russell, who leads the coronavirus response at Washington state’s public health lab. But getting his lab ready to use the Roche method could take a week in part because technicians will need training to use it.

Commercial labs, which have recently started running coronavirus tests, have not experienced any supply shortages, according to a spokesperson for the American Clinical Laboratory Association.

In the meantime, Qiagen has told customers that it may not be able to fill large standing orders, because it is trying to provide smaller numbers of kits to as many labs as possible, said spokesperson Robert Reitze. The company is ramping up production of RNA extraction kits at manufacturing sites in Hilden, Germany; Barcelona, Spain; and Germantown, Md.


Nancy Cook and Dan Goldberg contributed to this report.